beta4 changes (#26 )

These changes are mostly in underlying libraries; however, this now uses the [inspired by F#](https://git.bitbadger.solutions/bit-badger/inspired-by-fsharp) library to handle the feed parsing pipeline and optional return values Reviewed-on: #26
Fix user delete process (#25 )
2024-08-06 23:20:17 +00:00 · 2024-06-15 12:55:45 -04:00 · 2024-06-12 07:49:56 -04:00
35 changed files with 867 additions and 535 deletions
--- a/src/app-config.php
+++ b/src/app-config.php
@ -1,10 +1,20 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * Feed Reader Central Common Application Configuration
+ *
+ * This script sets up the environment required for the application and loads the user configuration
+ *
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 use BitBadger\PDODocument\{AutoId, Configuration};
 use FeedReaderCentral\Data;

 /** The current Feed Reader Central version */
-const FRC_VERSION = '1.0.0-beta1';
+const FRC_VERSION = '1.0.0-beta4';

 /**
 * Drop .0 or .0.0 from the end of the version to format it for display
@ -13,7 +23,7 @@ const FRC_VERSION = '1.0.0-beta1';
 */
 function display_version(): string {
    [$major, $minor, $rev] = explode('.', FRC_VERSION);
-    $minor = $minor == '0' ? '' : ".$minor";
+    $minor = $minor === '0' ? '' : ".$minor";
    $rev = match (true) {
        $rev == '0'                 => '',
        str_starts_with($rev, '0-') => substr($rev, 1),
@ -25,7 +35,7 @@ function display_version(): string {
 require __DIR__ . '/vendor/autoload.php';
 require 'user-config.php';

-Configuration::$pdoDSN = 'sqlite:' . implode(DIRECTORY_SEPARATOR, [__DIR__, 'data', DATABASE_NAME]);
+Configuration::useDSN('sqlite:' . implode(DIRECTORY_SEPARATOR, [__DIR__, 'data', DATABASE_NAME]));
 Configuration::$autoId = AutoId::Number;
 Data::ensureDb();

--- a/src/cli-start.php
+++ b/src/cli-start.php
@ -1,4 +1,14 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * Command Line Utility Start Script
+ *
+ * This loads the environment needed for a command line utility
+ *
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 require 'app-config.php';

--- a/src/composer.json
+++ b/src/composer.json
@ -1,6 +1,6 @@
 {
  "name": "bit-badger/feed-reader-central",
-  "minimum-stability": "dev",
+  "minimum-stability": "beta",
  "require": {
    "php": ">=8.2",
    "bit-badger/pdo-document": "^1",
--- a/src/composer.lock
+++ b/src/composer.lock
@ -4,23 +4,70 @@
        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
        "This file is @generated automatically"
    ],
-    "content-hash": "4f0add59e384feb6787acf3685c9e031",
+    "content-hash": "2966efd32e555ad8b63351673e75b5a5",
    "packages": [
+        {
+            "name": "bit-badger/inspired-by-fsharp",
+            "version": "v1.0.0-beta2",
+            "source": {
+                "type": "git",
+                "url": "https://git.bitbadger.solutions/bit-badger/inspired-by-fsharp",
+                "reference": "fad428a4e40b606987499b17bb2d5b7d4b04502d"
+            },
+            "require": {
+                "php": "^8.2"
+            },
+            "require-dev": {
+                "phpoption/phpoption": "^1",
+                "phpunit/phpunit": "^11"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "BitBadger\\InspiredByFSharp\\": "./src"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Daniel J. Summers",
+                    "email": "daniel@bitbadger.solutions",
+                    "homepage": "https://bitbadger.solutions",
+                    "role": "Developer"
+                }
+            ],
+            "description": "PHP utility classes whose functionality is inspired by their F# counterparts",
+            "keywords": [
+                "option",
+                "result"
+            ],
+            "support": {
+                "email": "daniel@bitbadger.solutions",
+                "rss": "https://git.bitbadger.solutions/bit-badger/inspired-by-fsharp.rss",
+                "source": "https://git.bitbadger.solutions/bit-badger/inspired-by-fsharp"
+            },
+            "time": "2024-07-29T17:58:33+00:00"
+        },
        {
            "name": "bit-badger/pdo-document",
-            "version": "v1.0.0-alpha2",
+            "version": "v1.0.0-beta9",
            "source": {
                "type": "git",
                "url": "https://git.bitbadger.solutions/bit-badger/pdo-document",
-                "reference": "330e27218756df8b93081a17dead8aaec789b071"
+                "reference": "9e0e663811d9dbbdb94a2c04ce8b874e91a7c85b"
            },
            "require": {
+                "bit-badger/inspired-by-fsharp": "^1",
                "ext-pdo": "*",
                "netresearch/jsonmapper": "^4",
                "php": ">=8.2"
            },
            "require-dev": {
-                "phpunit/phpunit": "^11"
+                "phpunit/phpunit": "^11",
+                "square/pjson": "^0.5.0"
            },
            "type": "library",
            "autoload": {
@ -42,19 +89,21 @@
                    "role": "Developer"
                }
            ],
-            "description": "Treat SQLite (and soon PostgreSQL) as a document store",
+            "description": "Treat SQLite and PostgreSQL as document stores",
            "keywords": [
                "database",
                "document",
                "pdo",
+                "postgresql",
                "sqlite"
            ],
            "support": {
+                "docs": "https://bitbadger.solutions/open-source/pdo-document/",
                "email": "daniel@bitbadger.solutions",
                "rss": "https://git.bitbadger.solutions/bit-badger/pdo-document.rss",
                "source": "https://git.bitbadger.solutions/bit-badger/pdo-document"
            },
-            "time": "2024-06-11T11:07:56+00:00"
+            "time": "2024-07-29T20:57:51+00:00"
        },
        {
            "name": "netresearch/jsonmapper",
@ -110,7 +159,7 @@
    ],
    "packages-dev": [],
    "aliases": [],
-    "minimum-stability": "dev",
+    "minimum-stability": "beta",
    "stability-flags": [],
    "prefer-stable": false,
    "prefer-lowest": false,
--- a/src/lib/Data.php
+++ b/src/lib/Data.php
@ -1,4 +1,10 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 namespace FeedReaderCentral;

@ -13,6 +19,9 @@ use Exception;
 */
 class Data
 {
+    /** Prevent instances of this class */
+    private function __construct() {}
+
    /**
     * Create the search index and synchronization triggers for the item table
     *
@ -56,17 +65,17 @@ class Data
    public static function ensureDb(): void
    {
        $tables = Custom::array("SELECT name FROM sqlite_master WHERE type = 'table'", [], new StringMapper('name'));
-        if (!in_array(Table::USER, $tables)) {
-            Definition::ensureTable(Table::USER);
-            Definition::ensureFieldIndex(Table::USER, 'email', ['email']);
+        if (!in_array(Table::User, $tables)) {
+            Definition::ensureTable(Table::User);
+            Definition::ensureFieldIndex(Table::User, 'email', ['email']);
        }
-        if (!in_array(Table::FEED, $tables)) {
-            Definition::ensureTable(Table::FEED);
-            Definition::ensureFieldIndex(Table::FEED, 'user', ['user_id']);
+        if (!in_array(Table::Feed, $tables)) {
+            Definition::ensureTable(Table::Feed);
+            Definition::ensureFieldIndex(Table::Feed, 'user', ['user_id']);
        }
-        if (!in_array(Table::ITEM, $tables)) {
-            Definition::ensureTable(Table::ITEM);
-            Definition::ensureFieldIndex(Table::ITEM, 'feed', ['feed_id', 'item_link']);
+        if (!in_array(Table::Item, $tables)) {
+            Definition::ensureTable(Table::Item);
+            Definition::ensureFieldIndex(Table::Item, 'feed', ['feed_id', 'item_link']);
            self::createSearchIndex();
        }
        $journalMode = Custom::scalar("PRAGMA journal_mode", [], new StringMapper('journal_mode'));
@ -122,7 +131,7 @@ class Data
     */
    public static function userIdField(string $qualifier = ''): Field
    {
-        $userField = Field::EQ('user_id', $_SESSION[Key::USER_ID], ':user');
+        $userField = Field::EQ('user_id', $_SESSION[Key::UserId], ':user');
        $userField->qualifier = $qualifier;
        return $userField;
    }
--- a/src/lib/Feed.php
+++ b/src/lib/Feed.php
@ -1,7 +1,14 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 namespace FeedReaderCentral;

+use BitBadger\InspiredByFSharp\{Option, Result};
 use BitBadger\PDODocument\{
    Configuration, Custom, Document, DocumentException, DocumentList, Exists, Field, Find, Parameters, Patch, Query
 };
@ -15,15 +22,39 @@ class Feed
    // ***** CONSTANTS *****

    /** @var int Do not purge items */
-    public const PURGE_NONE = 0;
+    public const PurgeNone = 0;

    /** @var int Purge all read items (will not purge unread items) */
-    public const PURGE_READ = 1;
+    public const PurgeRead = 1;

    /** @var int Purge items older than the specified number of days */
-    public const PURGE_BY_DAYS = 2;
+    public const PurgeByDays = 2;

    /** @var int Purge items in number greater than the specified number of items to keep */
+    public const PurgeByCount = 3;
+
+    /**
+     * @var int Do not purge items
+     * @deprecated Use Feed::PurgeNone instead
+     */
+    public const PURGE_NONE = 0;
+
+    /**
+     * @var int Purge all read items (will not purge unread items)
+     * @deprecated Use Feed::PurgeRead instead
+     */
+    public const PURGE_READ = 1;
+
+    /**
+     * @var int Purge items older than the specified number of days
+     * @deprecated Use Feed::PurgeByDays instead
+     */
+    public const PURGE_BY_DAYS = 2;
+
+    /**
+     * @var int Purge items in number greater than the specified number of items to keep
+     * @deprecated Use Feed::PurgeByCount instead
+     */
    public const PURGE_BY_COUNT = 3;

    /**
@ -46,12 +77,12 @@ class Feed
     * Create a document from the parsed feed
     *
     * @param ParsedFeed $parsed The parsed feed
-     * @return static The document constructed from the parsed feed
+     * @return Feed The document constructed from the parsed feed
     */
-    public static function fromParsed(ParsedFeed $parsed): static
+    public static function fromParsed(ParsedFeed $parsed): self
    {
-        return new static(
-            user_id:    $_SESSION[Key::USER_ID],
+        return new self(
+            user_id:    $_SESSION[Key::UserId],
            url:        $parsed->url,
            title:      $parsed->title,
            updated_on: $parsed->updatedOn,
@ -64,72 +95,77 @@ class Feed
     * @param int $feedId The ID of the feed to which these items belong
     * @param ParsedFeed $parsed The extracted Atom or RSS feed items
     * @param DateTimeInterface $lastChecked When this feed was last checked (only new items will be added)
-     * @return array ['ok' => true] if successful, ['error' => message] if not
+     * @return Result<true, string> True if successful, an error message if not
     */
-    public static function updateItems(int $feedId, ParsedFeed $parsed, DateTimeInterface $lastChecked): array
+    public static function updateItems(int $feedId, ParsedFeed $parsed, DateTimeInterface $lastChecked): Result
    {
        $results =
            array_map(function ($item) use ($feedId) {
                try {
-                    $existing = Find::firstByFields(Table::ITEM,
+                    $tryExisting = Find::firstByFields(Table::Item,
                        [Field::EQ('feed_id', $feedId), Field::EQ('item_guid', $item->guid)], Item::class);
-                    if ($existing) {
-                        if ($existing->published_on != $item->publishedOn
-                            || ($existing->updated_on != ($item->updatedOn ?? ''))) {
+                    if ($tryExisting->isSome()) {
+                        $existing = $tryExisting->get();
+                        if ($existing->published_on !== $item->publishedOn
+                            || ($existing->updated_on !== ($item->updatedOn ?? ''))) {
                            Item::update($existing->id, $item);
                        }
                    } else {
                        Item::add($feedId, $item);
                    }
-                    return ['ok' => true];
+                    return Result::OK(true);
                } catch (DocumentException $ex) {
-                    return ['error' => "$ex"];
+                    return Result::Error("$ex");
                }
            }, array_filter($parsed->items,
-                fn($it) => date_create_immutable($it->updatedOn ?? $it->publishedOn) >= $lastChecked));
-        $errors = array_map(fn($it) => $it['error'], array_filter($results, fn($it) => array_key_exists('error', $it)));
-        return sizeof($errors) > 0 ? ['error' => implode("\n", $errors)] : ['ok' => true];
+                fn(ParsedItem $it) => date_create_immutable($it->updatedOn ?? $it->publishedOn) >= $lastChecked));
+        $errors = array_map(fn(Result $it) => $it->getError(), array_filter($results, fn($it) => $it->isError()));
+        return sizeof($errors) > 0 ? Result::Error(implode("\n", $errors)) : Result::OK(true);
    }

    /**
     * Purge items for a feed
     *
     * @param int $feedId The ID of the feed to be purged
-     * @return array|string[]|true[] ['ok' => true] if purging was successful, ['error' => message] if not
+     * @return Result<true, string> True if purging was successful, an error message if not
+     * @throws DocumentException If any is encountered
     */
-    private static function purgeItems(int $feedId): array
+    private static function purgeItems(int $feedId): Result
    {
-        if (!array_search(PURGE_TYPE, [self::PURGE_READ, self::PURGE_BY_DAYS, self::PURGE_BY_COUNT])) {
-            return ['error' => 'Unrecognized purge type ' . PURGE_TYPE];
-        }
-
        $fields = [Field::EQ('feed_id', $feedId, ':feed'), Data::bookmarkField(false)];
-        $sql    = Query\Delete::byFields(Table::ITEM, $fields);
-        if (PURGE_TYPE == self::PURGE_READ) {
-            $readField = Field::EQ('is_read', 1, ':read');
-            $fields[]  = $readField;
-            $sql      .= ' AND ' . Query::whereByFields([$readField]);
-        } elseif (PURGE_TYPE == self::PURGE_BY_DAYS) {
-            $fields[] = Field::EQ('', Data::formatDate('-' . PURGE_NUMBER . ' day'), ':oldest');
-            $sql     .= " AND date(coalesce(data->>'updated_on', data->>'published_on')) < date(:oldest)";
-        } elseif (PURGE_TYPE == self::PURGE_BY_COUNT) {
-            $fields[] = Field::EQ('', PURGE_NUMBER, ':keep');
-            $id       = Configuration::$idField;
-            $table    = Table::ITEM;
-            $sql     .= ' ' . <<<SQL
-                AND data->>'$id' IN (
-                    SELECT data->>'$id' FROM $table
-                     WHERE data->>'feed_id' = :feed
-                     ORDER BY date(coalesce(data->>'updated_on', data->>'published_on')) DESC
-                     LIMIT -1 OFFSET :keep
-                )
-                SQL;
+        $sql    = Query\Delete::byFields(Table::Item, $fields);
+
+        switch (PURGE_TYPE) {
+            case self::PurgeRead:
+                $readField = Field::EQ('is_read', 1, ':read');
+                $fields[]  = $readField;
+                $sql      .= ' AND ' . Query::whereByFields([$readField]);
+                break;
+            case self::PurgeByDays:
+                $fields[] = Field::EQ('', Data::formatDate('-' . PURGE_NUMBER . ' day'), ':oldest');
+                $sql     .= " AND date(coalesce(data->>'updated_on', data->>'published_on')) < date(:oldest)";
+                break;
+            case self::PurgeByCount:
+                $fields[] = Field::EQ('', PURGE_NUMBER, ':keep');
+                $id       = Configuration::$idField;
+                $table    = Table::Item;
+                $sql     .= ' ' . <<<SQL
+                    AND data->>'$id' IN (
+                        SELECT data->>'$id' FROM $table
+                         WHERE data->>'feed_id' = :feed
+                         ORDER BY date(coalesce(data->>'updated_on', data->>'published_on')) DESC
+                         LIMIT -1 OFFSET :keep
+                    )
+                    SQL;
+                break;
+            default:
+                return Result::Error('Unrecognized purge type ' . PURGE_TYPE);
        }
        try {
            Custom::nonQuery($sql, Parameters::addFields($fields, []));
-            return ['ok' => true];
+            return Result::OK(true);
        } catch (DocumentException $ex) {
-            return ['error' => "$ex"];
+            return Result::Error("$ex");
        }
    }

@ -138,67 +174,62 @@ class Feed
     *
     * @param int $feedId The ID of the feed to be refreshed
     * @param string $url The URL of the feed to be refreshed
-     * @return array|string[]|true[] ['ok' => true] if successful, ['error' => message] if not
+     * @return Result<true, string> True if successful, an error message if not
     */
-    public static function refreshFeed(int $feedId, string $url): array
+    public static function refreshFeed(int $feedId, string $url): Result
    {
-        $feedRetrieval = ParsedFeed::retrieve($url);
-        if (key_exists('error', $feedRetrieval)) return $feedRetrieval;
-        $feed = $feedRetrieval['ok'];
+        return ParsedFeed::retrieve($url)
+            ->bind(function (ParsedFeed $feed) use ($feedId, $url) {
+                try {
+                    $feedDoc = Find::byId(Table::Feed, $feedId, self::class);
+                    if ($feedDoc->isNone()) return Result::Error('Could not derive date last checked for feed');
+                    $lastChecked = date_create_immutable($feedDoc->get()->checked_on ?? WWW_EPOCH);

-        try {
-            $feedDoc = Find::byId(Table::FEED, $feedId, self::class);
-            if (!$feedDoc) return ['error' => 'Could not derive date last checked for feed'];
-            $lastChecked = date_create_immutable($feedDoc->checked_on ?? WWW_EPOCH);
-
-            $itemUpdate = self::updateItems($feedId, $feed, $lastChecked);
-            if (key_exists('error', $itemUpdate)) return $itemUpdate;
-
-            $patch = [
-                'title'      => $feed->title,
-                'updated_on' => $feed->updatedOn,
-                'checked_on' => Data::formatDate('now')
-            ];
-            if ($url == $feed->url) $patch['url'] = $feed->url;
-            Patch::byId(Table::FEED, $feedId, $patch);
-        } catch (DocumentException $ex) {
-            return ['error' => "$ex"];
-        }
-
-        return PURGE_TYPE == self::PURGE_NONE ? ['ok' => true] : self::purgeItems($feedId);
+                    return self::updateItems($feedId, $feed, $lastChecked)
+                        ->bind(function () use ($feed, $feedId, $url) {
+                            $patch = [
+                                'title'      => $feed->title,
+                                'updated_on' => $feed->updatedOn,
+                                'checked_on' => Data::formatDate('now')
+                            ];
+                            if ($url !== $feed->url) $patch['url'] = $feed->url;
+                            Patch::byId(Table::Feed, $feedId, $patch);
+                            return Result::OK(true);
+                        })
+                        ->bind(fn() => PURGE_TYPE === self::PurgeNone ? Result::OK(true) : self::purgeItems($feedId));
+                } catch (DocumentException $ex) {
+                    return Result::Error("$ex");
+                }
+            });
    }

    /**
     * Add an RSS feed
     *
     * @param string $url The URL of the RSS feed to add
-     * @return array ['ok' => feedId] if successful, ['error' => message] if not
+     * @return Result<int, string> The feed ID if successful, an error message if not
     */
-    public static function add(string $url): array
+    public static function add(string $url): Result
    {
-        $feedExtract = ParsedFeed::retrieve($url);
-        if (key_exists('error', $feedExtract)) return $feedExtract;
+        return ParsedFeed::retrieve($url)
+            ->bind(function (ParsedFeed $feed) {
+                try {
+                    $fields = [Field::EQ('user_id', $_SESSION[Key::UserId]), Field::EQ('url', $feed->url)];
+                    if (Exists::byFields(Table::Feed, $fields)) {
+                        return Result::Error("Already subscribed to feed $feed->url");
+                    }

-        $feed = $feedExtract['ok'];
+                    Document::insert(Table::Feed, self::fromParsed($feed));

-        try {
-            $fields = [Field::EQ('user_id', $_SESSION[Key::USER_ID]), Field::EQ('url', $feed->url)];
-            if (Exists::byFields(Table::FEED, $fields)) {
-                return ['error' => "Already subscribed to feed $feed->url"];
-            }
+                    $doc = Find::firstByFields(Table::Feed, $fields, self::class);
+                    if ($doc->isNone()) return Result::Error('Could not retrieve inserted feed');

-            Document::insert(Table::FEED, self::fromParsed($feed));
-
-            $doc = Find::firstByFields(Table::FEED, $fields, static::class);
-            if (!$doc) return ['error' => 'Could not retrieve inserted feed'];
-
-            $result = self::updateItems($doc->id, $feed, date_create_immutable(WWW_EPOCH));
-            if (key_exists('error', $result)) return $result;
-
-            return ['ok' => $doc->id];
-        } catch (DocumentException $ex) {
-            return ['error' => "$ex"];
-        }
+                    return self::updateItems($doc->get()->id, $feed, date_create_immutable(WWW_EPOCH))
+                        ->bind(fn() => Result::OK($doc->get()->id));
+                } catch (DocumentException $ex) {
+                    return Result::Error("$ex");
+                }
+            });
    }

    /**
@ -206,18 +237,17 @@ class Feed
     *
     * @param Feed $existing The existing feed
     * @param string $url The URL with which the existing feed should be modified
-     * @return bool[]|string[] [ 'ok' => true ] if successful, [ 'error' => message ] if not
+     * @return Result<true, string> True if successful, an error message if not
     */
-    public static function update(Feed $existing, string $url): array
+    public static function update(Feed $existing, string $url): Result
    {
        try {
-            Patch::byFields(Table::FEED,
-                [Field::EQ(Configuration::$idField, $existing->id), Field::EQ('user_id', $_SESSION[Key::USER_ID])],
+            Patch::byFields(Table::Feed,
+                [Field::EQ(Configuration::$idField, $existing->id), Field::EQ('user_id', $_SESSION[Key::UserId])],
                ['url' => $url]);
-
            return self::refreshFeed($existing->id, $url);
        } catch (DocumentException $ex) {
-            return ['error' => "$ex"];
+            return Result::Error("$ex");
        }
    }

@ -230,44 +260,42 @@ class Feed
     */
    public static function retrieveAll(int $user = 0): DocumentList
    {
-        return $user == 0
-            ? Find::all(Table::FEED, self::class)
-            : Find::byFields(Table::FEED, [Field::EQ('user_id', $user)], self::class);
+        return $user === 0
+            ? Find::all(Table::Feed, self::class)
+            : Find::byFields(Table::Feed, [Field::EQ('user_id', $user)], self::class);
    }

    /**
     * Refresh all feeds
     *
-     * @return array|true[]|string[] ['ok' => true] if successful,
-     *      ['error' => message] if not (may have multiple error lines)
+     * @return Result<true, string> True if successful an error message if not (may have multiple error lines)
     */
-    public static function refreshAll(): array
+    public static function refreshAll(): Result
    {
-        try {
-            $feeds = self::retrieveAll($_SESSION[Key::USER_ID]);
+        $errors = [];

-            $errors = [];
-            foreach ($feeds->items() as $feed) {
-                $result = self::refreshFeed($feed->id, $feed->url);
-                if (key_exists('error', $result)) $errors[] = $result['error'];
-            }
+        try {
+            self::retrieveAll($_SESSION[Key::UserId])->iter(function (Feed $feed) use (&$errors) {
+                self::refreshFeed($feed->id, $feed->url)
+                    ->mapError(function (string $err) use (&$errors) { $errors[] = $err; });
+            });
        } catch (DocumentException $ex) {
-            return ['error' => "$ex"];
+            return Result::Error("$ex");
        }

-        return sizeof($errors) == 0 ? ['ok' => true] : ['error' => implode("\n", $errors)];
+        return empty($errors) ? Result::OK(true) : Result::Error(implode("\n", $errors));
    }

    /**
     * Retrieve a feed by its ID for the current user
     *
     * @param int $feedId The ID of the feed to retrieve
-     * @return static|false The data for the feed if found, false if not found
+     * @return Option<Feed> A `Some` value with the data for the feed if found, `None` otherwise
     * @throws DocumentException If any is encountered
     */
-    public static function retrieveById(int $feedId): static|false
+    public static function retrieveById(int $feedId): Option
    {
-        $doc = Find::byId(Table::FEED, $feedId, static::class);
-        return $doc && $doc->user_id == $_SESSION[Key::USER_ID] ? $doc : false;
+        return Find::byId(Table::Feed, $feedId, static::class)
+            ->filter(fn($it) => $it->user_id === $_SESSION[Key::UserId]);
    }
 }
--- a/src/lib/Item.php
+++ b/src/lib/Item.php
@ -1,4 +1,10 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 namespace FeedReaderCentral;

@ -57,7 +63,7 @@ class Item
     */
    public static function add(int $feedId, ParsedItem $parsed): void
    {
-        Document::insert(Table::ITEM, new static(
+        Document::insert(Table::Item, new self(
            feed_id:      $feedId,
            title:        $parsed->title,
            item_guid:    $parsed->guid,
@ -76,7 +82,7 @@ class Item
     */
    public static function update(int $id, ParsedItem $parsed): void
    {
-        Patch::byId(Table::ITEM, $id, [
+        Patch::byId(Table::Item, $id, [
            'title'        => $parsed->title,
            'published_on' => $parsed->publishedOn,
            'updated_on'   => $parsed->updatedOn,
--- a/src/lib/ItemList.php
+++ b/src/lib/ItemList.php
@ -1,7 +1,14 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 namespace FeedReaderCentral;

+use BitBadger\InspiredByFSharp\Option;
 use BitBadger\PDODocument\{Configuration, Custom, DocumentException, DocumentList, Field, Parameters, Query};
 use BitBadger\PDODocument\Mapper\DocumentMapper;

@ -15,18 +22,8 @@ class ItemList
    /** @var DocumentList<ItemWithFeed> The items matching the criteria, lazily iterable */
    private DocumentList $dbList;

-    /** @var string The error message generated by executing a query */
-    public string $error = '';
-
-    /**
-     * Is there an error condition associated with this list?
-     *
-     * @return bool True if there is an error condition associated with this list, false if not
-     */
-    public function isError(): bool
-    {
-        return $this->error != '';
-    }
+    /** @var Option<string> The error message generated by executing a query */
+    private Option $error;

    /** @var bool Whether to render a link to the feed to which the item belongs */
    public bool $linkFeed = false;
@ -42,32 +39,33 @@ class ItemList
     *
     * @param string $itemType The type of item being displayed (unread, bookmark, etc.)
     * @param string $returnURL The URL to which the item page should return once the item has been viewed
-     * @param array|Field[] $fields The fields to use to restrict the results
+     * @param Field[] $fields The fields to use to restrict the results
     * @param string $searchWhere Additional WHERE clause to use for searching
     */
    private function __construct(public string $itemType, public string $returnURL = '', array $fields = [],
                                 string $searchWhere = '')
    {
-        $allFields = [Data::userIdField(Table::FEED), ...$fields];
+        $this->error = Option::None();
+        $allFields   = [Data::userIdField(Table::Feed), ...$fields];
        try {
            $this->dbList = Custom::list(
                ItemWithFeed::SELECT_WITH_FEED . ' WHERE '
-                    . Query::whereByFields(array_filter($allFields, fn($it) => $it->paramName <> ':search'))
+                    . Query::whereByFields(array_filter($allFields, fn($it) => $it->paramName !== ':search'))
                . "$searchWhere ORDER BY coalesce(item.data->>'updated_on', item.data->>'published_on') DESC",
                Parameters::addFields($allFields, []), new DocumentMapper(ItemWithFeed::class));
        } catch (DocumentException $ex) {
-            $this->error = "$ex";
+            $this->error = Option::Some("$ex");
        }
    }

    /**
     * Create an item list with all the current user's bookmarked items
     *
-     * @return static An item list with all bookmarked items
+     * @return ItemList An item list with all bookmarked items
     */
-    public static function allBookmarked(): static
+    public static function allBookmarked(): self
    {
-        $list = new static('Bookmarked', '/?bookmarked', [Data::bookmarkField(qualifier: Table::ITEM)]);
+        $list = new self('Bookmarked', '/?bookmarked', [Data::bookmarkField(qualifier: Table::Item)]);
        $list->linkFeed = true;
        return $list;
    }
@ -75,11 +73,11 @@ class ItemList
    /**
     * Create an item list with all the current user's unread items
     *
-     * @return static An item list with all unread items
+     * @return ItemList An item list with all unread items
     */
-    public static function allUnread(): static
+    public static function allUnread(): self
    {
-        $list = new static('Unread', fields: [Data::unreadField(Table::ITEM)]);
+        $list = new self('Unread', fields: [Data::unreadField(Table::Item)]);
        $list->linkFeed = true;
        return $list;
    }
@ -88,11 +86,11 @@ class ItemList
     * Create an item list with all items for the given feed
     *
     * @param int $feedId The ID of the feed for which items should be retrieved
-     * @return static An item list with all items for the given feed
+     * @return ItemList An item list with all items for the given feed
     */
-    public static function allForFeed(int $feedId): static
+    public static function allForFeed(int $feedId): self
    {
-        $list = new static('', "/feed/items?id=$feedId", [Data::feedField($feedId, Table::FEED)]);
+        $list = new self('', "/feed/items?id=$feedId", [Data::feedField($feedId, Table::Feed)]);
        $list->showIndicators = true;
        return $list;
    }
@ -101,24 +99,24 @@ class ItemList
     * Create an item list with unread items for the given feed
     *
     * @param int $feedId The ID of the feed for which items should be retrieved
-     * @return static An item list with unread items for the given feed
+     * @return ItemList An item list with unread items for the given feed
     */
-    public static function unreadForFeed(int $feedId): static
+    public static function unreadForFeed(int $feedId): self
    {
-        return new static('Unread', "/feed/items?id=$feedId&unread",
-            [Data::feedField($feedId, Table::FEED), Data::unreadField(Table::ITEM)]);
+        return new self('Unread', "/feed/items?id=$feedId&unread",
+            [Data::feedField($feedId, Table::Feed), Data::unreadField(Table::Item)]);
    }

    /**
     * Create an item list with bookmarked items for the given feed
     *
     * @param int $feedId The ID of the feed for which items should be retrieved
-     * @return static An item list with bookmarked items for the given feed
+     * @return ItemList An item list with bookmarked items for the given feed
     */
-    public static function bookmarkedForFeed(int $feedId): static
+    public static function bookmarkedForFeed(int $feedId): self
    {
-        return new static('Bookmarked', "/feed/items?id=$feedId&bookmarked",
-            [Data::feedField($feedId, Table::FEED), Data::bookmarkField(qualifier: Table::ITEM)]);
+        return new self('Bookmarked', "/feed/items?id=$feedId&bookmarked",
+            [Data::feedField($feedId, Table::Feed), Data::bookmarkField(qualifier: Table::Item)]);
    }

    /**
@ -126,15 +124,15 @@ class ItemList
     *
     * @param string $search The item search terms / query
     * @param bool $isBookmarked Whether to restrict the search to bookmarked items
-     * @return static An item list match the given search terms
+     * @return ItemList An item list match the given search terms
     */
-    public static function matchingSearch(string $search, bool $isBookmarked): static
+    public static function matchingSearch(string $search, bool $isBookmarked): self
    {
        $fields = [Field::EQ('content', $search, ':search')];
-        if ($isBookmarked) $fields[] = Data::bookmarkField(qualifier: Table::ITEM);
-        $list = new static('Matching' . ($isBookmarked ? ' Bookmarked' : ''),
+        if ($isBookmarked) $fields[] = Data::bookmarkField(qualifier: Table::Item);
+        $list = new self('Matching' . ($isBookmarked ? ' Bookmarked' : ''),
            "/search?search=$search&items=" . ($isBookmarked ? 'bookmarked' : 'all'), $fields,
-            ' AND ' . Table::ITEM . ".data->>'" . Configuration::$idField . "' IN "
+            ' AND ' . Table::Item . ".data->>'" . Configuration::$idField . "' IN "
                . '(SELECT ROWID FROM item_search WHERE content MATCH :search)');
        $list->showIndicators = true;
        $list->displayFeed    = true;
@ -146,29 +144,29 @@ class ItemList
     */
    public function render(): void
    {
-        if ($this->isError()) {
-            echo "<p>Error retrieving list:<br>$this->error";
+        if ($this->error->isSome()) {
+            echo "<p>Error retrieving list:<br>{$this->error->get()}";
            return;
        }
-        $return = $this->returnURL == '' ? '' : '&from=' . urlencode($this->returnURL);
+        $return = $this->returnURL === '' ? '' : '&from=' . urlencode($this->returnURL);
        echo '<article>';
        if ($this->dbList->hasItems()) {
-            foreach ($this->dbList->items() as $it) {
-                echo '<p>' . hx_get("/item?id=$it->id$return", strip_tags($it->title)) . '<br><small>';
+            $this->dbList->iter(function (ItemWithFeed $item) use ($return) {
+                echo '<p>' . hx_get("/item?id=$item->id$return", strip_tags($item->title)) . '<br><small>';
                if ($this->showIndicators) {
-                    if (!$it->isRead()) echo '<strong>Unread</strong> &nbsp; ';
-                    if ($it->isBookmarked()) echo '<strong>Bookmarked</strong> &nbsp; ';
+                    if (!$item->isRead()) echo '<strong>Unread</strong> &nbsp; ';
+                    if ($item->isBookmarked()) echo '<strong>Bookmarked</strong> &nbsp; ';
                }
-                echo '<em>' . date_time($it->updated_on ?? $it->published_on) . '</em>';
+                echo '<em>' . date_time($item->updated_on ?? $item->published_on) . '</em>';
                if ($this->linkFeed) {
                    echo ' &bull; ' .
-                        hx_get("/feed/items?id={$it->feed->id}&" . strtolower($this->itemType),
-                            htmlentities($it->feed->title));
+                        hx_get("/feed/items?id={$item->feed->id}&" . strtolower($this->itemType),
+                            htmlentities($item->feed->title));
                } elseif ($this->displayFeed) {
-                    echo ' &bull; ' . htmlentities($it->feed->title);
+                    echo ' &bull; ' . htmlentities($item->feed->title);
                }
                echo '</small>';
-            }
+            });
        } else {
            echo '<p><em>There are no ' . strtolower($this->itemType) . ' items</em>';
        }
--- a/src/lib/ItemWithFeed.php
+++ b/src/lib/ItemWithFeed.php
@ -1,7 +1,14 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 namespace FeedReaderCentral;

+use BitBadger\InspiredByFSharp\Option;
 use BitBadger\PDODocument\{Configuration, Custom, DocumentException, Field, Parameters, Query};
 use BitBadger\PDODocument\Mapper\{DocumentMapper, ExistsMapper};

@ -11,12 +18,12 @@ use BitBadger\PDODocument\Mapper\{DocumentMapper, ExistsMapper};
 class ItemWithFeed extends Item
 {
    /** @var string The body of the `FROM` clause to join item and feed */
-    public const FROM_WITH_JOIN = Table::ITEM . ' INNER JOIN ' . Table::FEED
-        . ' ON ' . Table::ITEM . ".data->>'feed_id' = " . Table::FEED . ".data->>'id'";
+    public const FROM_WITH_JOIN = Table::Item . ' INNER JOIN ' . Table::Feed
+        . ' ON ' . Table::Item . ".data->>'feed_id' = " . Table::Feed . ".data->>'id'";

    /** @var string The `SELECT` clause to add the feed as a property to the item's document */
    public const SELECT_WITH_FEED =
-        'SELECT json_set(' . Table::ITEM . ".data, '$.feed', json(" . Table::FEED . '.data)) AS data FROM '
+        'SELECT json_set(' . Table::Item . ".data, '$.feed', json(" . Table::Feed . '.data)) AS data FROM '
        . self::FROM_WITH_JOIN;

    /** @var Feed The feed to which this item belongs */
@ -31,9 +38,9 @@ class ItemWithFeed extends Item
    private static function idAndUserFields(int $id): array
    {
        $idField = Field::EQ(Configuration::$idField, $id, ':id');
-        $idField->qualifier = Table::ITEM;
-        $userField = Field::EQ('user_id', $_SESSION[Key::USER_ID], ':user');
-        $userField->qualifier = Table::FEED;
+        $idField->qualifier = Table::Item;
+        $userField = Field::EQ('user_id', $_SESSION[Key::UserId], ':user');
+        $userField->qualifier = Table::Feed;
        return [$idField, $userField];
    }

@ -55,10 +62,10 @@ class ItemWithFeed extends Item
     * Retrieve an item via its ID
     *
     * @param int $id The ID of the item to be retrieved
-     * @return ItemWithFeed|false The item if it is found, false if not
+     * @return Option<ItemWithFeed> A `Some` value with the item if it is found, `None` otherwise
     * @throws DocumentException If any is encountered
     */
-    public static function retrieveById(int $id): ItemWithFeed|false
+    public static function retrieveById(int $id): Option
    {
        $fields = self::idAndUserFields($id);
        return Custom::single(self::SELECT_WITH_FEED . ' WHERE ' . Query::whereByFields($fields),
--- a/src/lib/Key.php
+++ b/src/lib/Key.php
@ -1,18 +1,27 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 namespace FeedReaderCentral;

 /**
 * Session and other keys used for array indexes
 */
-class Key {
-
+readonly class Key
+{
    /** @var string The $_SESSION key for the current user's e-mail address */
-    public const USER_EMAIL = 'FRC_USER_EMAIL';
+    public const UserEmail = 'FRC_USER_EMAIL';

    /** @var string The $_SESSION key for the current user's ID */
-    public const USER_ID = 'FRC_USER_ID';
+    public const UserId = 'FRC_USER_ID';

    /** @var string The $_REQUEST key for the array of user messages to display */
-    public const USER_MSG = 'FRC_USER_MSG';
+    public const UserMsg = 'FRC_USER_MSG';
+
+    /** Prevent instances of this class */
+    private function __construct() {}
 }
--- a/src/lib/ParsedFeed.php
+++ b/src/lib/ParsedFeed.php
@ -1,25 +1,34 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 namespace FeedReaderCentral;

+use BitBadger\InspiredByFSharp\Result;
 use DOMDocument;
 use DOMElement;
 use DOMException;
 use DOMNode;

-class ParsedFeed
+/**
+ * A feed, as parsed from the Atom or RSS XML
+ */
+readonly class ParsedFeed
 {
-    /** @var string The URL for the feed */
-    public string $url = '';
-
-    /** @var string The title of the feed */
-    public string $title = '';
-
-    /** @var ?string When the feed was last updated */
-    public ?string $updatedOn = null;
-
-    /** @var ParsedItem[] The items contained in the feed */
-    public array $items = [];
+    /**
+     * Constructor
+     *
+     * @param string $url The URL for the feed
+     * @param string $title The title of the feed
+     * @param string|null $updatedOn When the feed was last updated
+     * @param ParsedItem[] $items The items contained in the feed
+     */
+    public function __construct(public string $url = '', public string $title = '', public ?string $updatedOn = null,
+                                public array $items = []) {}

    /** @var string The XML namespace for Atom feeds */
    public const ATOM_NS = 'http://www.w3.org/2005/Atom';
@ -42,8 +51,9 @@ class ParsedFeed
     * @return bool False, to delegate to the next error handler in the chain
     * @throws DOMException If the error is a warning
     */
-    private static function xmlParseError(int $errno, string $errstr): bool {
-        if ($errno == E_WARNING && substr_count($errstr, 'DOMDocument::loadXML()') > 0) {
+    private static function xmlParseError(int $errno, string $errstr): bool
+    {
+        if ($errno === E_WARNING && substr_count($errstr, 'DOMDocument::loadXML()') > 0) {
            throw new DOMException($errstr, $errno);
        }
        return false;
@ -53,16 +63,17 @@ class ParsedFeed
     * Parse a feed into an XML tree
     *
     * @param string $content The feed's RSS content
-     * @return array|DOMDocument[]|string[] ['ok' => feed] if successful, ['error' => message] if not
+     * @return Result<DOMDocument, string> The feed if successful, an error message if not
     */
-    public static function parseFeed(string $content): array {
+    public static function parseFeed(string $content): Result
+    {
        set_error_handler(self::xmlParseError(...));
        try {
            $feed = new DOMDocument();
            $feed->loadXML($content);
-            return ['ok' => $feed];
+            return Result::OK($feed);
        } catch (DOMException $ex) {
-            return ['error' => $ex->getMessage()];
+            return Result::Error($ex->getMessage());
        } finally {
            restore_error_handler();
        }
@ -75,9 +86,10 @@ class ParsedFeed
     * @param string $tagName The name of the tag whose value should be obtained
     * @return string The value of the element (or "[element] not found" if that element does not exist)
     */
-    public static function rssValue(DOMNode $element, string $tagName): string {
+    public static function rssValue(DOMNode $element, string $tagName): string
+    {
        $tags = $element->getElementsByTagName($tagName);
-        return $tags->length == 0 ? "$tagName not found" : $tags->item(0)->textContent;
+        return $tags->length === 0 ? "$tagName not found" : $tags->item(0)->textContent;
    }

    /**
@ -85,13 +97,14 @@ class ParsedFeed
     *
     * @param DOMDocument $xml The XML received from the feed
     * @param string $url The actual URL for the feed
-     * @return array|Feed[]|string[] ['ok' => feed] if successful, ['error' => message] if not
+     * @return Result<ParsedFeed, string> The feed if successful, an error message if not
     */
-    private static function fromRSS(DOMDocument $xml, string $url): array {
+    private static function fromRSS(DOMDocument $xml, string $url): Result
+    {
        $channel = $xml->getElementsByTagName('channel')->item(0);
        if (!($channel instanceof DOMElement)) {
            $type = $channel?->nodeType ?? -1;
-            return ['error' => "Channel element not found ($type)"];
+            return Result::Error("Channel element not found ($type)");
        }

        // The Atom namespace provides a lastBuildDate, which contains the last time an item in the feed was updated; if
@ -102,13 +115,11 @@ class ParsedFeed
            }
        }

-        $feed            = new static();
-        $feed->title     = self::rssValue($channel, 'title');
-        $feed->url       = $url;
-        $feed->updatedOn = Data::formatDate($updatedOn);
-        foreach ($channel->getElementsByTagName('item') as $item) $feed->items[] = ParsedItem::fromRSS($item);
-
-        return ['ok' => $feed];
+        return Result::OK(new self(
+            url:       $url,
+            title:     self::rssValue($channel, 'title'),
+            updatedOn: Data::formatDate($updatedOn),
+            items: array_map(ParsedItem::fromRSS(...), iterator_to_array($channel->getElementsByTagName('item')))));
    }

    /**
@ -118,10 +129,11 @@ class ParsedFeed
     * @param string $name The name of the attribute whose value should be obtained
     * @return string The attribute value if it exists, an empty string if not
     */
-    private static function attrValue(DOMNode $node, string $name): string {
+    private static function attrValue(DOMNode $node, string $name): string
+    {
        return ($node->hasAttributes() ? $node->attributes->getNamedItem($name)?->value : null) ?? '';
-
    }
+
    /**
     * Get the value of a child element by its tag name for an Atom feed
     *
@ -132,14 +144,15 @@ class ParsedFeed
     * @param string $tagName The name of the tag whose value should be obtained
     * @return string The value of the element (or "[element] not found" if that element does not exist)
     */
-    public static function atomValue(DOMNode $element, string $tagName): string {
+    public static function atomValue(DOMNode $element, string $tagName): string
+    {
        $tags = $element->getElementsByTagName($tagName);
-        if ($tags->length == 0) return "$tagName not found";
+        if ($tags->length === 0) return "$tagName not found";
        $tag = $tags->item(0);
        if (!($tag instanceof DOMElement)) return $tag->textContent;
        if (self::attrValue($tag, 'type') == 'xhtml') {
            $div = $tag->getElementsByTagNameNS(self::XHTML_NS, 'div');
-            if ($div->length == 0) return "-- invalid XHTML content --";
+            if ($div->length === 0) return "-- invalid XHTML content --";
            return $div->item(0)->textContent;
        }
        return $tag->textContent;
@ -150,103 +163,114 @@ class ParsedFeed
     *
     * @param DOMDocument $xml The XML received from the feed
     * @param string $url The actual URL for the feed
-     * @return array|Feed[] ['ok' => feed]
+     * @return Result<ParsedFeed, string> The feed (does not have any error handling)
     */
-    private static function fromAtom(DOMDocument $xml, string $url): array {
+    private static function fromAtom(DOMDocument $xml, string $url): Result
+    {
        $root = $xml->getElementsByTagNameNS(self::ATOM_NS, 'feed')->item(0);
        if (($updatedOn = self::atomValue($root, 'updated')) == 'pubDate not found') $updatedOn = null;

-        $feed            = new static();
-        $feed->title     = self::atomValue($root, 'title');
-        $feed->url       = $url;
-        $feed->updatedOn = Data::formatDate($updatedOn);
-        foreach ($root->getElementsByTagName('entry') as $entry) $feed->items[] = ParsedItem::fromAtom($entry);
-
-        return ['ok' => $feed];
+        return Result::OK(new self(
+            url:       $url,
+            title:     self::atomValue($root, 'title'),
+            updatedOn: Data::formatDate($updatedOn),
+            items: array_map(ParsedItem::fromAtom(...), iterator_to_array($root->getElementsByTagName('entry')))));
    }

    /**
     * Retrieve a document (http/https)
     *
     * @param string $url The URL of the document to retrieve
-     * @return array ['content' => document content, 'error' => error message, 'code' => HTTP response code,
-     *      'url' => effective URL]
+     * @return Result<array, string> ['content' => doc content, 'code' => HTTP response code, 'url' => effective URL] if
+     *      successful, an error message if not
     */
-    private static function retrieveDocument(string $url): array {
+    private static function retrieveDocument(string $url): Result
+    {
        $docReq = curl_init($url);
-        curl_setopt($docReq, CURLOPT_FOLLOWLOCATION, true);
-        curl_setopt($docReq, CURLOPT_RETURNTRANSFER, true);
-        curl_setopt($docReq, CURLOPT_CONNECTTIMEOUT, 5);
-        curl_setopt($docReq, CURLOPT_TIMEOUT,        15);
-        curl_setopt($docReq, CURLOPT_USERAGENT,      self::USER_AGENT);
+        try {
+            curl_setopt($docReq, CURLOPT_FOLLOWLOCATION, true);
+            curl_setopt($docReq, CURLOPT_RETURNTRANSFER, true);
+            curl_setopt($docReq, CURLOPT_CONNECTTIMEOUT, 5);
+            curl_setopt($docReq, CURLOPT_TIMEOUT, 15);
+            curl_setopt($docReq, CURLOPT_USERAGENT, self::USER_AGENT);

-        $result = [
-            'content' => curl_exec($docReq),
-            'error'   => curl_error($docReq),
-            'code'    => curl_getinfo($docReq, CURLINFO_RESPONSE_CODE),
-            'url'     => curl_getinfo($docReq, CURLINFO_EFFECTIVE_URL)
-        ];
+            $error = curl_error($docReq);
+            if ($error !== '') return Result::Error($error);

-        curl_close($docReq);
-        return $result;
+            return Result::OK([
+                'content' => curl_exec($docReq),
+                'code'    => curl_getinfo($docReq, CURLINFO_RESPONSE_CODE),
+                'url'     => curl_getinfo($docReq, CURLINFO_EFFECTIVE_URL)
+            ]);
+        } finally {
+            curl_close($docReq);
+        }
    }

    /**
     * Derive a feed URL from an HTML document
     *
     * @param string $content The HTML document content from which to derive a feed URL
-     * @return array|string[] ['ok' => feed URL] if successful, ['error' => message] if not
+     * @return Result<string, string> The feed URL if successful, an error message if not
     */
-    private static function deriveFeedFromHTML(string $content): array {
+    private static function deriveFeedFromHTML(string $content): Result
+    {
        $html = new DOMDocument();
        $html->loadHTML(substr($content, 0, strpos($content, '</head>') + 7));
        $headTags = $html->getElementsByTagName('head');
-        if ($headTags->length < 1) return ['error' => 'Cannot find feed at this URL'];
+        if ($headTags->length < 1) return Result::Error('Cannot find feed at this URL');
        $head = $headTags->item(0);
        foreach ($head->getElementsByTagName('link') as $link) {
-            if (self::attrValue($link, 'rel') == 'alternate') {
+            if (self::attrValue($link, 'rel') === 'alternate') {
                $type = self::attrValue($link, 'type');
-                if ($type == 'application/rss+xml' || $type == 'application/atom+xml') {
-                    return ['ok' => self::attrValue($link, 'href')];
+                if ($type === 'application/rss+xml' || $type === 'application/atom+xml') {
+                    return Result::OK(self::attrValue($link, 'href'));
                }
            }
        }
-        return ['error' => 'Cannot find feed at this URL'];
+        return Result::Error('Cannot find feed at this URL');
    }

    /**
     * Retrieve the feed
     *
     * @param string $url The URL of the feed to retrieve
-     * @return array|ParsedFeed[]|string[] ['ok' => feed] if successful, ['error' => message] if not
+     * @return Result<ParsedFeed, string> The feed if successful, an error message if not
     */
-    public static function retrieve(string $url): array {
-        $doc = self::retrieveDocument($url);
-
-        if ($doc['error'] != '') return ['error' => $doc['error']];
-        if ($doc['code'] != 200) {
-            return ['error' => "Prospective feed URL $url returned HTTP Code {$doc['code']}: {$doc['content']}"];
-        }
-
-        $start = strtolower(strlen($doc['content']) >= 9 ? substr($doc['content'], 0, 9) : $doc['content']);
-        if ($start == '<!doctype' || str_starts_with($start, '<html')) {
-            $derivedURL = self::deriveFeedFromHTML($doc['content']);
-            if (key_exists('error', $derivedURL)) return ['error' => $derivedURL['error']];
-            $feedURL = $derivedURL['ok'];
-            if (!str_starts_with($feedURL, 'http')) {
-                // Relative URL; feed should be retrieved in the context of the original URL
-                $original = parse_url($url);
-                $port     = key_exists('port', $original) ? ":{$original['port']}" : '';
-                $feedURL  = $original['scheme'] . '://' . $original['host'] . $port . $feedURL;
-            }
-            $doc = self::retrieveDocument($feedURL);
-        }
-
-        $parsed = self::parseFeed($doc['content']);
-        if (key_exists('error', $parsed)) return ['error' => $parsed['error']];
-
-        $extract = $parsed['ok']->getElementsByTagNameNS(self::ATOM_NS, 'feed')->length > 0
-            ? self::fromAtom(...) : self::fromRSS(...);
-        return $extract($parsed['ok'], $doc['url']);
+    public static function retrieve(string $url): Result
+    {
+        $doc = self::retrieveDocument($url)
+            ->bind(fn(array $doc) => match ($doc['code']) {
+                200     => Result::OK($doc),
+                default => Result::Error(
+                    "Prospective feed URL $url returned HTTP Code {$doc['code']}: {$doc['content']}"),
+            })
+            ->bind(function (array $doc) use ($url) {
+                $start = strtolower(strlen($doc['content']) >= 9 ? substr($doc['content'], 0, 9) : $doc['content']);
+                return $start === '<!doctype' || str_starts_with($start, '<html')
+                    ? self::deriveFeedFromHTML($doc['content'])
+                        ->bind(function (string $feedURL) use ($url) {
+                            if (!str_starts_with($feedURL, 'http')) {
+                                // Relative URL; feed should be retrieved in the context of the original URL
+                                $original = parse_url($url);
+                                $port     = key_exists('port', $original) ? ":{$original['port']}" : '';
+                                $feedURL  = $original['scheme'] . '://' . $original['host'] . $port . $feedURL;
+                            }
+                            return self::retrieveDocument($feedURL);
+                        })
+                        ->bind(fn($doc) => match ($doc['code']) {
+                            200     => Result::OK($doc),
+                            default => Result::Error(
+                                "Derived feed URL {$doc['url']} returned HTTP Code {$doc['code']}: {$doc['content']}"),
+                        })
+                    : Result::OK($doc);
+            });
+        return $doc
+            ->bind(fn($doc) => self::parseFeed($doc['content']))
+            ->bind(function (DOMDocument $parsed) use ($doc) {
+                $extract = $parsed->getElementsByTagNameNS(self::ATOM_NS, 'feed')->length > 0
+                    ? self::fromAtom(...) : self::fromRSS(...);
+                return $extract($parsed, $doc->getOK()['url']);
+            });
    }
 }
--- a/src/lib/ParsedItem.php
+++ b/src/lib/ParsedItem.php
@ -1,4 +1,10 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 namespace FeedReaderCentral;

@ -7,7 +13,7 @@ use DOMNode;
 /**
 * Information for a feed item
 */
-class ParsedItem
+readonly class ParsedItem
 {
    /**
     * Constructor
@ -27,24 +33,24 @@ class ParsedItem
     * Construct a feed item from an Atom feed's `<entry>` tag
     *
     * @param DOMNode $node The XML node from which a feed item should be constructed
-     * @return static A feed item constructed from the given node
+     * @return ParsedItem A feed item constructed from the given node
     */
-    public static function fromAtom(DOMNode $node): static
+    public static function fromAtom(DOMNode $node): self
    {
        $guid = ParsedFeed::atomValue($node, 'id');
        $link = '';
        foreach ($node->getElementsByTagName('link') as $linkElt) {
            if ($linkElt->hasAttributes()) {
                $relAttr = $linkElt->attributes->getNamedItem('rel');
-                if ($relAttr && $relAttr->value == 'alternate') {
+                if ($relAttr && $relAttr->value === 'alternate') {
                    $link = $linkElt->attributes->getNamedItem('href')->value;
                    break;
                }
            }
        }
-        if ($link == '' && str_starts_with($guid, 'http')) $link = $guid;
+        if ($link === '' && str_starts_with($guid, 'http')) $link = $guid;

-        return new static(
+        return new self(
            guid:        $guid,
            title:       ParsedFeed::atomValue($node, 'title'),
            link:        $link,
@ -57,15 +63,15 @@ class ParsedItem
     * Construct a feed item from an RSS feed's `<item>` tag
     *
     * @param DOMNode $node The XML node from which a feed item should be constructed
-     * @return static A feed item constructed from the given node
+     * @return ParsedItem A feed item constructed from the given node
     */
-    public static function fromRSS(DOMNode $node): static
+    public static function fromRSS(DOMNode $node): self
    {
        $itemGuid = ParsedFeed::rssValue($node, 'guid');
        $updNodes = $node->getElementsByTagNameNS(ParsedFeed::ATOM_NS,    'updated');
        $encNodes = $node->getElementsByTagNameNS(ParsedFeed::CONTENT_NS, 'encoded');

-        return new static(
+        return new self(
            guid:        $itemGuid == 'guid not found' ? ParsedFeed::rssValue($node, 'link') : $itemGuid,
            title:       ParsedFeed::rssValue($node, 'title'),
            link:        ParsedFeed::rssValue($node, 'link'),
--- a/src/lib/Security.php
+++ b/src/lib/Security.php
@ -1,49 +1,77 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 namespace FeedReaderCentral;

+use BitBadger\InspiredByFSharp\Option;
 use BitBadger\PDODocument\{DocumentException, Field, Patch};

 /**
 * Security functions
 */
-class Security
+readonly class Security
 {
    /** @var int Run as a single user requiring no password */
-    public const SINGLE_USER = 0;
+    public const SingleUserMode = 0;

    /** @var int Run as a single user requiring a password */
-    public const SINGLE_USER_WITH_PASSWORD = 1;
+    public const SingleUserPasswordMode = 1;

    /** @var int Require users to provide e-mail address and password */
+    public const MultiUserMode = 2;
+
+    /**
+     * @var int Run as a single user requiring no password
+     * @deprecated Use Security::SingleUserMode instead
+     */
+    public const SINGLE_USER = 0;
+
+    /**
+     * @var int Run as a single user requiring a password
+     * @deprecated Use Security::SingleUserPasswordMode instead
+     */
+    public const SINGLE_USER_WITH_PASSWORD = 1;
+
+    /**
+     * @var int Require users to provide e-mail address and password
+     * @deprecated Use Security::MultiUserMode instead
+     */
    public const MULTI_USER = 2;

    /** @var string The e-mail address for the single user */
-    public const SINGLE_USER_EMAIL = 'solouser@example.com';
+    public const SingleUserEmail = 'solouser@example.com';

    /** @var string The password for the single user with no password */
-    public const SINGLE_USER_PASSWORD = 'no-password-required';
+    public const SingleUserPassword = 'no-password-required';

    /** @var string The password algorithm to use for our passwords */
-    public const PW_ALGORITHM = PASSWORD_DEFAULT;
+    public const PasswordAlgorithm = PASSWORD_DEFAULT;
+
+    /** Prevent instances of this class */
+    private function __construct() {}

    /**
     * Verify a user's password
     *
     * @param User $user The user information retrieved from the database
     * @param string $password The password provided by the user
-     * @param string|null $returnTo The URL to which the user should be redirected
+     * @param Option<string> $returnTo The URL to which the user should be redirected
     * @throws DocumentException if any is encountered
     */
-    private static function verifyPassword(User $user, string $password, ?string $returnTo): void
+    private static function verifyPassword(User $user, string $password, Option $returnTo): void
    {
        if (password_verify($password, $user->password)) {
-            if (password_needs_rehash($user->password, self::PW_ALGORITHM)) {
-                Patch::byId(Table::USER, $user->id, ['password' => password_hash($password, self::PW_ALGORITHM)]);
+            if (password_needs_rehash($user->password, self::PasswordAlgorithm)) {
+                Patch::byId(Table::User, $user->id, ['password' => password_hash($password, self::PasswordAlgorithm)]);
            }
-            $_SESSION[Key::USER_ID]    = $user->id;
-            $_SESSION[Key::USER_EMAIL] = $user->email;
-            frc_redirect($returnTo ?? '/');
+            $_SESSION[Key::UserId]    = $user->id;
+            $_SESSION[Key::UserEmail] = $user->email;
+            frc_redirect($returnTo->getOrDefault('/'));
        }
    }

@ -52,21 +80,21 @@ class Security
     *
     * @param string $email The e-mail address for the user (cannot be the single-user mode user)
     * @param string $password The password provided by the user
-     * @param string|null $returnTo The URL to which the user should be redirected
+     * @param Option<string> $returnTo The URL to which the user should be redirected
     * @throws DocumentException If any is encountered
     */
-    public static function logOnUser(string $email, string $password, ?string $returnTo): void {
-        if (SECURITY_MODEL == self::SINGLE_USER_WITH_PASSWORD) {
-            $dbEmail = self::SINGLE_USER_EMAIL;
+    public static function logOnUser(string $email, string $password, Option $returnTo): void
+    {
+        if (SECURITY_MODEL === self::SingleUserPasswordMode) {
+            $dbEmail = self::SingleUserEmail;
        } else {
-            if ($email == self::SINGLE_USER_EMAIL) {
+            if ($email === self::SingleUserEmail) {
                add_error('Invalid credentials; log on unsuccessful');
                return;
            }
            $dbEmail = $email;
        }
-        $user = User::findByEmail($dbEmail);
-        if ($user) self::verifyPassword($user, $password, $returnTo);
+        User::findByEmail($dbEmail)->iter(fn(User $it) => self::verifyPassword($it, $password, $returnTo));
        add_error('Invalid credentials; log on unsuccessful');
    }

@ -77,9 +105,10 @@ class Security
     * @param string $password The new password for this user
     * @throws DocumentException If any is encountered
     */
-    public static function updatePassword(string $email, string $password): void {
-        Patch::byFields(Table::USER, [Field::EQ('email', $email)],
-            ['password' => password_hash($password, self::PW_ALGORITHM)]);
+    public static function updatePassword(string $email, string $password): void
+    {
+        Patch::byFields(Table::User, [Field::EQ('email', $email)],
+            ['password' => password_hash($password, self::PasswordAlgorithm)]);
    }

    /**
@ -87,13 +116,13 @@ class Security
     *
     * @throws DocumentException If any is encountered
     */
-    private static function logOnSingleUser(): void {
-        $user = User::findByEmail(self::SINGLE_USER_EMAIL);
-        if (!$user) {
-            User::add(self::SINGLE_USER_EMAIL, self::SINGLE_USER_PASSWORD);
-            $user = User::findByEmail(self::SINGLE_USER_EMAIL);
-        }
-        self::verifyPassword($user, self::SINGLE_USER_PASSWORD, $_GET['returnTo']);
+    private static function logOnSingleUser(): void
+    {
+        $user = User::findByEmail(self::SingleUserEmail)->getOrCall(function () {
+            User::add(self::SingleUserEmail, self::SingleUserPassword);
+            return User::findByEmail(self::SingleUserEmail)->get();
+        });
+        self::verifyPassword($user, self::SingleUserPassword, $_GET['returnTo']);
    }

    /**
@ -102,12 +131,13 @@ class Security
     * @param bool $redirectIfAnonymous Whether to redirect the request if there is no user logged on
     * @throws DocumentException If any is encountered
     */
-    public static function verifyUser(bool $redirectIfAnonymous = true): void {
-        if (key_exists(Key::USER_ID, $_SESSION)) return;
+    public static function verifyUser(bool $redirectIfAnonymous = true): void
+    {
+        if (key_exists(Key::UserId, $_SESSION)) return;

-        if (SECURITY_MODEL == self::SINGLE_USER) self::logOnSingleUser();
+        if (SECURITY_MODEL === self::SingleUserMode) self::logOnSingleUser();

-        if (SECURITY_MODEL != self::SINGLE_USER_WITH_PASSWORD && SECURITY_MODEL != self::MULTI_USER) {
+        if (SECURITY_MODEL !== self::SingleUserPasswordMode && SECURITY_MODEL != self::MultiUserMode) {
            die('Unrecognized security model (' . SECURITY_MODEL . ')');
        }

--- a/src/lib/Table.php
+++ b/src/lib/Table.php
@ -1,18 +1,27 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 namespace FeedReaderCentral;

 /**
 * Constants to use when accessing tables
 */
-class Table
+readonly class Table
 {
    /** @var string The user table */
-    public const USER = 'frc_user';
+    public const User = 'frc_user';

    /** @var string The feed table */
-    public const FEED = 'feed';
+    public const Feed = 'feed';

    /** @var string The item table */
-    public const ITEM = 'item';
+    public const Item = 'item';
+
+    /** Prevent instances of this class */
+    private function __construct() {}
 }
--- a/src/lib/User.php
+++ b/src/lib/User.php
@ -1,7 +1,14 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 namespace FeedReaderCentral;

+use BitBadger\InspiredByFSharp\Option;
 use BitBadger\PDODocument\{Custom, Document, DocumentException, Field, Find, Parameters, Query};
 use BitBadger\PDODocument\Mapper\ExistsMapper;

@ -23,12 +30,12 @@ class User
     * Find a user by their e=mail address
     *
     * @param string $email The e-mail address of the user to retrieve
-     * @return User|false The user information, or null if the user is not found
+     * @return Option<User> A `Some` value with the user information if found, `None` otherwise
     * @throws DocumentException If any is encountered
     */
-    public static function findByEmail(string $email): User|false
+    public static function findByEmail(string $email): Option
    {
-        return Find::firstByFields(Table::USER, [Field::EQ('email', $email)], User::class);
+        return Find::firstByFields(Table::User, [Field::EQ('email', $email)], User::class);
    }

    /**
@ -40,7 +47,7 @@ class User
     */
    public static function add(string $email, string $password): void
    {
-        Document::insert(Table::USER, new User(email: $email, password: $password));
+        Document::insert(Table::User, new User(email: $email, password: $password));
    }

    /**
@ -51,7 +58,7 @@ class User
     */
    public static function hasBookmarks(): bool
    {
-        $fields = [Data::userIdField(Table::FEED), Data::bookmarkField(true, Table::ITEM)];
+        $fields = [Data::userIdField(Table::Feed), Data::bookmarkField(true, Table::Item)];
        return Custom::scalar(Query\Exists::query(ItemWithFeed::FROM_WITH_JOIN, Query::whereByFields($fields)),
            Parameters::addFields($fields, []), new ExistsMapper());
    }
--- a/src/public/bookmark.php
+++ b/src/public/bookmark.php
@ -1,11 +1,16 @@
-<?php declare(strict_types=1);
-
+<?php
 /**
 * Bookmark Partial Handler
 *
 * This will display a button which will either add or remove a bookmark for a given item.
+ *
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
 */

+declare(strict_types=1);
+
+use BitBadger\InspiredByFSharp\Option;
 use BitBadger\PDODocument\{DocumentException, Patch};
 use FeedReaderCentral\{ItemWithFeed, Table};

@ -13,24 +18,22 @@ include '../start.php';

 FeedReaderCentral\Security::verifyUser();

-$id = key_exists('id', $_GET) ? (int)$_GET['id'] : -1;
-
-if (!$item = ItemWithFeed::retrieveById($id)) not_found();
+$id   = key_exists('id', $_GET) ? (int)$_GET['id'] : -1;
+$item = ItemWithFeed::retrieveById($id)->getOrCall(not_found(...));

 if (key_exists('action', $_GET)) {
-    $flag = match ($_GET['action']) {
-        'add'    => 1,
-        'remove' => 0,
-        default  => null
-    };
-    if (isset($flag)) {
+    (match ($_GET['action']) {
+        'add'    => Option::Some(1),
+        'remove' => Option::Some(0),
+        default  => Option::None(),
+    })->iter(function (int $flag) use ($id, &$item) {
        try {
-            Patch::byId(Table::ITEM, $id, ['is_bookmarked' => $flag]);
+            Patch::byId(Table::Item, $id, ['is_bookmarked' => $flag]);
            $item->is_bookmarked = $flag;
        } catch (DocumentException $ex) {
            add_error("$ex");
        }
-    }
+    });
 }

 $action = $item->isBookmarked() ? 'remove' : 'add';
--- a/src/public/docs/feeds.php
+++ b/src/public/docs/feeds.php
@ -1,4 +1,10 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 include '../../start.php';

--- a/src/public/docs/index.php
+++ b/src/public/docs/index.php
@ -1,4 +1,10 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 include '../../start.php';

--- a/src/public/docs/items.php
+++ b/src/public/docs/items.php
@ -1,4 +1,10 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 include '../../start.php';

--- a/src/public/docs/security-modes.php
+++ b/src/public/docs/security-modes.php
@ -1,4 +1,10 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 include '../../start.php';

@ -38,7 +44,7 @@ page_head('Security Modes | Documentation'); ?>
    <p>In Single-User mode, the application uses a known e-mail address and password to mimic multi-user mode where that
        user is always logged on. If you have been using the application this way, and decide that you want to run in
        multi-user mode instead, you will need to update <code>SECURITY_MODEL</code> in <code>user-config.php</code> to
-        <code>Security::MULTI_USER</code>.
+        <code>Security::MultiUserMode</code>.
    <p>The e-mail address used for Single-User mode is not allowed to log on in Multi-User mode. If you want to preserve
        the feeds defined by the single user, use the CLI to replace its e-mail address and password.
    <p><code>php-cli utils/user.php migrate-single-user dave@example.com Dav3sPas$wort</code>
@ -49,13 +55,13 @@ page_head('Security Modes | Documentation'); ?>
        displays feeds from the Single-User mode user. The information for the other users remains in the database,
        though, so this change is not destructive.
    <h2 id=change-single-to-pw>Changing from Single-User to Single-User with Password Mode</h2>
-    <p>Set <code>SECURITY_MODEL</code> in <code>user-config.php</code> to
-        <code>Security::SINGLE_USER_WITH_PASSWORD</code>, then use the <code>user</code> CLI utility to set a password.
+    <p>Set <code>SECURITY_MODEL</code> in <code>user-config.php</code> to <code>Security::SingleUserPasswordMode</code>,
+        then use the <code>user</code> CLI utility to set a password.
    <p><code>php-cli util/user.php set-single-password aNiceC0mplexPassw0rd</code>
    <h2 id=change-pw-to-single>Changing from Single-User with Password to Single-User Mode</h2>
    <p>If you decide you do not want to enter a password, but want to maintain single-user mode, set
-        <code>SECURITY_MODEL</code> in <code>user-config.php</code> to <code>Security::SINGLE_USER</code>, then run the
-        <code>user</code> CLI utility to reset the single user back to its expected default.
+        <code>SECURITY_MODEL</code> in <code>user-config.php</code> to <code>Security::SingleUserMode</code>, then run
+        the <code>user</code> CLI utility to reset the single user back to its expected default.
    <p><code>php-cli util/user.php reset-single-password</code>
 </article><?php
 page_foot();
--- a/src/public/docs/the-cli.php
+++ b/src/public/docs/the-cli.php
@ -1,4 +1,10 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 include '../../start.php';

--- a/src/public/feed/index.php
+++ b/src/public/feed/index.php
@ -1,11 +1,16 @@
-<?php declare(strict_types=1);
-
+<?php
 /**
 * Add/Edit/Delete Feed Page
 *
 * Allows users to add, edit, and delete feeds
+ *
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
 */

+declare(strict_types=1);
+
+use BitBadger\InspiredByFSharp\Result;
 use BitBadger\PDODocument\{Delete, DocumentException, Field};
 use FeedReaderCentral\{Feed, Security, Table};

@ -15,39 +20,40 @@ Security::verifyUser();

 $feedId = key_exists('id', $_GET) ? (int)$_GET['id'] : -1;

-if ($_SERVER['REQUEST_METHOD'] == 'DELETE') {
-    try {
-        if (!($feed = Feed::retrieveById($feedId))) not_found();
-        Delete::byFields(Table::ITEM, [Field::EQ('feed_id', $feed->id)]);
-        Delete::byId(Table::FEED, $feed->id);
-        add_info('Feed &ldquo;' . htmlentities($feed->title) . '&rdquo; deleted successfully');
-        frc_redirect('/feeds');
-    } catch (DocumentException $ex) {
-        add_error("$ex");
-    }
-}
-
-if ($_SERVER['REQUEST_METHOD'] == 'POST') {
-    try {
-        $isNew = $_POST['id'] == '-1';
-        if ($isNew) {
-            $result = Feed::add($_POST['url']);
-        } else {
-            $feedId = (int)$_POST['id'];
-            $toEdit = Feed::retrieveById($feedId);
-            $result = $toEdit
-                ? Feed::update($toEdit, $_POST['url'])
-                : ['error' => "Feed $feedId not found"];
-        }
-        if (key_exists('ok', $result)) {
-            add_info('Feed saved successfully');
+switch ($_SERVER['REQUEST_METHOD']) {
+    case 'DELETE':
+        try {
+            $feed = Feed::retrieveById($feedId)->getOrCall(not_found(...));
+            Delete::byFields(Table::Item, [Field::EQ('feed_id', $feed->id)]);
+            Delete::byId(Table::Feed, $feed->id);
+            add_info('Feed &ldquo;' . htmlentities($feed->title) . '&rdquo; deleted successfully');
            frc_redirect('/feeds');
+        } catch (DocumentException $ex) {
+            add_error("$ex");
        }
-        add_error($result['error']);
-        $feedId = 'error';
-    } catch (DocumentException $ex) {
-        add_error("$ex");
-    }
+        break;
+
+    case 'POST':
+        try {
+            if ((int)$_POST['id'] === -1) {
+                $result = Feed::add($_POST['url']);
+            } else {
+                $feedId = (int)$_POST['id'];
+                $toEdit = Feed::retrieveById($feedId);
+                $result = $toEdit->isSome()
+                    ? Feed::update($toEdit->get(), $_POST['url'])
+                    : Result::Error("Feed $feedId not found");
+            }
+            $result->iter(function () {
+                add_info('Feed saved successfully');
+                frc_redirect('/feeds');
+            });
+            add_error($result->getError());
+            $feedId = 'error';
+        } catch (DocumentException $ex) {
+            add_error("$ex");
+        }
+        break;
 }

 if ($feedId == -1) {
@ -55,9 +61,9 @@ if ($feedId == -1) {
    $feed  = new Feed(id: -1);
 } else {
    $title = 'Edit RSS Feed';
-    if ($feedId == 'error') {
-        $feed = new Feed(id: (int)$_POST['id'], url: $_POST['url'] ?? '');
-    } elseif (!($feed = Feed::retrieveById((int)$feedId))) not_found();
+    $feed = $feedId == 'error'
+        ? new Feed(id: (int)$_POST['id'], url: $_POST['url'] ?? '')
+        : Feed::retrieveById((int)$feedId)->getOrCall(not_found(...));
 }

 page_head($title); ?>
--- a/src/public/feed/items.php
+++ b/src/public/feed/items.php
@ -1,19 +1,23 @@
-<?php declare(strict_types=1);
-
+<?php
 /**
 * Feed Item List Page
 *
 * Lists items in a given feed (all, unread, or bookmarked)
+ *
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
 */

+declare(strict_types=1);
+
 use FeedReaderCentral\{Feed, ItemList};

 include '../../start.php';

 FeedReaderCentral\Security::verifyUser();

-$id = key_exists('id', $_GET) ? (int)$_GET['id'] : -1;
-if (!($feed = Feed::retrieveById($id))) not_found();
+$id   = key_exists('id', $_GET) ? (int)$_GET['id'] : -1;
+$feed = Feed::retrieveById($id)->getOrCall(not_found(...));

 $list = match (true) {
    key_exists('unread',     $_GET) => ItemList::unreadForFeed($feed->id),
@ -21,8 +25,8 @@ $list = match (true) {
    default                         => ItemList::allForFeed($feed->id)
 };

-page_head(($list->itemType != '' ? "$list->itemType Items | " : '') . strip_tags($feed->title));
-if ($list->itemType == '') {
+page_head(($list->itemType === '' ? '' : "$list->itemType Items | ") . strip_tags($feed->title));
+if ($list->itemType === '') {
    echo '<h1>' . htmlentities($feed->title) . '</h1>';
 } else {
    echo '<h1 class=item_heading>' . htmlentities($feed->title) . '</h1>';
--- a/src/public/feeds.php
+++ b/src/public/feeds.php
@ -1,11 +1,15 @@
-<?php declare(strict_types=1);
-
+<?php
 /**
 * Feed Maintenance Page
 *
 * List feeds and provide links for maintenance actions
+ *
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
 */

+declare(strict_types=1);
+
 use BitBadger\PDODocument\{Custom, Field, Query};
 use BitBadger\PDODocument\Mapper\{ArrayMapper, DocumentMapper};
 use FeedReaderCentral\{Feed, Key, Table};
@ -14,19 +18,19 @@ include '../start.php';

 FeedReaderCentral\Security::verifyUser();

-$field = Field::EQ('user_id', $_SESSION[Key::USER_ID], ':user');
-$feeds = Custom::list(Query\Find::byFields(Table::FEED, [$field]) . " ORDER BY lower(data->>'title')",
+$field = Field::EQ('user_id', $_SESSION[Key::UserId], ':user');
+$feeds = Custom::list(Query\Find::byFields(Table::Feed, [$field]) . " ORDER BY lower(data->>'title')",
    $field->appendParameter([]), new DocumentMapper(Feed::class));

 page_head('Your Feeds');
 echo '<h1>Your Feeds</h1><article><p class=action_buttons>' . hx_get('/feed/?id=-1', 'Add Feed') . '</p>';
-foreach ($feeds->items() as /** @var Feed $feed */ $feed) {
-    $item   = Table::ITEM;
+$feeds->iter(function (Feed $feed) {
+    $item   = Table::Item;
    $counts = Custom::single(<<<SQL
        SELECT (SELECT COUNT(*) FROM $item WHERE data->>'feed_id' = :feed)                                AS total,
               (SELECT COUNT(*) FROM $item WHERE data->>'feed_id' = :feed AND data->>'is_read'       = 0) AS unread,
               (SELECT COUNT(*) FROM $item WHERE data->>'feed_id' = :feed AND data->>'is_bookmarked' = 1) AS marked
-        SQL, [':feed' => $feed->id], new ArrayMapper()) ?? ['total' => 0, 'unread' => 0, 'marked' => 0];
+        SQL, [':feed' => $feed->id], new ArrayMapper())->getOrDefault(['total' => 0, 'unread' => 0, 'marked' => 0]);
    echo '<p><strong>' . htmlentities($feed->title) . '</strong><br>'
        . '<span class=meta><em>Last Updated ' . date_time($feed->updated_on) . ' &bull; '
        . 'As of ' . date_time($feed->checked_on) . '</em><br>' . hx_get("/feed/?id=$feed->id", 'Edit') . ' &bull; '
@ -39,6 +43,6 @@ foreach ($feeds->items() as /** @var Feed $feed */ $feed) {
            . ' hx-confirm="Are you sure you want to delete &ldquo;' . htmlspecialchars($feed->title)
                . '&rdquo;? This will remove the feed and all its items, including unread and bookmarked.">Delete</a>'
        . '</span>';
-}
+});
 echo '</article>';
 page_foot();
--- a/src/public/index.php
+++ b/src/public/index.php
@ -1,11 +1,15 @@
-<?php declare(strict_types=1);
-
+<?php
 /**
 * Home Page
 *
 * Displays a list of unread or bookmarked items for the current user
+ *
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
 */

+declare(strict_types=1);
+
 use FeedReaderCentral\{Feed, ItemList};

 include '../start.php';
@ -14,16 +18,16 @@ FeedReaderCentral\Security::verifyUser();

 if (key_exists('refresh', $_GET)) {
    $refreshResult = Feed::refreshAll();
-    if (key_exists('ok', $refreshResult)) {
+    if ($refreshResult->isOK()) {
        add_info('All feeds refreshed successfully');
    } else {
-        add_error(nl2br($refreshResult['error']));
+        add_error(nl2br($refreshResult->getError()));
    }
 }

 $list = match (true) {
    key_exists('bookmarked', $_GET) => ItemList::allBookmarked(),
-    default                         => ItemList::allUnread()
+    default                         => ItemList::allUnread(),
 };
 $title = "Your $list->itemType Items";

--- a/src/public/item.php
+++ b/src/public/item.php
@ -1,11 +1,15 @@
-<?php declare(strict_types=1);
-
+<?php
 /**
 * Item View Page
 *
 * Retrieves and displays an item from a feed belonging to the current user
+ *
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
 */

+declare(strict_types=1);
+
 use BitBadger\PDODocument\{Delete, DocumentException, Patch};
 use FeedReaderCentral\{ItemWithFeed, Table};

@ -16,35 +20,38 @@ FeedReaderCentral\Security::verifyUser();
 $id = match (true) {
    key_exists('id', $_POST) => (int)$_POST['id'],
    key_exists('id', $_GET)  => (int)$_GET['id'],
-    default                  => -1
+    default                  => -1,
+};
+$from = match ($_SERVER['REQUEST_METHOD']) {
+    'POST'  => $_POST['from'],
+    default => $_GET['from'] ?? '/',
 };

-if ($_SERVER['REQUEST_METHOD'] == 'POST') {
-    try {
-        // "Keep as New" button sends a POST request to reset the is_read flag before going back to the item list
-        if (ItemWithFeed::existsById($id)) {
-            Patch::byId(Table::ITEM, $id, ['is_read' => 0]);
+switch ($_SERVER['REQUEST_METHOD']) {
+    case 'POST':
+        try {
+            // "Keep as New" button sends a POST request to reset the is_read flag before going back to the item list
+            if (ItemWithFeed::existsById($id)) {
+                Patch::byId(Table::Item, $id, ['is_read' => 0]);
+            }
+            frc_redirect($from);
+        } catch (DocumentException $ex) {
+            add_error("$ex");
        }
-        frc_redirect($_POST['from']);
-    } catch (DocumentException $ex) {
-        add_error("$ex");
-    }
+        break;
+
+    case 'DELETE':
+        try {
+            if (ItemWithFeed::existsById($id)) Delete::byId(Table::Item, $id);
+        } catch (DocumentException $ex) {
+            add_error("$ex");
+        }
+        frc_redirect($from);
 }

-$from = $_GET['from'] ?? '/';
-
-if ($_SERVER['REQUEST_METHOD'] == 'DELETE') {
-    try {
-        if (ItemWithFeed::existsById($id)) Delete::byId(Table::ITEM, $id);
-    } catch (DocumentException $ex) {
-        add_error("$ex");
-    }
-    frc_redirect($from);
-}
-
-if (!$item = ItemWithFeed::retrieveById($id)) not_found();
+$item = ItemWithFeed::retrieveById($id)->getOrCall(not_found(...));
 try {
-    Patch::byId(Table::ITEM, $id, ['is_read' => 1]);
+    Patch::byId(Table::Item, $id, ['is_read' => 1]);
 } catch (DocumentException $ex) {
    add_error("$ex");
 }
--- a/src/public/search.php
+++ b/src/public/search.php
@ -1,11 +1,15 @@
-<?php declare(strict_types=1);
-
+<?php
 /**
 * Item Search Page
 *
 * Search for items across all feeds
+ *
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
 */

+declare(strict_types=1);
+
 include '../start.php';

 FeedReaderCentral\Security::verifyUser();
@ -13,8 +17,8 @@ FeedReaderCentral\Security::verifyUser();
 $search = $_GET['search'] ?? '';
 $items  = $_GET['items']  ?? 'all';

-if ($search != '') {
-    $list = FeedReaderCentral\ItemList::matchingSearch($search, $items == 'bookmarked');
+if ($search !== '') {
+    $list = FeedReaderCentral\ItemList::matchingSearch($search, $items === 'bookmarked');
 }

 page_head('Item Search'); ?>
@ -28,8 +32,8 @@ page_head('Item Search'); ?>
        <label>
            Items to Search
            <select name=items>
-                <option value=all <?=$items == 'all' ? ' selected' : ''?>>All</option>
-                <option value=bookmarked <?=$items == 'bookmarked' ? ' selected' : ''?>>Bookmarked</option>
+                <option value=all <?=$items === 'all' ? ' selected' : ''?>>All</option>
+                <option value=bookmarked <?=$items === 'bookmarked' ? ' selected' : ''?>>Bookmarked</option>
            </select>
        </label>
        <span class=break></span>
--- a/src/public/user/log-off.php
+++ b/src/public/user/log-off.php
@ -1,11 +1,15 @@
-<?php declare(strict_types=1);
-
+<?php
 /**
 * User Log Off Page
+ *
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
 */

+declare(strict_types=1);
+
 include '../../start.php';

-if (key_exists(FeedReaderCentral\Key::USER_ID, $_SESSION)) session_destroy();
+if (key_exists(FeedReaderCentral\Key::UserId, $_SESSION)) session_destroy();

 frc_redirect('/');
--- a/src/public/user/log-on.php
+++ b/src/public/user/log-on.php
@ -1,34 +1,39 @@
-<?php declare(strict_types=1);
-
+<?php
 /**
 * User Log On Page
 *
 * Accepts the user's e-mail address (multi-user) and password (multi-user or single-user-with-password) and attempts
 * to log them on to Feed Reader Central
+ *
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
 */

+declare(strict_types=1);
+
 include '../../start.php';

+use BitBadger\InspiredByFSharp\Option;
 use FeedReaderCentral\{Key, Security};

 Security::verifyUser(redirectIfAnonymous: false);

 // Users already logged on have no need of this page
-if (key_exists(Key::USER_ID, $_SESSION)) frc_redirect('/');
+if (key_exists(Key::UserId, $_SESSION)) frc_redirect('/');

-if ($_SERVER['REQUEST_METHOD'] == 'POST') {
-    Security::logOnUser($_POST['email'] ?? '', $_POST['password'], $_POST['returnTo'] ?? null);
+if ($_SERVER['REQUEST_METHOD'] === 'POST') {
+    Security::logOnUser($_POST['email'] ?? '', $_POST['password'], Option::of($_POST['returnTo'] ?? null));
    // If we're still here, something didn't work; preserve the returnTo parameter
    $_GET['returnTo'] = $_POST['returnTo'];
 }

-$isSingle = SECURITY_MODEL == Security::SINGLE_USER_WITH_PASSWORD;
+$isSingle = SECURITY_MODEL === Security::SingleUserPasswordMode;

 page_head('Log On'); ?>
 <h1>Log On</h1>
 <article>
    <form method=POST action=/user/log-on><?php
-        if (($_GET['returnTo'] ?? '') != '') { ?>
+        if (($_GET['returnTo'] ?? '') !== '') { ?>
            <input type=hidden name=returnTo value="<?=$_GET['returnTo']?>"><?php
        }
        if (!$isSingle) { ?>
--- a/src/start.php
+++ b/src/start.php
@ -1,4 +1,14 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * Web Request Start Script
+ *
+ * This loads the environment needed for a web request
+ *
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 use BitBadger\PDODocument\Configuration;
 use FeedReaderCentral\{Key, Security, User};
@ -19,8 +29,8 @@ session_start([
 */
 function add_message(string $level, string $message): void
 {
-    if (!key_exists(Key::USER_MSG, $_SESSION)) $_SESSION[Key::USER_MSG] = array();
-    $_SESSION[Key::USER_MSG][] = ['level' => $level, 'message' => $message];
+    if (!key_exists(Key::UserMsg, $_SESSION)) $_SESSION[Key::UserMsg] = [];
+    $_SESSION[Key::UserMsg][] = ['level' => $level, 'message' => $message];
 }

 /**
@ -43,7 +53,7 @@ function add_info(string $message): void
    add_message('INFO', $message);
 }

-/** @var bool $is_htmx True if this request was initiated by htmx, false if not */
+/** True if this request was initiated by htmx, false if not */
 $is_htmx = key_exists('HTTP_HX_REQUEST', $_SERVER) && !key_exists('HTTP_HX_HISTORY_RESTORE_REQUEST', $_SERVER);

 /**
@ -67,14 +77,14 @@ function title_bar(): void
    echo "<header hx-target=#main hx-push-url=true>"
        . "<div><a href=/ class=title>Feed Reader Central</a><span class=version>$version</span></div>"
        . "<nav>";
-    if (key_exists(Key::USER_ID, $_SESSION)) {
+    if (key_exists(Key::UserId, $_SESSION)) {
        nav_link(hx_get('/feeds', 'Feeds'), true);
        if (User::hasBookmarks()) nav_link(hx_get('/?bookmarked', 'Bookmarked'));
        nav_link(hx_get('/search', 'Search'));
        nav_link(hx_get('/docs/', 'Docs'));
        nav_link('<a href=/user/log-off>Log Off</a>');
-        if ($_SESSION[Key::USER_EMAIL] != Security::SINGLE_USER_EMAIL) {
-            nav_link($_SESSION[Key::USER_EMAIL]);
+        if ($_SESSION[Key::UserEmail] !== Security::SingleUserEmail) {
+            nav_link($_SESSION[Key::UserEmail]);
        }
    } else {
        nav_link(hx_get('/user/log-on', 'Log On'), true);
@ -100,15 +110,15 @@ function page_head(string $title): void
    }
    echo '</head><body>';
    if (!$is_htmx) title_bar();
-    if (sizeof($messages = $_SESSION[Key::USER_MSG] ?? []) > 0) {
+    if (sizeof($messages = $_SESSION[Key::UserMsg] ?? []) > 0) {
        echo '<div class=user_messages>';
            array_walk($messages, function ($msg) {
                echo '<div class=user_message>'
-                    . ($msg['level'] == 'INFO' ? '' : "<strong>{$msg['level']}</strong><br>")
+                    . ($msg['level'] === 'INFO' ? '' : "<strong>{$msg['level']}</strong><br>")
                    . $msg['message'] . '</div>';
            });
        echo '</div>';
-        $_SESSION[Key::USER_MSG] = [];
+        $_SESSION[Key::UserMsg] = [];
    }
 }

@ -164,7 +174,7 @@ function date_time(string $value): string
 */
 function hx_get(string $url, string $text, string $extraAttrs = ''): string
 {
-    $attrs = $extraAttrs != '' ? " $extraAttrs" : '';
+    $attrs = $extraAttrs !== '' ? " $extraAttrs" : '';
    return "<a href=\"$url\" hx-get=\"$url\"$attrs>$text</a>";
 }

--- a/src/user-config.dist.php
+++ b/src/user-config.dist.php
@ -12,11 +12,11 @@ use FeedReaderCentral\{Feed, Security};

 /**
 * Which security model should the application use? Options are:
- * - Security::SINGLE_USER (no e-mail required, does not require a password)
- * - Security::SINGLE_USER_WITH_PASSWORD (no e-mail required, does require a password)
- * - Security::MULTI_USER (e-mail and password required for all users)
+ * - Security::SingleUserMode (no e-mail required, does not require a password)
+ * - Security::SingleUserPasswordMode (no e-mail required, does require a password)
+ * - Security::MultiUserMode (e-mail and password required for all users)
 */
-const SECURITY_MODEL = 'CONFIGURE_ME';
+const SECURITY_MODEL = 'ConfigureMe';

 /** The name of the database file where users and feeds should be kept */
 const DATABASE_NAME = 'frc.db';
@ -30,12 +30,12 @@ const DATE_TIME_FORMAT = 'F j, Y \a\t g:ia';

 /**
 * How should item purging be done? (Purging never applies to bookmarked items.) Options are:
- * - Feed::PURGE_NONE - Do not purge items
- * - Feed::PURGE_READ - Purge all read items whenever purging is run (will not purge unread items)
- * - Feed::PURGE_BY_DAYS - Purge read and unread items older than a number of days (PURGE_NUMBER below)
- * - Feed::PURGE_BY_COUNT - Purge read and unread items beyond the number to keep (PURGE_NUMBER below)
+ * - Feed::PurgeNone - Do not purge items
+ * - Feed::PurgeRead - Purge all read items whenever purging is run (will not purge unread items)
+ * - Feed::PurgeByDays - Purge read and unread items older than a number of days (PURGE_NUMBER below)
+ * - Feed::PurgeByCount - Purge read and unread items beyond the number to keep (PURGE_NUMBER below)
 */
-const PURGE_TYPE = Feed::PURGE_BY_DAYS;
+const PURGE_TYPE = Feed::PurgeByDays;

 /**
 * For purge-by-days, how many days of items should be kept; for purge-by-count, how many items should be kept
--- a/src/util/db-update.php
+++ b/src/util/db-update.php
@ -1,4 +1,16 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * Alpha 7 -> Beta 1 Database Update Utility
+ *
+ * Between these two versions, the data format changed; this utility migrates existing data to its new format.
+ *
+ * _It will be removed in v1.1._
+ *
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 use BitBadger\PDODocument\{Custom, Document, DocumentException};
 use BitBadger\PDODocument\Mapper\{ArrayMapper, ExistsMapper};
@ -8,8 +20,6 @@ require __DIR__ . '/../cli-start.php';

 cli_title('DATABASE UPDATE');

-//const PDO_DOC_DEBUG_SQL = true;
-
 if ($argc < 2) display_help();

 switch ($argv[1]) {
@ -41,7 +51,8 @@ function display_help(): never
 function json_column_exists(): bool
 {
    try {
-        $table = Custom::single("SELECT sql FROM sqlite_master WHERE tbl_name='frc_user'", [], new ArrayMapper());
+        $table = Custom::single("SELECT sql FROM sqlite_master WHERE tbl_name='frc_user'", [], new ArrayMapper())
+            ->getOrDefault(['sql' => '']);
        return $table && substr_compare(strtolower($table['sql']), 'data text not null', 0) >= 0;
    } catch (DocumentException $ex) {
        printfn("ERR $ex");
@ -80,13 +91,13 @@ function run_update(): void
        $users = Custom::list('SELECT * FROM old_user', [], new ArrayMapper());
        if (!$users->hasItems()) throw new DocumentException('Could not retrieve users');
        foreach ($users->items() as $user) {
-            Document::insert(Table::USER, new User($user['id'], $user['email'], $user['password']));
+            Document::insert(Table::User, new User($user['id'], $user['email'], $user['password']));
        }
        printfn('Migrating feeds...');
        $feeds = Custom::list('SELECT * FROM old_feed', [], new ArrayMapper());
        if (!$feeds->hasItems()) throw new DocumentException('Could not retrieve feeds');
        foreach ($feeds->items() as $feed) {
-            Document::insert(Table::FEED,
+            Document::insert(Table::Feed,
                new Feed($feed['id'], $feed['user_id'], $feed['url'], $feed['title'], $feed['updated_on'],
                    $feed['checked_on']));
        }
@ -94,7 +105,7 @@ function run_update(): void
        $items = Custom::list('SELECT * FROM old_item', [], new ArrayMapper());
        if (!$items->hasItems()) throw new DocumentException('Could not retrieve items');
        foreach ($items->items() as $item) {
-            Document::insert(Table::ITEM,
+            Document::insert(Table::Item,
                new Item($item['id'], $item['feed_id'], $item['title'], $item['item_guid'], $item['item_link'],
                    $item['published_on'], $item['updated_on'], $item['content'], $item['is_read'],
                    $item['is_bookmarked']));
--- a/src/util/refresh.php
+++ b/src/util/refresh.php
@ -1,5 +1,16 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * Feed Refresh Utility
+ *
+ * This will refresh all known feeds in the database; it is suitable for executing via cron or as a scheduled task
+ *
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */

+declare(strict_types=1);
+
+use BitBadger\InspiredByFSharp\Result;
 use BitBadger\PDODocument\{DocumentException, Find};
 use FeedReaderCentral\{Feed, Table, User};

@ -34,13 +45,16 @@ function refresh_all(): void
 {
    try {
        $users = [];
-        iterator_apply(Feed::retrieveAll()->items(), function (Feed $feed) use (&$users) {
+        Feed::retrieveAll()->iter(function (Feed $feed) use (&$users) {
            $result  = Feed::refreshFeed($feed->id, $feed->url);
            $userKey = "$feed->user_id";
-            if (!key_exists($userKey, $users)) $users[$userKey] = Find::byId(Table::USER, $feed->user_id, User::class);
-            if (array_key_exists('error', $result)) {
+            if (!key_exists($userKey, $users)) {
+                $users[$userKey] = Find::byId(Table::User, $feed->user_id, User::class)
+                    ->getOrDefault(new User(email: 'user-not-found'));
+            }
+            if ($result->isError()) {
                printfn('ERR (%s) %s', $users[$userKey]->email, $feed->url);
-                printfn('         %s', $result['error']);
+                printfn('         %s', $result->getError());
            } else {
                printfn('OK  (%s) %s', $users[$userKey]->email, $feed->url);
            }
--- a/src/util/search.php
+++ b/src/util/search.php
@ -1,4 +1,14 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * Search Maintenance Utility
+ *
+ * This allows on-demand refreshing of the search index (should be unnecessary in normal use)
+ *
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */
+
+declare(strict_types=1);

 use BitBadger\PDODocument\{Custom, DocumentException};
 use BitBadger\PDODocument\Mapper\ExistsMapper;
--- a/src/util/user.php
+++ b/src/util/user.php
@ -1,5 +1,17 @@
-<?php declare(strict_types=1);
+<?php
+/**
+ * User Maintenance Utility
+ *
+ * This provides several user maintenance functions for Feed Reader Central; none of these are available through the web
+ * interface
+ *
+ * @author Daniel J. Summers <daniel@bitbadger.solutions>
+ * @license MIT
+ */

+declare(strict_types=1);
+
+use BitBadger\InspiredByFSharp\Option;
 use BitBadger\PDODocument\{Count, Custom, Delete, DocumentException, Field, Parameters, Patch, Query};
 use FeedReaderCentral\{Security, Table, User};

@ -36,10 +48,10 @@ switch ($argv[1]) {
            printfn('Missing parameters: set-single-password requires a new password');
            exit(-1);
        }
-        set_password(Security::SINGLE_USER_EMAIL, $argv[2]);
+        set_password(Security::SingleUserEmail, $argv[2]);
        break;
    case 'reset-single-password':
-        set_password(Security::SINGLE_USER_EMAIL, Security::SINGLE_USER_PASSWORD);
+        set_password(Security::SingleUserEmail, Security::SingleUserPassword);
        break;
    case 'migrate-single-user':
        if ($argc < 4) {
@ -49,7 +61,7 @@ switch ($argv[1]) {
        migrate_single_user();
        break;
    case 'remove-single-user':
-        delete_user(Security::SINGLE_USER_EMAIL);
+        delete_user(Security::SingleUserEmail);
        break;
    default:
        printfn('Unrecognized option "%s"', $argv[1]);
@ -92,7 +104,7 @@ function add_user(): void
    try {
        // Ensure there is not already a user with this e-mail address
        $user = User::findByEmail($argv[2]);
-        if ($user) {
+        if ($user->isSome()) {
            printfn('A user with e-mail address "%s" already exists', $argv[2]);
            return;
        }
@ -113,7 +125,7 @@ function add_user(): void
 */
 function display_user(string $email): string
 {
-    return $email == Security::SINGLE_USER_EMAIL ? 'single-user mode user' : "user \"$email\"";
+    return $email === Security::SingleUserEmail ? 'single-user mode user' : "user \"$email\"";
 }

 /**
@ -126,14 +138,14 @@ function set_password(string $email, string $password): void

        // Ensure this user exists
        $user = User::findByEmail($email);
-        if (!$user) {
+        if ($user->isNone()) {
            printfn('No %s exists', $displayUser);
            return;
        }

        Security::updatePassword($email, $password);

-        $msg = $email == Security::SINGLE_USER_EMAIL && $password == Security::SINGLE_USER_PASSWORD
+        $msg = $email === Security::SingleUserEmail && $password === Security::SingleUserPassword
            ? 'reset' : sprintf('set to "%s"', $password);
        printfn('%s password %s successfully', init_cap($displayUser), $msg);
    } catch (DocumentException $ex) {
@ -152,14 +164,15 @@ function delete_user(string $email): void
        $displayUser = display_user($email);

        // Get the user for the provided e-mail address
-        $user = User::findByEmail($email);
-        if (!$user) {
+        $tryUser = User::findByEmail($email);
+        if ($tryUser->isNone()) {
            printfn('No %s exists', $displayUser);
            return;
        }

+        $user = $tryUser->get();
        try {
-            $feedCount = Count::byFields(Table::FEED, [Field::EQ('user_id', $user->id)]);
+            $feedCount = Count::byFields(Table::Feed, [Field::EQ('user_id', $user->id)]);
        } catch (DocumentException $ex) {
            printfn("$ex");
            return;
@ -172,12 +185,12 @@ function delete_user(string $email): void
        }

        try {
-            $fields = [Field::EQ('user_id', $user->id, '@user')];
+            $fields = [Field::EQ('user_id', $user->id, ':user')];
            Custom::nonQuery(
-                'DELETE FROM ' . Table::ITEM . " WHERE data->>'feed_id' IN (SELECT data->>'id' FROM " . Table::FEED
+                'DELETE FROM ' . Table::Item . " WHERE data->>'feed_id' IN (SELECT data->>'id' FROM " . Table::Feed
                    . ' WHERE ' . Query::whereByFields($fields) . ')', Parameters::addFields($fields, []));
-            Delete::byFields(Table::FEED, $fields);
-            Delete::byId(Table::USER, $user->id);
+            Delete::byFields(Table::Feed, $fields);
+            Delete::byId(Table::User, $user->id);

            printfn('%s deleted successfully', init_cap($displayUser));
        } catch (DocumentException $ex) {
@ -196,13 +209,14 @@ function migrate_single_user(): void
    global $argv;

    try {
-        if (!$single = User::findByEmail(Security::SINGLE_USER_EMAIL)) {
+        $single = User::findByEmail(Security::SingleUserEmail);
+        if ($single->isNone()) {
            printfn('There is no single-user mode user to be migrated');
            return;
        }

-        Patch::byId(Table::USER, $single->id,
-            ['email' => $argv[2], 'password' => password_hash($argv[3], Security::PW_ALGORITHM)]);
+        Patch::byId(Table::User, $single->get()->id,
+            ['email' => $argv[2], 'password' => password_hash($argv[3], Security::PasswordAlgorithm)]);

        printfn('The single user has been moved to "%s", with password "%s"', $argv[2], $argv[3]);
    } catch (DocumentException $ex) {