myWebLog/src/MyWebLog/DotLiquidBespoke.fs

239 lines
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/// Custom DotLiquid filters and tags
module MyWebLog.DotLiquidBespoke
open System
open System.IO
open System.Web
open DotLiquid
open Giraffe.ViewEngine
open MyWebLog.ViewModels
/// Get the current web log from the DotLiquid context
let webLog (ctx : Context) =
ctx.Environments[0].["web_log"] :?> WebLog
/// Does an asset exist for the current theme?
let assetExists fileName (webLog : WebLog) =
ThemeAssetCache.get (ThemeId webLog.themePath) |> List.exists (fun it -> it = fileName)
/// Obtain the link from known types
let permalink (ctx : Context) (item : obj) (linkFunc : WebLog -> Permalink -> string) =
match item with
| :? String as link -> Some link
| :? DisplayPage as page -> Some page.permalink
| :? PostListItem as post -> Some post.permalink
| :? DropProxy as proxy -> Option.ofObj proxy["permalink"] |> Option.map string
| _ -> None
|> function
| Some link -> linkFunc (webLog ctx) (Permalink link)
| None -> $"alert('unknown item type {item.GetType().Name}')"
/// A filter to generate an absolute link
type AbsoluteLinkFilter () =
static member AbsoluteLink (ctx : Context, item : obj) =
permalink ctx item WebLog.absoluteUrl
/// A filter to generate a link with posts categorized under the given category
type CategoryLinkFilter () =
static member CategoryLink (ctx : Context, catObj : obj) =
match catObj with
| :? DisplayCategory as cat -> Some cat.slug
| :? DropProxy as proxy -> Option.ofObj proxy["slug"] |> Option.map string
| _ -> None
|> function
| Some slug -> WebLog.relativeUrl (webLog ctx) (Permalink $"category/{slug}/")
| None -> $"alert('unknown category object type {catObj.GetType().Name}')"
/// A filter to generate a link that will edit a page
type EditPageLinkFilter () =
static member EditPageLink (ctx : Context, pageObj : obj) =
match pageObj with
| :? DisplayPage as page -> Some page.id
| :? DropProxy as proxy -> Option.ofObj proxy["id"] |> Option.map string
| :? String as theId -> Some theId
| _ -> None
|> function
| Some pageId -> WebLog.relativeUrl (webLog ctx) (Permalink $"admin/page/{pageId}/edit")
| None -> $"alert('unknown page object type {pageObj.GetType().Name}')"
/// A filter to generate a link that will edit a post
type EditPostLinkFilter () =
static member EditPostLink (ctx : Context, postObj : obj) =
match postObj with
| :? PostListItem as post -> Some post.id
| :? DropProxy as proxy -> Option.ofObj proxy["id"] |> Option.map string
| :? String as theId -> Some theId
| _ -> None
|> function
| Some postId -> WebLog.relativeUrl (webLog ctx) (Permalink $"admin/post/{postId}/edit")
| None -> $"alert('unknown post object type {postObj.GetType().Name}')"
/// A filter to generate nav links, highlighting the active link (exact match)
type NavLinkFilter () =
static member NavLink (ctx : Context, url : string, text : string) =
let webLog = webLog ctx
let _, path = WebLog.hostAndPath webLog
let path = if path = "" then path else $"{path.Substring 1}/"
seq {
"<li class=\"nav-item\"><a class=\"nav-link"
if (string ctx.Environments[0].["current_page"]).StartsWith $"{path}{url}" then " active"
"\" href=\""
WebLog.relativeUrl webLog (Permalink url)
"\">"
text
"</a></li>"
}
|> Seq.fold (+) ""
/// A filter to generate a link for theme asset (image, stylesheet, script, etc.)
type ThemeAssetFilter () =
static member ThemeAsset (ctx : Context, asset : string) =
let webLog = webLog ctx
WebLog.relativeUrl webLog (Permalink $"themes/{webLog.themePath}/{asset}")
/// Create various items in the page header based on the state of the page being generated
type PageHeadTag () =
inherit Tag ()
override this.Render (context : Context, result : TextWriter) =
let webLog = webLog context
// spacer
let s = " "
let getBool name =
context.Environments[0].[name] |> Option.ofObj |> Option.map Convert.ToBoolean |> Option.defaultValue false
result.WriteLine $"""<meta name="generator" content="{context.Environments[0].["generator"]}">"""
// Theme assets
if assetExists "style.css" webLog then
result.WriteLine $"""{s}<link rel="stylesheet" href="{ThemeAssetFilter.ThemeAsset (context, "style.css")}">"""
if assetExists "favicon.ico" webLog then
result.WriteLine $"""{s}<link rel="icon" href="{ThemeAssetFilter.ThemeAsset (context, "favicon.ico")}">"""
// RSS feeds and canonical URLs
let feedLink title url =
let escTitle = HttpUtility.HtmlAttributeEncode title
let relUrl = WebLog.relativeUrl webLog (Permalink url)
$"""{s}<link rel="alternate" type="application/rss+xml" title="{escTitle}" href="{relUrl}">"""
if webLog.rss.feedEnabled && getBool "is_home" then
result.WriteLine (feedLink webLog.name webLog.rss.feedName)
result.WriteLine $"""{s}<link rel="canonical" href="{WebLog.absoluteUrl webLog Permalink.empty}">"""
if webLog.rss.categoryEnabled && getBool "is_category_home" then
let slug = context.Environments[0].["slug"] :?> string
result.WriteLine (feedLink webLog.name $"category/{slug}/{webLog.rss.feedName}")
if webLog.rss.tagEnabled && getBool "is_tag_home" then
let slug = context.Environments[0].["slug"] :?> string
result.WriteLine (feedLink webLog.name $"tag/{slug}/{webLog.rss.feedName}")
if getBool "is_post" then
let post = context.Environments[0].["model"] :?> PostDisplay
let url = WebLog.absoluteUrl webLog (Permalink post.posts[0].permalink)
result.WriteLine $"""{s}<link rel="canonical" href="{url}">"""
if getBool "is_page" then
let page = context.Environments[0].["page"] :?> DisplayPage
let url = WebLog.absoluteUrl webLog (Permalink page.permalink)
result.WriteLine $"""{s}<link rel="canonical" href="{url}">"""
/// Create various items in the page header based on the state of the page being generated
type PageFootTag () =
inherit Tag ()
override this.Render (context : Context, result : TextWriter) =
let webLog = webLog context
// spacer
let s = " "
if webLog.autoHtmx then
result.WriteLine $"{s}{RenderView.AsString.htmlNode Htmx.Script.minified}"
if assetExists "script.js" webLog then
result.WriteLine $"""{s}<script src="{ThemeAssetFilter.ThemeAsset (context, "script.js")}"></script>"""
/// A filter to generate a relative link
type RelativeLinkFilter () =
static member RelativeLink (ctx : Context, item : obj) =
permalink ctx item WebLog.relativeUrl
/// A filter to generate a link with posts tagged with the given tag
type TagLinkFilter () =
static member TagLink (ctx : Context, tag : string) =
ctx.Environments[0].["tag_mappings"] :?> TagMap list
|> List.tryFind (fun it -> it.tag = tag)
|> function
| Some tagMap -> tagMap.urlValue
| None -> tag.Replace (" ", "+")
|> function tagUrl -> WebLog.relativeUrl (webLog ctx) (Permalink $"tag/{tagUrl}/")
/// Create links for a user to log on or off, and a dashboard link if they are logged off
type UserLinksTag () =
inherit Tag ()
override this.Render (context : Context, result : TextWriter) =
let webLog = webLog context
let link it = WebLog.relativeUrl webLog (Permalink it)
seq {
"""<ul class="navbar-nav flex-grow-1 justify-content-end">"""
match Convert.ToBoolean context.Environments[0].["logged_on"] with
| true ->
$"""<li class="nav-item"><a class="nav-link" href="{link "admin/dashboard"}">Dashboard</a></li>"""
$"""<li class="nav-item"><a class="nav-link" href="{link "user/log-off"}">Log Off</a></li>"""
| false ->
$"""<li class="nav-item"><a class="nav-link" href="{link "user/log-on"}">Log On</a></li>"""
"</ul>"
}
|> Seq.iter result.WriteLine
/// A filter to retrieve the value of a meta item from a list
// (shorter than `{% assign item = list | where: "name", [name] | first %}{{ item.value }}`)
type ValueFilter () =
static member Value (_ : Context, items : MetaItem list, name : string) =
match items |> List.tryFind (fun it -> it.name = name) with
| Some item -> item.value
| None -> $"-- {name} not found --"
open System.Collections.Generic
open Microsoft.AspNetCore.Antiforgery
/// Register custom filters/tags and safe types
let register () =
[ typeof<AbsoluteLinkFilter>; typeof<CategoryLinkFilter>; typeof<EditPageLinkFilter>; typeof<EditPostLinkFilter>
typeof<NavLinkFilter>; typeof<RelativeLinkFilter>; typeof<TagLinkFilter>; typeof<ThemeAssetFilter>
typeof<ValueFilter>
]
|> List.iter Template.RegisterFilter
Template.RegisterTag<PageHeadTag> "page_head"
Template.RegisterTag<PageFootTag> "page_foot"
Template.RegisterTag<UserLinksTag> "user_links"
[ // Domain types
typeof<CustomFeed>; typeof<Episode>; typeof<Episode option>; typeof<MetaItem>; typeof<Page>
typeof<RssOptions>; typeof<TagMap>; typeof<UploadDestination>; typeof<WebLog>
// View models
typeof<DashboardModel>; typeof<DisplayCategory>; typeof<DisplayCustomFeed>; typeof<DisplayPage>
typeof<DisplayUpload>; typeof<EditCategoryModel>; typeof<EditCustomFeedModel>; typeof<EditPageModel>
typeof<EditPostModel>; typeof<EditRssModel>; typeof<EditTagMapModel>; typeof<EditUserModel>
typeof<LogOnModel>; typeof<ManagePermalinksModel>; typeof<PostDisplay>; typeof<PostListItem>
typeof<SettingsModel>; typeof<UserMessage>
// Framework types
typeof<AntiforgeryTokenSet>; typeof<DateTime option>; typeof<int option>; typeof<KeyValuePair>
typeof<MetaItem list>; typeof<string list>; typeof<string option>; typeof<TagMap list>
]
|> List.iter (fun it -> Template.RegisterSafeType (it, [| "*" |]))