Delete user / admin clean-up (#19)

- Add CLI help (#22)
- Add constants for common view items
- Construct hashes with piped functions

src/MyWebLog.Data/Interfaces.fs

@@ -255,6 +255,9 @@ type IWebLogUserData =
     /// Add a web log user
     abstract member Add : WebLogUser -> Task<unit>
     
+    /// Delete a web log user
+    abstract member Delete : WebLogUserId -> WebLogId -> Task<Result<bool, string>>
+    
     /// Find a web log user by their e-mail address
     abstract member FindByEmail : email : string -> WebLogId -> Task<WebLogUser option>
     

src/MyWebLog.Data/RethinkDbData.fs

@@ -955,6 +955,44 @@ type RethinkDbData (conn : Net.IConnection, config : DataConfig, log : ILogger<R
                     write; withRetryDefault; ignoreResult conn
                 }
                 
+                member _.FindById userId webLogId =
+                    rethink<WebLogUser> {
+                        withTable Table.WebLogUser
+                        get userId
+                        resultOption; withRetryOptionDefault
+                    }
+                    |> verifyWebLog webLogId (fun u -> u.WebLogId) <| conn
+                
+                member this.Delete userId webLogId = backgroundTask {
+                    match! this.FindById userId webLogId with
+                    | Some _ ->
+                        let! pageCount = rethink<int> {
+                            withTable Table.Page
+                            getAll [ webLogId ] (nameof Page.empty.WebLogId)
+                            filter (nameof Page.empty.AuthorId) userId
+                            count
+                            result; withRetryDefault conn
+                        }
+                        let! postCount = rethink<int> {
+                            withTable Table.Post
+                            getAll [ webLogId ] (nameof Post.empty.WebLogId)
+                            filter (nameof Post.empty.AuthorId) userId
+                            count
+                            result; withRetryDefault conn
+                        }
+                        if pageCount + postCount > 0 then
+                            return Result.Error "User has pages or posts; cannot delete"
+                        else
+                            do! rethink {
+                                withTable Table.WebLogUser
+                                get userId
+                                delete
+                                write; withRetryDefault; ignoreResult conn
+                            }
+                            return Ok true
+                    | None -> return Result.Error "User does not exist"
+                }
+                
                 member _.FindByEmail email webLogId =
                     rethink<WebLogUser list> {
                         withTable Table.WebLogUser
@@ -964,17 +1002,10 @@ type RethinkDbData (conn : Net.IConnection, config : DataConfig, log : ILogger<R
                     }
                     |> tryFirst <| conn
                 
-                member _.FindById userId webLogId =
-                    rethink<WebLogUser> {
-                        withTable Table.WebLogUser
-                        get userId
-                        resultOption; withRetryOptionDefault
-                    }
-                    |> verifyWebLog webLogId (fun u -> u.WebLogId) <| conn
-                
                 member _.FindByWebLog webLogId = rethink<WebLogUser list> {
                     withTable Table.WebLogUser
                     getAll [ webLogId ] (nameof WebLogUser.empty.WebLogId)
+                    orderByFunc (fun row -> row[nameof WebLogUser.empty.PreferredName].Downcase ())
                     result; withRetryDefault conn
                 }
                 

src/MyWebLog.Data/SQLite/SQLiteWebLogUserData.fs

@@ -43,6 +43,34 @@ type SQLiteWebLogUserData (conn : SqliteConnection) =
         do! write cmd
     }
     
+    /// Find a user by their ID for the given web log
+    let findById userId webLogId = backgroundTask {
+        use cmd = conn.CreateCommand ()
+        cmd.CommandText <- "SELECT * FROM web_log_user WHERE id = @id"
+        cmd.Parameters.AddWithValue ("@id", WebLogUserId.toString userId) |> ignore
+        use! rdr = cmd.ExecuteReaderAsync ()
+        return Helpers.verifyWebLog<WebLogUser> webLogId (fun u -> u.WebLogId) Map.toWebLogUser rdr 
+    }
+    
+    /// Delete a user if they have no posts or pages
+    let delete userId webLogId = backgroundTask {
+        match! findById userId webLogId with
+        | Some _ ->
+            use cmd = conn.CreateCommand ()
+            cmd.CommandText <- "SELECT COUNT(id) FROM page WHERE author_id = @userId"
+            cmd.Parameters.AddWithValue ("@userId", WebLogUserId.toString userId) |> ignore
+            let! pageCount = count cmd
+            cmd.CommandText <- "SELECT COUNT(id) FROM post WHERE author_id = @userId"
+            let! postCount = count cmd
+            if pageCount + postCount > 0 then
+                return Error "User has pages or posts; cannot delete"
+            else
+                cmd.CommandText <- "DELETE FROM web_log_user WHERE id = @userId"
+                let! _ = cmd.ExecuteNonQueryAsync ()
+                return Ok true
+        | None -> return Error "User does not exist"
+    }
+    
     /// Find a user by their e-mail address for the given web log
     let findByEmail (email : string) webLogId = backgroundTask {
         use cmd = conn.CreateCommand ()
@@ -53,19 +81,10 @@ type SQLiteWebLogUserData (conn : SqliteConnection) =
         return if rdr.Read () then Some (Map.toWebLogUser rdr) else None
     }
     
-    /// Find a user by their ID for the given web log
-    let findById userId webLogId = backgroundTask {
-        use cmd = conn.CreateCommand ()
-        cmd.CommandText <- "SELECT * FROM web_log_user WHERE id = @id"
-        cmd.Parameters.AddWithValue ("@id", WebLogUserId.toString userId) |> ignore
-        use! rdr = cmd.ExecuteReaderAsync ()
-        return Helpers.verifyWebLog<WebLogUser> webLogId (fun u -> u.WebLogId) Map.toWebLogUser rdr 
-    }
-    
     /// Get all users for the given web log
     let findByWebLog webLogId = backgroundTask {
         use cmd = conn.CreateCommand ()
-        cmd.CommandText <- "SELECT * FROM web_log_user WHERE web_log_id = @webLogId"
+        cmd.CommandText <- "SELECT * FROM web_log_user WHERE web_log_id = @webLogId ORDER BY LOWER(preferred_name)"
         addWebLogId cmd webLogId
         use! rdr = cmd.ExecuteReaderAsync ()
         return toList Map.toWebLogUser rdr
@@ -133,6 +152,7 @@ type SQLiteWebLogUserData (conn : SqliteConnection) =
     
     interface IWebLogUserData with
         member _.Add user = add user
+        member _.Delete userId webLogId = delete userId webLogId
         member _.FindByEmail email webLogId = findByEmail email webLogId
         member _.FindById userId webLogId = findById userId webLogId
         member _.FindByWebLog webLogId = findByWebLog webLogId