Make Json calls and stream writes async

src/Postgres/Library.fs

@@ -326,13 +326,14 @@ module Results =
     /// <param name="sqlProps">The query from which JSON should be extracted</param>
     /// <returns>A JSON array as a string; no results will produce an empty array (<c>"[]"</c>)</returns>
     [<CompiledName "FSharpToJsonArray">]
-    let toJsonArray (mapFunc: RowReader -> string) sqlProps =
+    let toJsonArray (mapFunc: RowReader -> string) sqlProps = backgroundTask {
         let output = StringBuilder("[")
-        sqlProps
-        |> Sql.iter (fun it ->
-            if output.Length > 2 then ignore (output.Append ",")
-            mapFunc it |> output.Append |> ignore)
-        output.Append("]").ToString()
+        do! sqlProps
+            |> Sql.iterAsync (fun it ->
+                if output.Length > 2 then ignore (output.Append ",")
+                mapFunc it |> output.Append |> ignore)
+        return output.Append("]").ToString()
+    }
 
     /// <summary>Create a JSON array of items for the results of a query</summary>
     /// <param name="mapFunc">The mapping function to extract JSON from the query's results</param>
@@ -346,14 +347,15 @@ module Results =
     /// <param name="mapFunc">The mapping function to extract JSON from the query's results</param>
     /// <param name="sqlProps">The query from which JSON should be extracted</param>
     [<CompiledName "FSharpWriteJsonArray">]
-    let writeJsonArray (writer: StreamWriter) (mapFunc: RowReader -> string) sqlProps =
-        writer.Write "["
+    let writeJsonArray (writer: StreamWriter) (mapFunc: RowReader -> string) sqlProps = backgroundTask {
+        do! writer.WriteAsync "["
         let mutable isFirst = true
-        sqlProps
-        |> Sql.iter (fun it ->
-            if isFirst then isFirst <- false else writer.Write ","
-            mapFunc it |> writer.Write)
-        writer.Write "]"
+        do! sqlProps
+            |> Sql.iterAsync (fun it ->
+                if isFirst then isFirst <- false else writer.Write ","
+                writer.WriteAsync(mapFunc it).ConfigureAwait(false).GetAwaiter().GetResult())
+        do! writer.WriteAsync "]"
+    }
 
     /// <summary>Write a JSON array of items for the results of a query to the given <c>StreamWriter</c></summary>
     /// <param name="writer">The StreamWriter to which results should be written</param>

src/Postgres/WithProps.fs

@@ -107,9 +107,10 @@ module Custom =
     /// <param name="sqlProps">The <c>SqlProps</c> to use to execute the query</param>
     /// <returns>The JSON document with the first matching result, or an empty document if not found</returns>
     [<CompiledName "FSharpJsonSingle">]
-    let jsonSingle query parameters mapFunc sqlProps =
-        let results = jsonArray $"%s{query} LIMIT 1" parameters mapFunc sqlProps
-        if results = "[]" then "{}" else results[1..results.Length - 2]
+    let jsonSingle query parameters mapFunc sqlProps = backgroundTask {
+        let! results = jsonArray $"%s{query} LIMIT 1" parameters mapFunc sqlProps
+        return if results = "[]" then "{}" else results[1..results.Length - 2]
+    }
 
     /// <summary>Execute a query that returns one or no JSON documents</summary>
     /// <param name="query">The query to retrieve the results</param>
@@ -972,8 +973,10 @@ module Json =
     /// <param name="fields">The field conditions to match</param>
     /// <param name="sqlProps">The <c>SqlProps</c> to use to execute the query</param>
     [<CompiledName "WriteFirstByFields">]
-    let writeFirstByFields tableName (writer: StreamWriter) howMatched fields sqlProps =
-        firstByFields tableName howMatched fields sqlProps |> writer.Write
+    let writeFirstByFields tableName (writer: StreamWriter) howMatched fields sqlProps = backgroundTask {
+        let! json = firstByFields tableName howMatched fields sqlProps
+        do! writer.WriteAsync json
+    }
 
     /// <summary>
     /// Retrieve the first JSON document matching JSON field comparisons (<c>-&gt;&gt; =</c>, etc.) ordered by the given
@@ -1005,7 +1008,10 @@ module Json =
     /// <param name="sqlProps">The <c>SqlProps</c> to use to execute the query</param>
     [<CompiledName "WriteFirstByFieldsOrdered">]
     let writeFirstByFieldsOrdered tableName (writer: StreamWriter) howMatched queryFields orderFields sqlProps =
-        firstByFieldsOrdered tableName howMatched queryFields orderFields sqlProps |> writer.Write
+        backgroundTask {
+            let! json = firstByFieldsOrdered tableName howMatched queryFields orderFields sqlProps
+            do! writer.WriteAsync json
+        }
 
     /// <summary>Retrieve the first JSON document matching a JSON containment query (<c>@&gt;</c>)</summary>
     /// <param name="tableName">The table from which a document should be retrieved (may include schema)</param>
@@ -1025,8 +1031,10 @@ module Json =
     /// <param name="criteria">The document to match with the containment query</param>
     /// <param name="sqlProps">The <c>SqlProps</c> to use to execute the query</param>
     [<CompiledName "WriteFirstByContains">]
-    let writeFirstByContains tableName (writer: StreamWriter) (criteria: obj) sqlProps =
-        firstByContains tableName criteria sqlProps |> writer.Write
+    let writeFirstByContains tableName (writer: StreamWriter) (criteria: obj) sqlProps = backgroundTask {
+        let! json = firstByContains tableName criteria sqlProps
+        do! writer.WriteAsync json
+    }
 
     /// <summary>
     /// Retrieve the first JSON document matching a JSON containment query (<c>@&gt;</c>) ordered by the given fields in
@@ -1056,7 +1064,10 @@ module Json =
     /// <param name="sqlProps">The <c>SqlProps</c> to use to execute the query</param>
     [<CompiledName "WriteFirstByContainsOrdered">]
     let writeFirstByContainsOrdered tableName (writer: StreamWriter) (criteria: obj) orderFields sqlProps =
-        firstByContainsOrdered tableName criteria orderFields sqlProps |> writer.Write
+        backgroundTask {
+            let! json = firstByContainsOrdered tableName criteria orderFields sqlProps
+            do! writer.WriteAsync json
+        }
 
     /// <summary>Retrieve the first JSON document matching a JSON Path match query (<c>@?</c>)</summary>
     /// <param name="tableName">The table from which a document should be retrieved (may include schema)</param>
@@ -1076,8 +1087,10 @@ module Json =
     /// <param name="jsonPath">The JSON Path expression to match</param>
     /// <param name="sqlProps">The <c>SqlProps</c> to use to execute the query</param>
     [<CompiledName "WriteFirstByJsonPath">]
-    let writeFirstByJsonPath tableName (writer: StreamWriter) jsonPath sqlProps =
-        firstByJsonPath tableName jsonPath sqlProps |> writer.Write
+    let writeFirstByJsonPath tableName (writer: StreamWriter) jsonPath sqlProps = backgroundTask {
+        let! json = firstByJsonPath tableName jsonPath sqlProps
+        do! writer.WriteAsync json
+    }
 
     /// <summary>
     /// Retrieve the first JSON document matching a JSON Path match query (<c>@?</c>) ordered by the given fields in the
@@ -1106,8 +1119,10 @@ module Json =
     /// <param name="orderFields">Fields by which the results should be ordered</param>
     /// <param name="sqlProps">The <c>SqlProps</c> to use to execute the query</param>
     [<CompiledName "WriteFirstByJsonPathOrdered">]
-    let writeFirstByJsonPathOrdered tableName (writer: StreamWriter) jsonPath orderFields sqlProps =
-        firstByJsonPathOrdered tableName jsonPath orderFields sqlProps |> writer.Write
+    let writeFirstByJsonPathOrdered tableName (writer: StreamWriter) jsonPath orderFields sqlProps = backgroundTask {
+        let! json = firstByJsonPathOrdered tableName jsonPath orderFields sqlProps
+        do! writer.WriteAsync json
+    }
 
 /// <summary>Commands to update documents</summary>
 [<RequireQualifiedAccess>]