Correctly deal with JsonNull (#84)

ConsumePlugin/GeneratedRestClient.fs

@@ -211,6 +211,72 @@ module PureGymApi =
                 }
                 |> (fun a -> Async.StartAsTask (a, ?cancellationToken = ct))
 
+            member _.PostStringToString (foo : Map<string, string> option, ct : CancellationToken option) =
+                async {
+                    let! ct = Async.CancellationToken
+
+                    let uri =
+                        System.Uri (
+                            (match client.BaseAddress with
+                             | null -> System.Uri "https://whatnot.com"
+                             | v -> v),
+                            System.Uri ("some/url", System.UriKind.Relative)
+                        )
+
+                    let httpMessage =
+                        new System.Net.Http.HttpRequestMessage (
+                            Method = System.Net.Http.HttpMethod.Post,
+                            RequestUri = uri
+                        )
+
+                    let queryParams =
+                        new System.Net.Http.StringContent (
+                            foo
+                            |> (fun field ->
+                                match field with
+                                | None -> null :> System.Text.Json.Nodes.JsonNode
+                                | Some field ->
+                                    ((fun field ->
+                                        let ret = System.Text.Json.Nodes.JsonObject ()
+
+                                        for (KeyValue (key, value)) in field do
+                                            ret.Add (
+                                                key.ToString (),
+                                                System.Text.Json.Nodes.JsonValue.Create<string> value
+                                            )
+
+                                        ret
+                                    )
+                                        field)
+                                    :> System.Text.Json.Nodes.JsonNode
+                            )
+                            |> (fun node -> if isNull node then "null" else node.ToJsonString ())
+                        )
+
+                    do httpMessage.Content <- queryParams
+                    let! response = client.SendAsync (httpMessage, ct) |> Async.AwaitTask
+                    let response = response.EnsureSuccessStatusCode ()
+                    let! responseStream = response.Content.ReadAsStreamAsync ct |> Async.AwaitTask
+
+                    let! jsonNode =
+                        System.Text.Json.Nodes.JsonNode.ParseAsync (responseStream, cancellationToken = ct)
+                        |> Async.AwaitTask
+
+                    return
+                        match jsonNode with
+                        | null -> None
+                        | v ->
+                            v.AsObject ()
+                            |> Seq.map (fun kvp ->
+                                let key = (kvp.Key)
+                                let value = (kvp.Value).AsValue().GetValue<string> ()
+                                key, value
+                            )
+                            |> Map.ofSeq
+                            |> Some
+                }
+                |> (fun a -> Async.StartAsTask (a, ?cancellationToken = ct))
+
             member _.GetSessions (fromDate : DateOnly, toDate : DateOnly, ct : CancellationToken option) =
                 async {
                     let! ct = Async.CancellationToken
@@ -403,7 +469,9 @@ module PureGymApi =
 
                     let queryParams =
                         new System.Net.Http.StringContent (
-                            user |> PureGym.Member.toJsonNode |> (fun node -> node.ToJsonString ())
+                            user
+                            |> PureGym.Member.toJsonNode
+                            |> (fun node -> if isNull node then "null" else node.ToJsonString ())
                         )
 
                     do httpMessage.Content <- queryParams
@@ -436,7 +504,7 @@ module PureGymApi =
                         new System.Net.Http.StringContent (
                             user
                             |> System.Text.Json.Nodes.JsonValue.Create<Uri>
-                            |> (fun node -> node.ToJsonString ())
+                            |> (fun node -> if isNull node then "null" else node.ToJsonString ())
                         )
 
                     do httpMessage.Content <- queryParams
@@ -469,7 +537,7 @@ module PureGymApi =
                         new System.Net.Http.StringContent (
                             user
                             |> System.Text.Json.Nodes.JsonValue.Create<int>
-                            |> (fun node -> node.ToJsonString ())
+                            |> (fun node -> if isNull node then "null" else node.ToJsonString ())
                         )
 
                     do httpMessage.Content <- queryParams

ConsumePlugin/RestApiExample.fs

@@ -29,6 +29,10 @@ type IPureGymApi =
     [<Get "some/url">]
     abstract GetUrl : ?ct : CancellationToken -> Task<UriThing>
 
+    [<Post "some/url">]
+    abstract PostStringToString :
+        [<Body>] foo : Map<string, string> option * ?ct : CancellationToken -> Task<Map<string, string> option>
+
     // We'll use this one to check handling of absolute URIs too
     [<Get "/v2/gymSessions/member">]
     abstract GetSessions :

WoofWare.Myriad.Plugins.Test/TestHttpClient/TestPureGymRestApi.fs

@@ -257,3 +257,37 @@ module TestPureGymRestApi =
         uri.ToString () |> shouldEqual "https://patrick@en.wikipedia.org/wiki/foo"
         uri.UserInfo |> shouldEqual "patrick"
         uri.Host |> shouldEqual "en.wikipedia.org"
+
+    [<TestCase false>]
+    [<TestCase true>]
+    let ``Map<string, string> option example`` (isSome : bool) =
+        let proc (message : HttpRequestMessage) : HttpResponseMessage Async =
+            async {
+                message.Method |> shouldEqual HttpMethod.Post
+
+                message.RequestUri.ToString () |> shouldEqual "https://whatnot.com/some/url"
+                let! content = message.Content.ReadAsStringAsync () |> Async.AwaitTask
+
+                if isSome then
+                    content |> shouldEqual """{"hi":"bye"}"""
+                else
+                    content |> shouldEqual "null"
+
+                let content = new StringContent (content)
+
+                let resp = new HttpResponseMessage (HttpStatusCode.OK)
+                resp.Content <- content
+                return resp
+            }
+
+        use client = HttpClientMock.makeNoUri proc
+        let api = PureGymApi.make client
+
+        let expected =
+            if isSome then
+                [ "hi", "bye" ] |> Map.ofList |> Some
+            else
+                None
+
+        let actual = api.PostStringToString(expected).Result
+        actual |> shouldEqual expected

WoofWare.Myriad.Plugins.Test/TestJsonSerialize/TestJsonSerde.fs

@@ -2,6 +2,9 @@ namespace WoofWare.Myriad.Plugins.Test
 
 open System
 open System.Collections.Generic
+open System.IO
+open System.Text
+open System.Text.Json
 open System.Text.Json.Nodes
 open NUnit.Framework
 open FsCheck

WoofWare.Myriad.Plugins/HttpClientGenerator.fs

@@ -516,12 +516,18 @@ module internal HttpClientGenerator =
                                     |> SynExpr.pipeThroughFunction (
                                         SynExpr.createLambda
                                             "node"
+                                            (SynExpr.ifThenElse
+                                                (SynExpr.CreateApp (
+                                                    SynExpr.CreateIdentString "isNull",
+                                                    SynExpr.CreateIdentString "node"
+                                                ))
                                                 (SynExpr.CreateApp (
                                                     SynExpr.CreateLongIdent (
                                                         SynLongIdent.Create [ "node" ; "ToJsonString" ]
                                                     ),
                                                     SynExpr.CreateConst SynConst.Unit
                                                 ))
+                                                (SynExpr.CreateConst (SynConst.CreateString "null")))
                                     )
                                 ),
                                 range0

WoofWare.Myriad.Plugins/JsonSerializeGenerator.fs

@@ -65,11 +65,14 @@ module internal JsonSerializeGenerator =
                     SynMatchClause.Create (
                         SynPat.CreateLongIdent (SynLongIdent.CreateString "None", []),
                         None,
-                        SynExpr.CreateApp (
+                        // The absolutely galaxy-brained implementation of JsonValue has `JsonValue.Parse "null"`
-                            SynExpr.CreateLongIdent (
+                        // identically equal to null. We have to work around this later, but we might as well just
-                                SynLongIdent.Create [ "System" ; "Text" ; "Json" ; "Nodes" ; "JsonValue" ; "Create" ]
+                        // be efficient here and whip up the null directly.
-                            ),
                         SynExpr.CreateNull
+                        |> SynExpr.upcast' (
+                            SynType.CreateLongIdent (
+                                SynLongIdent.Create [ "System" ; "Text" ; "Json" ; "Nodes" ; "JsonNode" ]
+                            )
                         )
                     )
 
@@ -80,6 +83,12 @@ module internal JsonSerializeGenerator =
                         ),
                         None,
                         SynExpr.CreateApp (serializeNode ty, SynExpr.CreateIdentString "field")
+                        |> SynExpr.CreateParen
+                        |> SynExpr.upcast' (
+                            SynType.CreateLongIdent (
+                                SynLongIdent.Create [ "System" ; "Text" ; "Json" ; "Nodes" ; "JsonNode" ]
+                            )
+                        )
                     )
                 ]
             )

WoofWare.Myriad.Plugins/SynExpr.fs

@@ -263,6 +263,8 @@ module internal SynExpr =
             |> callMethodArg "ToString" (SynExpr.CreateConstString "yyyy-MM-ddTHH:mm:ss")
         | _ -> callMethod "ToString" ident
 
+    let upcast' (ty : SynType) (e : SynExpr) = SynExpr.Upcast (e, ty, range0)
+
     let synBindingTriviaZero (isMember : bool) =
         {
             SynBindingTrivia.EqualsRange = Some range0