Replace Newtonsoft.Json with System.Text.Json (byte-equal wire format)

Fable.Remoting.AspNetCore/Middleware.fs

@@ -48,11 +48,11 @@ module internal Middleware =
 
     let (>=>) = compose
 
-    let setResponseBody (response: obj) logger : HttpHandler =
+    let setResponseBody (backend: JsonSerializerBackend) (response: obj) logger : HttpHandler =
         fun (next : HttpFunc) (ctx : HttpContext) ->
             task {
                 use ms = new MemoryStream ()
-                jsonSerialize response ms
+                jsonSerializeWithBackend backend response ms
                 let responseBody = System.Text.Encoding.UTF8.GetString (ms.ToArray ())
                 return! writeStringAsync responseBody ctx logger
             }
@@ -66,8 +66,8 @@ module internal Middleware =
             }
 
     /// Sets the body of the response to type of JSON
-    let setBody value logger : HttpHandler =
-        setResponseBody value logger
+    let setBody backend value logger : HttpHandler =
+        setResponseBody backend value logger
         >=> setContentType "application/json; charset=utf-8"
 
     /// Used to forward of the Http context
@@ -76,14 +76,15 @@ module internal Middleware =
 
     let fail (ex: exn) (routeInfo: RouteInfo<HttpContext>) (options: RemotingOptions<HttpContext, 't>) : HttpHandler =
       let logger = options.DiagnosticsLogger
+      let backend = options.JsonSerializer
       fun (next : HttpFunc) (ctx : HttpContext) ->
         task {
             match options.ErrorHandler with
-            | None -> return! setBody (Errors.unhandled routeInfo.methodName) logger next ctx
+            | None -> return! setBody backend (Errors.unhandled routeInfo.methodName) logger next ctx
             | Some errorHandler ->
                 match errorHandler ex routeInfo with
-                | Ignore -> return! setBody (Errors.ignored routeInfo.methodName) logger next ctx
-                | Propagate error -> return! setBody (Errors.propagated error) logger next ctx
+                | Ignore -> return! setBody backend (Errors.ignored routeInfo.methodName) logger next ctx
+                | Propagate error -> return! setBody backend (Errors.propagated error) logger next ctx
         }
 
     let notFound (options: RemotingOptions<HttpContext, 'impl>) next (ctx: HttpContext) =

Fable.Remoting.AwsLambda/FableLambdaAdapter.fs

@@ -34,14 +34,15 @@ module private FuncsUtil =
   let private path (r: HttpRequestData) = r.RawPath
 
   let setJsonBody
+    (backend: JsonSerializerBackend)
     (res: HttpResponseData)
     (response: obj)
     (logger: Option<string -> unit>)
     (req: HttpRequestData)
     : Task<HttpResponseData option> =
     task {
       use ms = new MemoryStream()
-      jsonSerialize response ms
+      jsonSerializeWithBackend backend response ms
       let responseBody = System.Text.Encoding.UTF8.GetString(ms.ToArray())
       Diagnostics.outputPhase logger responseBody
       res.SetHeaderValues("Content-Type", "application/json; charset=utf-8", false)
@@ -58,13 +59,14 @@ module private FuncsUtil =
     : Task<HttpResponseData option> =
     let resp = HttpResponseData(StatusCode = int HttpStatusCode.InternalServerError)
     let logger = options.DiagnosticsLogger
+    let backend = options.JsonSerializer
 
     match options.ErrorHandler with
-    | None -> setJsonBody resp (Errors.unhandled routeInfo.methodName) logger req
+    | None -> setJsonBody backend resp (Errors.unhandled routeInfo.methodName) logger req
     | Some errorHandler ->
       match errorHandler ex routeInfo with
-      | Ignore -> setJsonBody resp (Errors.ignored routeInfo.methodName) logger req
-      | Propagate error -> setJsonBody resp (Errors.propagated error) logger req
+      | Ignore -> setJsonBody backend resp (Errors.ignored routeInfo.methodName) logger req
+      | Propagate error -> setJsonBody backend resp (Errors.propagated error) logger req
 
   let halt: HttpResponseData option = None
 

Fable.Remoting.AwsLambda/FableLambdaApiGatewayAdapter.fs

@@ -38,14 +38,15 @@ module private FuncsUtil =
   let private path (r: HttpRequestData) = r.Path
 
   let setJsonBody
+    (backend: JsonSerializerBackend)
     (res: HttpResponseData)
     (response: obj)
     (logger: Option<string -> unit>)
     (req: HttpRequestData)
     : Task<HttpResponseData option> =
     task {
       use ms = new MemoryStream()
-      jsonSerialize response ms
+      jsonSerializeWithBackend backend response ms
       let responseBody = System.Text.Encoding.UTF8.GetString(ms.ToArray())
       Diagnostics.outputPhase logger responseBody
       res.Headers <- dict [("Content-Type", "application/json; charset=utf-8" )]
@@ -62,13 +63,14 @@ module private FuncsUtil =
     : Task<HttpResponseData option> =
     let resp = HttpResponseData(StatusCode = int HttpStatusCode.InternalServerError)
     let logger = options.DiagnosticsLogger
+    let backend = options.JsonSerializer
 
     match options.ErrorHandler with
-    | None -> setJsonBody resp (Errors.unhandled routeInfo.methodName) logger req
+    | None -> setJsonBody backend resp (Errors.unhandled routeInfo.methodName) logger req
     | Some errorHandler ->
       match errorHandler ex routeInfo with
-      | Ignore -> setJsonBody resp (Errors.ignored routeInfo.methodName) logger req
-      | Propagate error -> setJsonBody resp (Errors.propagated error) logger req
+      | Ignore -> setJsonBody backend resp (Errors.ignored routeInfo.methodName) logger req
+      | Propagate error -> setJsonBody backend resp (Errors.propagated error) logger req
 
   let halt: HttpResponseData option = None
 

Fable.Remoting.AzureFunctions.Worker.Tests/Client/AdapterTests.fs

@@ -1,5 +1,11 @@
 module AdapterTests
 
+// Legacy Newtonsoft path tests for the AzureFunctions adapter. Requires a
+// manually-running FunctionApp on localhost:7071. The STJ-default path is
+// covered by the Phase 4b/4d HTTP integration tests in Giraffe/Suave/Falco
+// (the adapter code uses the identical setBody-with-backend pattern).
+#nowarn "44"
+
 open System
 open System.Net.Http
 open Expecto

Fable.Remoting.AzureFunctions.Worker/FableAzureFunctionsAdapter.fs

@@ -32,10 +32,10 @@ module private FuncsUtil =
 
     let private path (r:HttpRequestData) = r.Url.PathAndQuery.Split("?").[0]
 
-    let setJsonBody (res:HttpResponseData) (response: obj) (logger: Option<string -> unit>) (req:HttpRequestData) : Task<HttpResponseData option> =
+    let setJsonBody (backend: JsonSerializerBackend) (res:HttpResponseData) (response: obj) (logger: Option<string -> unit>) (req:HttpRequestData) : Task<HttpResponseData option> =
         task {
             use ms = new MemoryStream ()
-            jsonSerialize response ms
+            jsonSerializeWithBackend backend response ms
             let responseBody = System.Text.Encoding.UTF8.GetString (ms.ToArray ())
             Diagnostics.outputPhase logger responseBody
             let res = res |> setContentType "application/json; charset=utf-8"
@@ -47,12 +47,13 @@ module private FuncsUtil =
     let fail (ex: exn) (routeInfo: RouteInfo<HttpRequestData>) (options: RemotingOptions<HttpRequestData, 't>) (req:HttpRequestData) : Task<HttpResponseData option> =
         let resp = req.CreateResponse(HttpStatusCode.InternalServerError)
         let logger = options.DiagnosticsLogger
+        let backend = options.JsonSerializer
         match options.ErrorHandler with
-        | None -> setJsonBody resp (Errors.unhandled routeInfo.methodName) logger req
+        | None -> setJsonBody backend resp (Errors.unhandled routeInfo.methodName) logger req
         | Some errorHandler ->
             match errorHandler ex routeInfo with
-            | Ignore -> setJsonBody resp (Errors.ignored routeInfo.methodName) logger req
-            | Propagate error -> setJsonBody resp (Errors.propagated error) logger req
+            | Ignore -> setJsonBody backend resp (Errors.ignored routeInfo.methodName) logger req
+            | Propagate error -> setJsonBody backend resp (Errors.propagated error) logger req
 
     let halt: HttpResponseData option = None
 

Fable.Remoting.Benchmarks/Serialization.fs

@@ -1,5 +1,10 @@
 module Serialization
 
+// Benchmarks for the legacy Newtonsoft path. STJ-default benchmarks would
+// be a follow-up — left here as a reference point for any future
+// retirement-PR performance comparison.
+#nowarn "44"
+
 open BenchmarkDotNet.Attributes
 open Fable.Remoting.Json
 open Newtonsoft.Json