Attempt to fix JSON parsing of text/plain content type (#1172)

* UseContentType

* Fix unit tests

* Add a unit test and an integration test for the fix.

* Simplify body type checking with GetBodyType extension.

* Split IBodyDataExtension, and use imperative style instead of functional style

* Remove excessive null forgiving operators

* Adjust braces

---------

Co-authored-by: Ruxo Zheng <rz@just.sent.as>

src/WireMock.Net.Abstractions/Models/IBodyDataExtension.cs

@@ -0,0 +1,20 @@
+using WireMock.Types;
+
+// ReSharper disable once CheckNamespace
+namespace WireMock.Util;
+
+public static class IBodyDataExtension
+{
+    public static BodyType GetBodyType(this IBodyData bodyData)
+    {
+        if (bodyData.DetectedBodyTypeFromContentType is not null and not BodyType.None)
+        {
+            return bodyData.DetectedBodyTypeFromContentType.Value;
+        }
+        if (bodyData.DetectedBodyType is not null and not BodyType.None)
+        {
+            return bodyData.DetectedBodyType.Value;
+        }
+        return BodyType.None;
+    }
+}

src/WireMock.Net/Http/HttpRequestMessageHelper.cs

@@ -9,6 +9,7 @@ using Newtonsoft.Json;
 using Stef.Validation;
 using WireMock.Constants;
 using WireMock.Types;
+using WireMock.Util;
 
 namespace WireMock.Http;
 
@@ -33,12 +34,14 @@ internal static class HttpRequestMessageHelper
             MediaTypeHeaderValue.TryParse(value, out contentType);
         }
 
-        httpRequestMessage.Content = requestMessage.BodyData?.DetectedBodyType switch
+        var bodyData = requestMessage.BodyData;
+        httpRequestMessage.Content = bodyData?.GetBodyType() switch
         {
-            BodyType.Bytes => ByteArrayContentHelper.Create(requestMessage.BodyData.BodyAsBytes!, contentType),
-            BodyType.Json => StringContentHelper.Create(JsonConvert.SerializeObject(requestMessage.BodyData.BodyAsJson), contentType),
-            BodyType.String => StringContentHelper.Create(requestMessage.BodyData.BodyAsString!, contentType),
-            BodyType.FormUrlEncoded => StringContentHelper.Create(requestMessage.BodyData.BodyAsString!, contentType),
+            BodyType.Bytes => ByteArrayContentHelper.Create(bodyData!.BodyAsBytes!, contentType),
+            BodyType.Json => StringContentHelper.Create(JsonConvert.SerializeObject(bodyData!.BodyAsJson), contentType),
+            BodyType.String => StringContentHelper.Create(bodyData!.BodyAsString!, contentType),
+            BodyType.FormUrlEncoded => StringContentHelper.Create(bodyData!.BodyAsString!, contentType),
+
             _ => httpRequestMessage.Content
         };
 

src/WireMock.Net/Owin/Mappers/OwinResponseMapper.cs

@@ -19,6 +19,7 @@ using WireMock.Util;
 
 #if !USE_ASPNETCORE
 using IResponse = Microsoft.Owin.IOwinResponse;
+#pragma warning disable CS1998 // Async method lacks 'await' operators and will run synchronously
 #else
 using Microsoft.AspNetCore.Http;
 using IResponse = Microsoft.AspNetCore.Http.HttpResponse;
@@ -136,30 +137,37 @@ namespace WireMock.Owin.Mappers
             return responseMessage.FaultPercentage == null || _randomizerDouble.Generate() <= responseMessage.FaultPercentage;
         }
 
-        private async Task<byte[]?> GetNormalBodyAsync(IResponseMessage responseMessage)
-        {
-            switch (responseMessage.BodyData?.DetectedBodyType)
+        private async Task<byte[]?> GetNormalBodyAsync(IResponseMessage responseMessage) {
+            var bodyData = responseMessage.BodyData;
+            switch (bodyData?.GetBodyType())
             {
                 case BodyType.String:
                 case BodyType.FormUrlEncoded:
-                    return (responseMessage.BodyData.Encoding ?? _utf8NoBom).GetBytes(responseMessage.BodyData.BodyAsString!);
+                    return (bodyData!.Encoding ?? _utf8NoBom).GetBytes(bodyData.BodyAsString!);
 
                 case BodyType.Json:
-                    var formatting = responseMessage.BodyData.BodyAsJsonIndented == true ? Formatting.Indented : Formatting.None;
-                    var jsonBody = JsonConvert.SerializeObject(responseMessage.BodyData.BodyAsJson, new JsonSerializerSettings { Formatting = formatting, NullValueHandling = NullValueHandling.Ignore });
-                    return (responseMessage.BodyData.Encoding ?? _utf8NoBom).GetBytes(jsonBody);
+                    var formatting = bodyData!.BodyAsJsonIndented == true ? Formatting.Indented : Formatting.None;
+                    var jsonBody = JsonConvert.SerializeObject(bodyData.BodyAsJson, new JsonSerializerSettings { Formatting = formatting, NullValueHandling = NullValueHandling.Ignore });
+                    return (bodyData.Encoding ?? _utf8NoBom).GetBytes(jsonBody);
 
 #if PROTOBUF
                 case BodyType.ProtoBuf:
-                    var protoDefinition = responseMessage.BodyData.ProtoDefinition?.Invoke().Text;
-                    return await ProtoBufUtils.GetProtoBufMessageWithHeaderAsync(protoDefinition, responseMessage.BodyData.ProtoBufMessageType, responseMessage.BodyData.BodyAsJson).ConfigureAwait(false);
+                    var protoDefinition = bodyData!.ProtoDefinition?.Invoke().Text;
+                    return await ProtoBufUtils.GetProtoBufMessageWithHeaderAsync(protoDefinition, bodyData!.ProtoBufMessageType, bodyData!.BodyAsJson).ConfigureAwait(false);
 #endif
 
                 case BodyType.Bytes:
-                    return responseMessage.BodyData.BodyAsBytes;
+                    return bodyData!.BodyAsBytes;
 
                 case BodyType.File:
-                    return _options.FileSystemHandler?.ReadResponseBodyAsFile(responseMessage.BodyData.BodyAsFile!);
+                    return _options.FileSystemHandler?.ReadResponseBodyAsFile(bodyData!.BodyAsFile!);
+
+                case BodyType.MultiPart:
+                    _options.Logger.Warn("MultiPart body type is not handled!");
+                    break;
+
+                case BodyType.None:
+                    break;
             }
 
             return null;

test/WireMock.Net.Tests/Http/HttpRequestMessageHelperTests.cs

@@ -49,6 +49,26 @@ public class HttpRequestMessageHelperTests
         Check.That(await message.Content.ReadAsByteArrayAsync().ConfigureAwait(false)).ContainsExactly(Encoding.UTF8.GetBytes("hi"));
     }
 
+    [Fact]
+    public async Task HttpRequestMessageHelper_Create_TextPlain()
+    {
+        // Assign
+        var body = new BodyData
+        {
+            BodyAsString = "0123", // or 83 in decimal
+            BodyAsJson = 83,
+            DetectedBodyType = BodyType.Json,
+            DetectedBodyTypeFromContentType = BodyType.String
+        };
+        var request = new RequestMessage(new UrlDetails("http://localhost/foo"), "GET", ClientIp, body);
+
+        // Act
+        var message = HttpRequestMessageHelper.Create(request, "http://url");
+
+        // Assert
+        Check.That(await message.Content!.ReadAsStringAsync().ConfigureAwait(false)).Equals("0123");
+    }
+
     [Fact]
     public async Task HttpRequestMessageHelper_Create_Json()
     {
@@ -64,7 +84,7 @@ public class HttpRequestMessageHelperTests
         var message = HttpRequestMessageHelper.Create(request, "http://url");
 
         // Assert
-        Check.That(await message.Content.ReadAsStringAsync().ConfigureAwait(false)).Equals("{\"x\":42}");
+        Check.That(await message.Content!.ReadAsStringAsync().ConfigureAwait(false)).Equals("{\"x\":42}");
     }
 
     [Fact]

test/WireMock.Net.Tests/ResponseBuilders/ResponseWithProxyIntegrationTests.cs

@@ -0,0 +1,106 @@
+#if NET8_0_OR_GREATER
+
+using System;
+using System.IO;
+using System.Linq;
+using System.Net;
+using System.Net.Http;
+using System.Net.Http.Headers;
+using System.Text;
+using System.Threading.Tasks;
+using FluentAssertions;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Hosting.Server;
+using Microsoft.AspNetCore.Hosting.Server.Features;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using WireMock.Net.Xunit;
+using WireMock.RequestBuilders;
+using WireMock.ResponseBuilders;
+using WireMock.Server;
+using WireMock.Settings;
+using Xunit;
+using Xunit.Abstractions;
+
+namespace WireMock.Net.Tests.ResponseBuilders;
+
+public sealed class ResponseWithProxyIntegrationTests(ITestOutputHelper output)
+{
+    [Fact]
+    public async Task Response_UsingTextPlain()
+    {
+        // Given
+        using var server = await TestServer.New().Run();
+        var port = server.GetPort();
+        output.WriteLine($"Server running on port {port}");
+
+        var settings = new WireMockServerSettings {
+            Port = 0,
+            Logger = new TestOutputHelperWireMockLogger(output)
+        };
+        using var mockServer = WireMockServer.Start(settings);
+        mockServer.Given(Request.Create().WithPath("/zipcode").UsingPatch())
+                  .RespondWith(Response.Create().WithProxy($"http://localhost:{port}"));
+
+        using var client = new HttpClient { BaseAddress = new Uri(mockServer.Urls[0]) };
+        using var content = new ByteArrayContent(Encoding.UTF8.GetBytes("0123"));
+        content.Headers.ContentType = new MediaTypeHeaderValue("text/plain");
+
+        // When
+        var response = await client.PatchAsync("/zipcode", content);
+
+        // Then
+        response.StatusCode.Should().Be(HttpStatusCode.OK);
+        response.Content.Headers.GetValues("Content-Type").Should().BeEquivalentTo("text/plain; charset=utf-8");
+        var result = await response.Content.ReadAsStringAsync();
+        result.Should().Be("0123");
+    }
+
+    sealed class Disposable(Action dispose) : IDisposable
+    {
+        public void Dispose() => dispose();
+    }
+
+    sealed class TestServer(WebApplication app) : IDisposable
+    {
+        Disposable disposable = new(() => { });
+
+        public static TestServer New() {
+            var builder = WebApplication.CreateBuilder();
+            builder.WebHost.ConfigureKestrel(opts => opts.ListenAnyIP(0));
+
+            var app = builder.Build();
+
+            app.MapPatch("/zipcode", async (HttpRequest req) => {
+                var memory = new MemoryStream();
+                await req.Body.CopyToAsync(memory);
+                var content = Encoding.UTF8.GetString(memory.ToArray());
+                return content;
+            });
+            return new(app);
+        }
+
+        public int GetPort()
+            => app.Services.GetRequiredService<IServer>().Features.Get<IServerAddressesFeature>()!.Addresses
+                  .Select(x => new Uri(x).Port)
+                  .First();
+
+        public async ValueTask<TestServer> Run() {
+            var started = new TaskCompletionSource();
+            var host = app.Services.GetRequiredService<IHostApplicationLifetime>();
+            host.ApplicationStarted.Register(() => started.SetResult());
+            _ = Task.Run(() => app.RunAsync());
+            await started.Task;
+            disposable = new(() => host.StopApplication());
+            return this;
+        }
+
+        public void Dispose() {
+            disposable.Dispose();
+        }
+    }
+}
+
+#endif