Allow setting Content-Length header on the response (#1158)

* Allow setting Content-Length header on the response

* fix?

examples/WireMock.Net.Console.Net452.Classic/MainApp.cs

@@ -137,7 +137,6 @@ message HelloReply {
         public static void Run()
         {
             RunOnLocal();
-            return;
 
             var mappingBuilder = new MappingBuilder();
             mappingBuilder
@@ -308,17 +307,6 @@ message HelloReply {
                 .RespondWith(Response.Create()
                     .WithBody("GraphQL is ok")
                 );
-
-            //server
-            //    .AddGraphQLSchema("my-graphql", TestSchema, customScalars)
-            //    .Given(Request.Create()
-            //        .WithPath("/graphql2")
-            //        .UsingPost()
-            //    )
-            //    .WithGraphQLSchema("my-graphql")
-            //    .RespondWith(Response.Create()
-            //        .WithBody("GraphQL is ok")
-            //    );
 #endif
 
 #if MIMEKIT
@@ -377,6 +365,15 @@ message HelloReply {
                         .WithHeader("Content-Type", "text/plain")
                 );
 
+            server
+                .Given(Request.Create()
+                    .UsingHead()
+                    .WithPath("/cl")
+                )
+                .RespondWith(Response.Create()
+                    .WithHeader("Content-Length", "42")
+                );
+
             server
                 .Given(Request.Create()
                     .UsingMethod("GET")

src/WireMock.Net/Http/HttpKnownHeaderNames.cs

@@ -14,12 +14,12 @@ namespace WireMock.Http;
 /// </summary>
 internal static class HttpKnownHeaderNames
 {
-    // https://docs.microsoft.com/en-us/dotnet/api/system.net.webheadercollection.isrestricted
+    // - https://docs.microsoft.com/en-us/dotnet/api/system.net.webheadercollection.isrestricted
+    // - ContentLength is allowed per #720
     private static readonly string[] RestrictedResponseHeaders =
     {
         Accept,
         Connection,
-        ContentLength,
         ContentType,
         Date, // RFC1123Pattern
         Expect,

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

@@ -37,12 +37,19 @@ namespace WireMock.Owin.Mappers
         private readonly Encoding _utf8NoBom = new UTF8Encoding(false);
 
         // https://msdn.microsoft.com/en-us/library/78h415ay(v=vs.110).aspx
-#if !USE_ASPNETCORE
+        private static readonly IDictionary<string, Action<IResponse, bool, WireMockList<string>>> ResponseHeadersToFix =
-        private static readonly IDictionary<string, Action<IResponse, WireMockList<string>>> ResponseHeadersToFix = new Dictionary<string, Action<IResponse, WireMockList<string>>>(StringComparer.OrdinalIgnoreCase) {
+            new Dictionary<string, Action<IResponse, bool, WireMockList<string>>>(StringComparer.OrdinalIgnoreCase)
-#else
+            {
-        private static readonly IDictionary<string, Action<IResponse, WireMockList<string>>> ResponseHeadersToFix = new Dictionary<string, Action<IResponse, WireMockList<string>>>(StringComparer.OrdinalIgnoreCase) {
+                { HttpKnownHeaderNames.ContentType, (r, _, v) => r.ContentType = v.FirstOrDefault() },
-#endif
+                { HttpKnownHeaderNames.ContentLength, (r, hasBody, v) =>
-            { HttpKnownHeaderNames.ContentType, (r, v) => r.ContentType = v.FirstOrDefault() }
+                    {
+                        // Only set the Content-Length header if the response does not have a body
+                        if (!hasBody && long.TryParse(v.FirstOrDefault(), out var contentLength))
+                        {
+                            r.ContentLength = contentLength;
+                        }
+                    }
+                }
             };
 
         /// <summary>
@@ -83,23 +90,21 @@ namespace WireMock.Owin.Mappers
             }
 
             var statusCodeType = responseMessage.StatusCode?.GetType();
-            switch (statusCodeType)
+            if (statusCodeType != null)
+            {
+                if (statusCodeType == typeof(int) || statusCodeType == typeof(int?) || statusCodeType.GetTypeInfo().IsEnum)
                 {
-                case { } when statusCodeType == typeof(int) || statusCodeType == typeof(int?) || statusCodeType.GetTypeInfo().IsEnum:
                     response.StatusCode = MapStatusCode((int)responseMessage.StatusCode!);
-                    break;
+                }
-
+                else if (statusCodeType == typeof(string))
-                case { } when statusCodeType == typeof(string):
+                {
                     // Note: this case will also match on null
-                    int.TryParse(responseMessage.StatusCode as string, out var result);
+                    int.TryParse(responseMessage.StatusCode as string, out var statusCodeTypeAsInt);
-                    response.StatusCode = MapStatusCode(result);
+                    response.StatusCode = MapStatusCode(statusCodeTypeAsInt);
-                    break;
+                }
-
-                default:
-                    break;
             }
 
-            SetResponseHeaders(responseMessage, response);
+            SetResponseHeaders(responseMessage, bytes, response);
 
             if (bytes != null)
             {
@@ -160,7 +165,7 @@ namespace WireMock.Owin.Mappers
             return null;
         }
 
-        private static void SetResponseHeaders(IResponseMessage responseMessage, IResponse response)
+        private static void SetResponseHeaders(IResponseMessage responseMessage, byte[]? bytes, IResponse response)
         {
             // Force setting the Date header (#577)
             AppendResponseHeader(
@@ -179,11 +184,11 @@ namespace WireMock.Owin.Mappers
                 var value = item.Value;
                 if (ResponseHeadersToFix.TryGetValue(headerName, out var action))
                 {
-                    action?.Invoke(response, value);
+                    action?.Invoke(response, bytes != null, value);
                 }
                 else
                 {
-                    // Check if this response header can be added (#148 and #227)
+                    // Check if this response header can be added (#148, #227 and #720)
                     if (!HttpKnownHeaderNames.IsRestrictedResponseHeader(headerName))
                     {
                         AppendResponseHeader(response, headerName, value.ToArray());
@@ -206,7 +211,7 @@ namespace WireMock.Owin.Mappers
                 var value = item.Value;
                 if (ResponseHeadersToFix.TryGetValue(headerName, out var action))
                 {
-                    action?.Invoke(response, value);
+                    action?.Invoke(response, false, value);
                 }
                 else
                 {

test/WireMock.Net.Tests/Owin/Mappers/OwinResponseMapperTests.cs

@@ -25,8 +25,8 @@ using Response = Microsoft.AspNetCore.Http.HttpResponse;
 using Microsoft.Extensions.Primitives;
 #endif
 
-namespace WireMock.Net.Tests.Owin.Mappers
+namespace WireMock.Net.Tests.Owin.Mappers;
-{
+
 public class OwinResponseMapperTests
 {
     private static readonly Task CompletedTask = Task.FromResult(true);
@@ -299,4 +299,3 @@ namespace WireMock.Net.Tests.Owin.Mappers
         _stream.Verify(s => s.WriteAsync(It.IsAny<byte[]>(), 0, It.Is<int>(count => count >= 0), It.IsAny<CancellationToken>()), Times.Once);
     }
 }
-}

test/WireMock.Net.Tests/WireMockServerTests.cs

@@ -14,6 +14,7 @@ using FluentAssertions;
 using Newtonsoft.Json;
 using NFluent;
 using WireMock.Admin.Mappings;
+using WireMock.Http;
 using WireMock.Matchers;
 using WireMock.Net.Tests.Serialization;
 using WireMock.Net.Xunit;
@@ -351,7 +352,7 @@ public partial class WireMockServerTests
     //}
 
     [Fact]
-    public async Task WireMockServer_Should_exclude_restrictedResponseHeader()
+    public async Task WireMockServer_Should_Exclude_RestrictedResponseHeader()
     {
         // Assign
         string path = $"/foo_{Guid.NewGuid()}";
@@ -371,6 +372,26 @@ public partial class WireMockServerTests
         server.Stop();
     }
 
+    [Fact] // #720
+    public async Task WireMockServer_Should_AllowResponseHeaderContentLength_For_HEAD()
+    {
+        // Assign
+        const string length = "42";
+        var path = $"/cl_{Guid.NewGuid()}";
+        using var server = WireMockServer.Start();
+
+        server
+            .Given(Request.Create().WithPath(path).UsingHead())
+            .RespondWith(Response.Create().WithHeader(HttpKnownHeaderNames.ContentLength, length));
+
+        // Act
+        var httpRequestMessage = new HttpRequestMessage(HttpMethod.Head, path);
+        var response = await server.CreateClient().SendAsync(httpRequestMessage).ConfigureAwait(false);
+
+        // Assert
+        response.Content.Headers.GetValues(HttpKnownHeaderNames.ContentLength).Should().Contain(length);
+    }
+
 #if !NET452 && !NET461
     [Theory]
     [InlineData("TRACE")]