Allow setting Content-Length header on the response

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

@@ -137,7 +137,6 @@ private static void RunOnLocal()
         public static void Run()
         {
             RunOnLocal();
-            return;
 
             var mappingBuilder = new MappingBuilder();
             mappingBuilder
@@ -308,17 +307,6 @@ public static void Run()
                 .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 @@ public static void Run()
                         .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 +37,17 @@ internal class OwinResponseMapper : IOwinResponseMapper
         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, WireMockList<string>>> ResponseHeadersToFix = new Dictionary<string, Action<IResponse, WireMockList<string>>>(StringComparer.OrdinalIgnoreCase) {
-#else
-        private static readonly IDictionary<string, Action<IResponse, WireMockList<string>>> ResponseHeadersToFix = new Dictionary<string, Action<IResponse, WireMockList<string>>>(StringComparer.OrdinalIgnoreCase) {
-#endif
-            { HttpKnownHeaderNames.ContentType, (r, v) => r.ContentType = v.FirstOrDefault() }
+        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() },
+            { HttpKnownHeaderNames.ContentLength, (r, v) =>
+                {
+                    if (long.TryParse(v.FirstOrDefault(), out var contentLength))
+                    {
+                        r.ContentLength = contentLength;
+                    }
+                }
+            }
         };
 
         /// <summary>
@@ -83,20 +88,16 @@ public async Task MapAsync(IResponseMessage? responseMessage, IResponse response
             }
 
             var statusCodeType = responseMessage.StatusCode?.GetType();
-            switch (statusCodeType)
+            if (statusCodeType != null)
             {
-                case { } when statusCodeType == typeof(int) || statusCodeType == typeof(int?) || statusCodeType.GetTypeInfo().IsEnum:
+                if (statusCodeType == typeof(int) || statusCodeType == typeof(int?) || statusCodeType.GetTypeInfo().IsEnum)
+                {
                     response.StatusCode = MapStatusCode((int)responseMessage.StatusCode!);
-                    break;
-
-                case { } when statusCodeType == typeof(string):
-                    // Note: this case will also match on null 
-                    int.TryParse(responseMessage.StatusCode as string, out var result);
-                    response.StatusCode = MapStatusCode(result);
-                    break;
-
-                default:
-                    break;
+                }
+                else if (statusCodeType == typeof(string) && int.TryParse(responseMessage.StatusCode as string, out var statusCodeTypeAsInt))
+                {
+                    response.StatusCode = MapStatusCode(statusCodeTypeAsInt);
+                }
             }
 
             SetResponseHeaders(responseMessage, response);
@@ -183,7 +184,7 @@ private static void SetResponseHeaders(IResponseMessage responseMessage, IRespon
                 }
                 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());