Scripts can override content type

Author: Bernt Røskar Brenna

UnitTests/TestDynamicResponse.cs

@@ -188,6 +188,29 @@ public async Task ScriptsCanSetResponseStatusCode()
 
             Assert.Equal(102, (int) response.HttpStatusCode);
         }
+
+        [Fact]
+        public async Task ScriptsCanSetContentType()
+        {
+            var endpoint = new Endpoint("foo", "bar");
+            var responseCreator = new LiteralDynamicResponseCreator("ContentType = \"image/png\"; return \"\";", endpoint);
+            var response = new TestableHttpResponse();
+            await responseCreator.CreateResponseAsync(new TestableHttpRequest("/", null), new byte[0], response, endpoint);
+
+            Assert.Equal("image/png", response.ContentType);
+        }
+
+        [Fact]
+        public async Task ScriptWithoutReturnValueThrowsException()
+        {   
+            var endpoint = new Endpoint("foo", "bar");
+            var responseCreator = new LiteralDynamicResponseCreator("ContentType = \"image/png\";", endpoint);
+            var response = new TestableHttpResponse();
+            await Assert.ThrowsAsync(
+                typeof(ArgumentNullException),
+                async () => await responseCreator.CreateResponseAsync(new TestableHttpRequest("/", null), new byte[0], response, endpoint)
+            );
+        }
     }
 
     public class TestCheckScriptModifications : IDisposable

netmockery/DynamicResponseCreator.cs

@@ -151,6 +151,20 @@ protected override void SetStatusCode(RequestInfo requestInfo, IHttpResponseWrap
                 base.SetStatusCode(requestInfo, response);
             }                           
         }
+
+        protected override void SetContentType(RequestInfo requestInfo, IHttpResponseWrapper response)
+        {
+            Debug.Assert(requestInfo != null);
+            Debug.Assert(response != null);
+            if (requestInfo.ContentType != RequestInfo.USE_CONFIGURED_CONTENT_TYPE)
+            {
+                response.ContentType = requestInfo.ContentType;
+            }
+            else
+            {
+                base.SetContentType(requestInfo, response);
+            }            
+        }
     }
 
     public class LiteralDynamicResponseCreator : DynamicResponseCreatorBase

netmockery/ResponseCreator.cs

@@ -87,6 +87,7 @@ public interface IResponseCreatorWithFilename
     public class RequestInfo
     {
         public const int USE_CONFIGURED_STATUS_CODE = -1;
+        public const string USE_CONFIGURED_CONTENT_TYPE = null;
 
         private static object _locker = new object();
 
@@ -96,6 +97,7 @@ public class RequestInfo
         public string QueryString;
         public string RequestBody;
         public int StatusCode = USE_CONFIGURED_STATUS_CODE;
+        public string ContentType = USE_CONFIGURED_CONTENT_TYPE;
         public IHeaderDictionary Headers;
         public Endpoint Endpoint;
         public string EndpointDirectory => Endpoint.Directory;
@@ -213,16 +215,25 @@ public override async Task<byte[]> CreateResponseAsync(IHttpRequestWrapper reque
                 Endpoint = endpoint
             };
             var responseBody = await GetBodyAndExecuteReplacementsAsync(requestInfo);
+
+            SetContentType(requestInfo, response);
+            SetStatusCode(requestInfo, response);
+
+            await response.WriteAsync(responseBody, Encoding);
+            return Encoding.GetBytes(responseBody);
+        }
+
+        protected virtual void SetContentType(RequestInfo requestInfo, IHttpResponseWrapper response)
+        {
+            // extension point, override to add logic in inheritors.
+            // currently used by DynamicResponseCreator in order to let script code override content type
+
             if (ContentType != null)
             {
                 var contenttype = ContentType;
                 contenttype += $"; charset={Encoding.WebName}";
                 response.ContentType = contenttype;
             }
-
-            SetStatusCode(requestInfo, response);
-            await response.WriteAsync(responseBody, Encoding);
-            return Encoding.GetBytes(responseBody);
         }
 
         protected virtual void SetStatusCode(RequestInfo requestInfo, IHttpResponseWrapper response)