From 22298114d7d9d08cf10f0c64f2119b23fc0b20e0 Mon Sep 17 00:00:00 2001
From: Stef Heyenrath <Stef.Heyenrath@gmail.com>
Date: Wed, 28 Feb 2018 18:05:10 +0100
Subject: [PATCH] Fix ResponseMessageTransformer

---
 .../ResponseMessageTransformer.cs             | 20 +++++++++------
 .../ResponseWithBodyHandlebarsTests.cs        | 25 +++++++++++++++++++
 2 files changed, 37 insertions(+), 8 deletions(-)

diff --git a/src/WireMock.Net/Transformers/ResponseMessageTransformer.cs b/src/WireMock.Net/Transformers/ResponseMessageTransformer.cs
index 509c8ab2..9dd58d8d 100644
--- a/src/WireMock.Net/Transformers/ResponseMessageTransformer.cs
+++ b/src/WireMock.Net/Transformers/ResponseMessageTransformer.cs
@@ -21,15 +21,19 @@ namespace WireMock.Transformers
             var template = new { request = requestMessage };
 
             // Body
-            var templateBody = Handlebars.Compile(bodyIsJson ? JsonConvert.SerializeObject(original.BodyAsJson) : original.Body);
+            string body = bodyIsJson ? JsonConvert.SerializeObject(original.BodyAsJson) : original.Body;
+            if (body != null)
+            {
+                var templateBody = Handlebars.Compile(body);
 
-            if (!bodyIsJson)
-            {
-                responseMessage.Body = templateBody(template);
-            }
-            else
-            {
-                responseMessage.BodyAsJson = JsonConvert.DeserializeObject(templateBody(template));
+                if (!bodyIsJson)
+                {
+                    responseMessage.Body = templateBody(template);
+                }
+                else
+                {
+                    responseMessage.BodyAsJson = JsonConvert.DeserializeObject(templateBody(template));
+                }
             }
 
             // Headers
diff --git a/test/WireMock.Net.Tests/ResponseWithBodyHandlebarsTests.cs b/test/WireMock.Net.Tests/ResponseWithBodyHandlebarsTests.cs
index 0e987c5c..70840fe0 100644
--- a/test/WireMock.Net.Tests/ResponseWithBodyHandlebarsTests.cs
+++ b/test/WireMock.Net.Tests/ResponseWithBodyHandlebarsTests.cs
@@ -2,8 +2,10 @@
 using System.Collections.Generic;
 using System.Text;
 using System.Threading.Tasks;
+using Newtonsoft.Json;
 using NFluent;
 using WireMock.ResponseBuilders;
+using WireMock.Util;
 using Xunit;
 
 namespace WireMock.Net.Tests
@@ -12,6 +14,29 @@ namespace WireMock.Net.Tests
     {
         private const string ClientIp = "::1";
 
+        [Fact]
+        public async Task Response_ProvideResponse_Handlebars_WithBodyAsJson()
+        {
+            // given
+            string jsonString = "{ \"things\": [ { \"name\": \"RequiredThing\" }, { \"name\": \"Wiremock\" } ] }";
+            var bodyData = new BodyData
+            {
+                BodyAsJson = JsonConvert.DeserializeObject(jsonString),
+                Encoding = Encoding.UTF8
+            };
+            var request = new RequestMessage(new Uri("http://localhost/foo"), "POST", ClientIp, bodyData);
+
+            var response = Response.Create()
+                .WithBodyAsJson(new { x = "test {{request.url}}" })
+                .WithTransformer();
+
+            // act
+            var responseMessage = await response.ProvideResponseAsync(request);
+
+            // then
+            Check.That(JsonConvert.SerializeObject(responseMessage.BodyAsJson)).Equals("{\"x\":\"test http://localhost/foo\"}");
+        }
+
         [Fact]
         public async Task Response_ProvideResponse_Handlebars_UrlPathVerb()
         {