Add WithBodyAsJson builder method with accepts a Func (#881)

* Add WithBodyAsJson builder method with accepts a Func

* ut

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

@@ -1,6 +1,8 @@
 using System;
+using System.Collections.Generic;
 using System.Globalization;
 using System.IO;
+using System.Linq;
 using System.Net;
 using System.Threading.Tasks;
 using Newtonsoft.Json;
@@ -33,6 +35,11 @@ namespace WireMock.Net.ConsoleApplication
         }
     }
 
+    public class Todo
+    {
+        public int Id { get; set; }
+    }
+
     public static class MainApp
     {
         public static void Run()
@@ -54,6 +61,32 @@ namespace WireMock.Net.ConsoleApplication
             var s = WireMockServer.Start();
             s.Stop();
 
+            var todos = new Dictionary<int, Todo>();
+
+            var server = WireMockServer.Start();
+
+            server
+                .Given(Request.Create()
+                    .WithPath("todos")
+                    .UsingGet()
+                )
+                .RespondWith(Response.Create()
+                    .WithBodyAsJson(todos.Values)
+                );
+
+            server
+                .Given(Request.Create()
+                    .UsingGet()
+                    .WithPath("todos")
+                    .WithParam("id")
+                )
+                .RespondWith(Response.Create()
+                    .WithBodyAsJson(rm => todos[int.Parse(rm.Query!["id"].ToString())])
+                );
+
+            var httpClient = server.CreateClient();
+            //server.Stop();
+            
             var httpAndHttpsWithPort = WireMockServer.Start(new WireMockServerSettings
             {
                 HostingScheme = HostingScheme.HttpAndHttps,
@@ -71,7 +104,7 @@ namespace WireMock.Net.ConsoleApplication
             string url2 = "http://localhost:9092/";
             string url3 = "https://localhost:9443/";
 
-            var server = WireMockServer.Start(new WireMockServerSettings
+            server = WireMockServer.Start(new WireMockServerSettings
             {
                 AllowCSharpCodeMatcher = true,
                 Urls = new[] { url1, url2, url3 },

src/WireMock.Net/ResponseBuilders/IBodyResponseBuilder.cs

@@ -29,7 +29,7 @@ public interface IBodyResponseBuilder : IFaultResponseBuilder
     IResponseBuilder WithBody(Func<IRequestMessage, string> bodyFactory, string? destination = BodyDestinationFormat.SameAsSource, Encoding? encoding = null);
 
     /// <summary>
-    /// WithBody : Create a ... response based on a callback function.
+    /// WithBody : Create a ... response based on a async callback function.
     /// </summary>
     /// <param name="bodyFactory">The async delegate to build the body.</param>
     /// <param name="destination">The Body Destination format (SameAsSource, String or Bytes).</param>
@@ -63,6 +63,22 @@ public interface IBodyResponseBuilder : IFaultResponseBuilder
     /// <returns>A <see cref="IResponseBuilder"/>.</returns>
     IResponseBuilder WithBodyAsJson(object body, bool indented);
 
+    /// <summary>
+    /// WithBodyAsJson : Create a ... response based on a callback function.
+    /// </summary>
+    /// <param name="bodyFactory">The delegate to build the body.</param>
+    /// <param name="encoding">The body encoding.</param>
+    /// <returns>A <see cref="IResponseBuilder"/>.</returns>
+    IResponseBuilder WithBodyAsJson(Func<IRequestMessage, object> bodyFactory, Encoding? encoding = null);
+
+    /// <summary>
+    /// WithBodyAsJson : Create a ... response based on a async callback function.
+    /// </summary>
+    /// <param name="bodyFactory">The async delegate to build the body.</param>
+    /// <param name="encoding">The body encoding.</param>
+    /// <returns>A <see cref="IResponseBuilder"/>.</returns>
+    IResponseBuilder WithBodyAsJson(Func<IRequestMessage, Task<object>> bodyFactory, Encoding? encoding = null);
+
     /// <summary>
     /// WithBodyFromFile : Create a ... response based on a File.
     /// </summary>

src/WireMock.Net/ResponseBuilders/Response.WithBody.cs

@@ -13,7 +13,7 @@ public partial class Response
     /// <inheritdoc />
     public IResponseBuilder WithBody(Func<IRequestMessage, string> bodyFactory, string? destination = BodyDestinationFormat.SameAsSource, Encoding? encoding = null)
     {
-        Guard.NotNull(bodyFactory, nameof(bodyFactory));
+        Guard.NotNull(bodyFactory);
 
         return WithCallbackInternal(true, req => new ResponseMessage
         {
@@ -30,7 +30,7 @@ public partial class Response
     /// <inheritdoc />
     public IResponseBuilder WithBody(Func<IRequestMessage, Task<string>> bodyFactory, string? destination = BodyDestinationFormat.SameAsSource, Encoding? encoding = null)
     {
-        Guard.NotNull(bodyFactory, nameof(bodyFactory));
+        Guard.NotNull(bodyFactory);
 
         return WithCallbackInternal(true, async req => new ResponseMessage
         {
@@ -70,7 +70,7 @@ public partial class Response
         return this;
     }
 
-    /// <inheritdoc cref="IBodyResponseBuilder.WithBodyFromFile"/>
+    /// <inheritdoc />
     public IResponseBuilder WithBodyFromFile(string filename, bool cache = true)
     {
         Guard.NotNull(filename);
@@ -127,7 +127,7 @@ public partial class Response
         return this;
     }
 
-    /// <inheritdoc cref="IBodyResponseBuilder.WithBodyAsJson(object, Encoding, bool?)"/>
+    /// <inheritdoc />
     public IResponseBuilder WithBodyAsJson(object body, Encoding? encoding = null, bool? indented = null)
     {
         Guard.NotNull(body);
@@ -144,12 +144,46 @@ public partial class Response
         return this;
     }
 
-    /// <inheritdoc cref="IBodyResponseBuilder.WithBodyAsJson(object, bool)"/>
+    /// <inheritdoc />
     public IResponseBuilder WithBodyAsJson(object body, bool indented)
     {
         return WithBodyAsJson(body, null, indented);
     }
 
+    /// <inheritdoc />
+    public IResponseBuilder WithBodyAsJson(Func<IRequestMessage, object> bodyFactory, Encoding? encoding = null)
+    {
+        Guard.NotNull(bodyFactory);
+
+        return WithCallbackInternal(true, req => new ResponseMessage
+        {
+            BodyData = new BodyData
+            {
+                Encoding = encoding ?? Encoding.UTF8,
+                DetectedBodyType = BodyType.Json,
+                BodyAsJson = bodyFactory(req),
+                IsFuncUsed = "Func<IRequestMessage, object>"
+            }
+        });
+    }
+
+    /// <inheritdoc />
+    public IResponseBuilder WithBodyAsJson(Func<IRequestMessage, Task<object>> bodyFactory, Encoding? encoding = null)
+    {
+        Guard.NotNull(bodyFactory);
+
+        return WithCallbackInternal(true, async req => new ResponseMessage
+        {
+            BodyData = new BodyData
+            {
+                Encoding = encoding ?? Encoding.UTF8,
+                DetectedBodyType = BodyType.Json,
+                BodyAsJson = await bodyFactory(req).ConfigureAwait(false),
+                IsFuncUsed = "Func<IRequestMessage, Task<object>>"
+            }
+        });
+    }
+
     /// <inheritdoc />
     public IResponseBuilder WithBody(object body, IJsonConverter converter, JsonConverterOptions? options = null)
     {

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

@@ -120,28 +120,6 @@ public class ResponseWithBodyTests
         Check.That(response.Message.BodyData.Encoding).Equals(Encoding.ASCII);
     }
 
-    [Fact]
-    public async Task Response_ProvideResponse_WithBody_Object_Indented()
-    {
-        // given
-        var body = new BodyData
-        {
-            DetectedBodyType = BodyType.String,
-            BodyAsString = "abc"
-        };
-        var request = new RequestMessage(new UrlDetails("http://localhost/foo"), "POST", ClientIp, body);
-
-        object x = new { message = "Hello" };
-        var responseBuilder = Response.Create().WithBodyAsJson(x, true);
-
-        // act
-        var response = await responseBuilder.ProvideResponseAsync(_mappingMock.Object, request, _settings).ConfigureAwait(false);
-
-        // then
-        Check.That(response.Message.BodyData.BodyAsJson).Equals(x);
-        Check.That(response.Message.BodyData.BodyAsJsonIndented).IsEqualTo(true);
-    }
-
     [Fact]
     public async Task Response_ProvideResponse_WithBody_String_SameAsSource_Encoding()
     {
@@ -196,6 +174,70 @@ public class ResponseWithBodyTests
         Check.That(response.Message.BodyData.Encoding).Equals(Encoding.ASCII);
     }
 
+    [Fact]
+    public async Task Response_ProvideResponse_WithBodyAsJson_Object_Indented()
+    {
+        // given
+        var body = new BodyData
+        {
+            DetectedBodyType = BodyType.String,
+            BodyAsString = "abc"
+        };
+        var request = new RequestMessage(new UrlDetails("http://localhost/foo"), "POST", ClientIp, body);
+
+        object x = new { message = "Hello" };
+        var responseBuilder = Response.Create().WithBodyAsJson(x, true);
+
+        // act
+        var response = await responseBuilder.ProvideResponseAsync(_mappingMock.Object, request, _settings).ConfigureAwait(false);
+
+        // then
+        Check.That(response.Message.BodyData.BodyAsJson).Equals(x);
+        Check.That(response.Message.BodyData.BodyAsJsonIndented).IsEqualTo(true);
+    }
+
+    [Fact]
+    public async Task Response_ProvideResponse_WithBodyAsJson_FuncObject()
+    {
+        // Arrange
+        var requestBody = new BodyData
+        {
+            DetectedBodyType = BodyType.String,
+            BodyAsString = "abc"
+        };
+        var request = new RequestMessage(new UrlDetails("http://localhost/foo"), "POST", ClientIp, requestBody);
+
+        object responseBody = new { message = "Hello" };
+        var responseBuilder = Response.Create().WithBodyAsJson(requestMessage => responseBody);
+
+        // Act
+        var response = await responseBuilder.ProvideResponseAsync(_mappingMock.Object, request, _settings).ConfigureAwait(false);
+
+        // Assert
+        response.Message.BodyData!.BodyAsJson.Should().BeEquivalentTo(responseBody);
+    }
+
+    [Fact]
+    public async Task Response_ProvideResponse_WithBodyAsJson_AsyncFuncObject()
+    {
+        // Arrange
+        var requestBody = new BodyData
+        {
+            DetectedBodyType = BodyType.String,
+            BodyAsString = "abc"
+        };
+        var request = new RequestMessage(new UrlDetails("http://localhost/foo"), "POST", ClientIp, requestBody);
+
+        object responseBody = new { message = "Hello" };
+        var responseBuilder = Response.Create().WithBodyAsJson(requestMessage => Task.FromResult(responseBody));
+
+        // Act
+        var response = await responseBuilder.ProvideResponseAsync(_mappingMock.Object, request, _settings).ConfigureAwait(false);
+
+        // Assert
+        response.Message.BodyData!.BodyAsJson.Should().BeEquivalentTo(responseBody);
+    }
+
     [Fact]
     public async Task Response_ProvideResponse_WithJsonBodyAndTransform()
     {