Webhook (#591)

Webhook

examples/WireMock.Net.StandAlone.NETCoreApp/Program.cs

@@ -1,40 +1,40 @@
-using System;
-using System.IO;
-using System.Linq;
-using System.Reflection;
-using System.Threading;
-using log4net;
-using log4net.Config;
-using log4net.Repository;
-using WireMock.RequestBuilders;
-using WireMock.ResponseBuilders;
-using WireMock.Server;
-using WireMock.Settings;
+using System;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using System.Threading;
+using log4net;
+using log4net.Config;
+using log4net.Repository;
+using WireMock.RequestBuilders;
+using WireMock.ResponseBuilders;
+using WireMock.Server;
+using WireMock.Settings;
 using WireMock.Util;
-
-namespace WireMock.Net.StandAlone.NETCoreApp
-{
-    static class Program
-    {
-        private static readonly ILoggerRepository LogRepository = LogManager.GetRepository(Assembly.GetEntryAssembly());
-        // private static readonly ILog Log = LogManager.GetLogger(typeof(Program));
-
-        private static int sleepTime = 30000;
-        private static WireMockServer _server;
-
-        static void Main(string[] args)
-        {
-            XmlConfigurator.Configure(LogRepository, new FileInfo("log4net.config"));
-
+
+namespace WireMock.Net.StandAlone.NETCoreApp
+{
+    static class Program
+    {
+        private static readonly ILoggerRepository LogRepository = LogManager.GetRepository(Assembly.GetEntryAssembly());
+        // private static readonly ILog Log = LogManager.GetLogger(typeof(Program));
+
+        private static int sleepTime = 30000;
+        private static WireMockServer _server;
+
+        static void Main(string[] args)
+        {
+            XmlConfigurator.Configure(LogRepository, new FileInfo("log4net.config"));
+
             if (!WireMockServerSettingsParser.TryParseArguments(args, out var settings, new WireMockLog4NetLogger()))
             {
                 return;
             }
 
-            settings.Logger.Debug("WireMock.Net server arguments [{0}]", string.Join(", ", args.Select(a => $"'{a}'")));
-
-            _server = WireMockServer.Start(settings);
-
+            settings.Logger.Debug("WireMock.Net server arguments [{0}]", string.Join(", ", args.Select(a => $"'{a}'")));
+
+            _server = WireMockServer.Start(settings);
+
             _server.Given(Request.Create().WithPath("/api/sap")
                 .UsingPost()
                 .WithBody((IBodyData xmlData) => {
@@ -43,37 +43,37 @@ namespace WireMock.Net.StandAlone.NETCoreApp
                 }))
                 .RespondWith(Response.Create().WithStatusCode(System.Net.HttpStatusCode.OK));
 
-            _server
-                .Given(Request.Create()
-                    .UsingAnyMethod())
-                .RespondWith(Response.Create()
-                    .WithTransformer()
-                    .WithBody("{{Random Type=\"Integer\" Min=100 Max=999999}} {{DateTime.Now}} {{DateTime.Now \"yyyy-MMM\"}} {{String.Format (DateTime.Now) \"MMM-dd\"}}"));
-
-            Console.WriteLine($"{DateTime.UtcNow} Press Ctrl+C to shut down");
-
-            Console.CancelKeyPress += (s, e) =>
-            {
-                Stop("CancelKeyPress");
-            };
-
-            System.Runtime.Loader.AssemblyLoadContext.Default.Unloading += ctx =>
-            {
-                Stop("AssemblyLoadContext.Default.Unloading");
-            };
-
-            while (true)
-            {
-                Console.WriteLine($"{DateTime.UtcNow} WireMock.Net server running : {_server.IsStarted}");
-                Thread.Sleep(sleepTime);
-            }
-        }
-
-        private static void Stop(string why)
-        {
-            Console.WriteLine($"{DateTime.UtcNow} WireMock.Net server stopping because '{why}'");
-            _server.Stop();
-            Console.WriteLine($"{DateTime.UtcNow} WireMock.Net server stopped");
-        }
-    }
+            _server
+                .Given(Request.Create()
+                    .UsingAnyMethod())
+                .RespondWith(Response.Create()
+                    .WithTransformer()
+                    .WithBody("{{Random Type=\"Integer\" Min=100 Max=999999}} {{DateTime.Now}} {{DateTime.Now \"yyyy-MMM\"}} {{String.Format (DateTime.Now) \"MMM-dd\"}}"));
+
+            Console.WriteLine($"{DateTime.UtcNow} Press Ctrl+C to shut down");
+
+            Console.CancelKeyPress += (s, e) =>
+            {
+                Stop("CancelKeyPress");
+            };
+
+            System.Runtime.Loader.AssemblyLoadContext.Default.Unloading += ctx =>
+            {
+                Stop("AssemblyLoadContext.Default.Unloading");
+            };
+
+            while (true)
+            {
+                Console.WriteLine($"{DateTime.UtcNow} WireMock.Net server running : {_server.IsStarted}");
+                Thread.Sleep(sleepTime);
+            }
+        }
+
+        private static void Stop(string why)
+        {
+            Console.WriteLine($"{DateTime.UtcNow} WireMock.Net server stopping because '{why}'");
+            _server.Stop();
+            Console.WriteLine($"{DateTime.UtcNow} WireMock.Net server stopped");
+        }
+    }
 }

examples/WireMock.Net.StandAlone.NETCoreApp/Properties/launchSettings.json

@@ -2,7 +2,7 @@
   "profiles": {
     "WireMock.Net.StandAlone.NETCoreApp": {
       "commandName": "Project",
-      "commandLineArgs": "--Urls https://localhost:10080 --WireMockLogger WireMockConsoleLogger"
+      "commandLineArgs": "--Urls http://localhost:9091 --WireMockLogger WireMockConsoleLogger"
     }
   }
 }

src/WireMock.Net.Abstractions/Admin/Mappings/MappingModel.cs

@@ -52,5 +52,10 @@ namespace WireMock.Admin.Mappings
         /// Saves this mapping as a static mapping file.
         /// </summary>
         public bool? SaveToFile { get; set; }
+
+        /// <summary>
+        /// The Webhook.
+        /// </summary>
+        public WebhookModel Webhook { get; set; }
     }
 }

src/WireMock.Net.Abstractions/Admin/Mappings/ResponseModel.cs

@@ -1,5 +1,4 @@
 using System.Collections.Generic;
-using WireMock.Types;
 
 namespace WireMock.Admin.Mappings
 {

src/WireMock.Net.Abstractions/Admin/Mappings/WebhookModel.cs

@@ -0,0 +1,13 @@
+namespace WireMock.Admin.Mappings
+{
+    /// <summary>
+    /// The Webhook
+    /// </summary>
+    public class WebhookModel
+    {
+        /// <summary>
+        /// The Webhook Request.
+        /// </summary>
+        public WebhookRequestModel Request { get; set; }
+    }
+}

src/WireMock.Net.Abstractions/Admin/Mappings/WebhookRequestModel.cs

@@ -0,0 +1,45 @@
+using System.Collections.Generic;
+
+namespace WireMock.Admin.Mappings
+{
+    /// <summary>
+    /// RequestModel
+    /// </summary>
+    public class WebhookRequestModel
+    {
+        /// <summary>
+        /// Gets or sets the Url.
+        /// </summary>
+        public string Url { get; set; }
+
+        /// <summary>
+        /// The methods
+        /// </summary>
+        public string Method { get; set; }
+
+        /// <summary>
+        /// Gets or sets the headers.
+        /// </summary>
+        public IDictionary<string, string> Headers { get; set; }
+
+        /// <summary>
+        /// Gets or sets the body.
+        /// </summary>
+        public string Body { get; set; }
+
+        /// <summary>
+        /// Gets or sets the body (as JSON object).
+        /// </summary>
+        public object BodyAsJson { get; set; }
+
+        /// <summary>
+        /// Use ResponseMessage Transformer.
+        /// </summary>
+        public bool? UseTransformer { get; set; }
+
+        /// <summary>
+        /// Gets the type of the transformer.
+        /// </summary>
+        public string TransformerType { get; set; }
+    }
+}

src/WireMock.Net.Abstractions/Models/IWebhook.cs

@@ -0,0 +1,13 @@
+namespace WireMock.Models
+{
+    /// <summary>
+    /// IWebhook
+    /// </summary>
+    public interface IWebhook
+    {
+        /// <summary>
+        /// Request
+        /// </summary>
+        IWebhookRequest Request { get; set; }
+    }
+}

src/WireMock.Net.Abstractions/Models/IWebhookRequest.cs

@@ -0,0 +1,42 @@
+using System.Collections.Generic;
+using WireMock.Types;
+using WireMock.Util;
+
+namespace WireMock.Models
+{
+    /// <summary>
+    /// IWebhookRequest
+    /// </summary>
+    public interface IWebhookRequest
+    {
+        /// <summary>
+        /// The Webhook Url.
+        /// </summary>
+        string Url { get; set; }
+
+        /// <summary>
+        /// The method to use.
+        /// </summary>
+        string Method { get; set; }
+
+        /// <summary>
+        /// The Headers to send.
+        /// </summary>
+        IDictionary<string, WireMockList<string>> Headers { get; }
+
+        /// <summary>
+        /// The body to send.
+        /// </summary>
+        IBodyData BodyData { get; set; }
+
+        /// <summary>
+        /// Use Transformer.
+        /// </summary>
+        bool? UseTransformer { get; set; }
+
+        /// <summary>
+        /// The transformer type.
+        /// </summary>
+        TransformerType TransformerType { get; set; }
+    }
+}

src/WireMock.Net/Http/HttpClientBuilder.cs

@@ -7,7 +7,7 @@ namespace WireMock.Http
 {
     internal static class HttpClientBuilder
     {
-        public static HttpClient Build(IProxyAndRecordSettings settings)
+        public static HttpClient Build(IHttpClientSettings settings)
         {
 #if NETSTANDARD || NETCOREAPP3_1 || NET5_0
             var handler = new HttpClientHandler

src/WireMock.Net/Http/WebhookSender.cs

@@ -0,0 +1,85 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Http;
+using System.Threading.Tasks;
+using JetBrains.Annotations;
+using WireMock.Models;
+using WireMock.Settings;
+using WireMock.Transformers;
+using WireMock.Transformers.Handlebars;
+using WireMock.Transformers.Scriban;
+using WireMock.Types;
+using WireMock.Util;
+using WireMock.Validation;
+
+namespace WireMock.Http
+{
+    internal class WebhookSender
+    {
+        private const string ClientIp = "::1";
+
+        private readonly IWireMockServerSettings _settings;
+
+        public WebhookSender(IWireMockServerSettings settings)
+        {
+            _settings = settings ?? throw new ArgumentNullException(nameof(settings));
+        }
+
+        public Task<HttpResponseMessage> SendAsync([NotNull] HttpClient client, [NotNull] IWebhookRequest request, [NotNull] RequestMessage originalRequestMessage, [NotNull] ResponseMessage originalResponseMessage)
+        {
+            Check.NotNull(client, nameof(client));
+            Check.NotNull(request, nameof(request));
+            Check.NotNull(originalRequestMessage, nameof(originalRequestMessage));
+            Check.NotNull(originalResponseMessage, nameof(originalResponseMessage));
+
+            IBodyData bodyData;
+            IDictionary<string, WireMockList<string>> headers;
+            if (request.UseTransformer == true)
+            {
+                ITransformer responseMessageTransformer;
+                switch (request.TransformerType)
+                {
+                    case TransformerType.Handlebars:
+                        var factoryHandlebars = new HandlebarsContextFactory(_settings.FileSystemHandler, _settings.HandlebarsRegistrationCallback);
+                        responseMessageTransformer = new Transformer(factoryHandlebars);
+                        break;
+
+                    case TransformerType.Scriban:
+                    case TransformerType.ScribanDotLiquid:
+                        var factoryDotLiquid = new ScribanContextFactory(_settings.FileSystemHandler, request.TransformerType);
+                        responseMessageTransformer = new Transformer(factoryDotLiquid);
+                        break;
+
+                    default:
+                        throw new NotImplementedException($"TransformerType '{request.TransformerType}' is not supported.");
+                }
+
+                (bodyData, headers) = responseMessageTransformer.Transform(originalRequestMessage, originalResponseMessage, request.BodyData, request.Headers);
+            }
+            else
+            {
+                bodyData = request.BodyData;
+                headers = request.Headers;
+            }
+
+            // Create RequestMessage
+            var requestMessage = new RequestMessage(
+                new UrlDetails(request.Url),
+                request.Method,
+                ClientIp,
+                bodyData,
+                headers?.ToDictionary(x => x.Key, x => x.Value.ToArray())
+            )
+            {
+                DateTime = DateTime.UtcNow
+            };
+
+            // Create HttpRequestMessage
+            var httpRequestMessage = HttpRequestMessageHelper.Create(requestMessage, request.Url);
+
+            // Call the URL
+            return client.SendAsync(httpRequestMessage);
+        }
+    }
+}

src/WireMock.Net/IMapping.cs

@@ -2,6 +2,7 @@
 using System;
 using System.Threading.Tasks;
 using WireMock.Matchers.Request;
+using WireMock.Models;
 using WireMock.ResponseProviders;
 using WireMock.Settings;
 
@@ -93,6 +94,11 @@ namespace WireMock
         /// </value>
         bool LogMapping { get; }
 
+        /// <summary>
+        /// The Webhook.
+        /// </summary>
+        IWebhook Webhook { get; }
+
         /// <summary>
         /// ProvideResponseAsync
         /// </summary>

src/WireMock.Net/Mapping.cs

@@ -1,7 +1,9 @@
 using System;
 using System.Threading.Tasks;
 using JetBrains.Annotations;
+using WireMock.Admin.Mappings;
 using WireMock.Matchers.Request;
+using WireMock.Models;
 using WireMock.ResponseProviders;
 using WireMock.Settings;
 
@@ -54,6 +56,9 @@ namespace WireMock
         /// <inheritdoc cref="IMapping.LogMapping" />
         public bool LogMapping => !(Provider is DynamicResponseProvider || Provider is DynamicAsyncResponseProvider);
 
+        /// <inheritdoc cref="IMapping.Webhook" />
+        public IWebhook Webhook { get; }
+
         /// <summary>
         /// Initializes a new instance of the <see cref="Mapping"/> class.
         /// </summary>
@@ -68,6 +73,7 @@ namespace WireMock
         /// <param name="executionConditionState">State in which the current mapping can occur. [Optional]</param>
         /// <param name="nextState">The next state which will occur after the current mapping execution. [Optional]</param>
         /// <param name="stateTimes">Only when the current state is executed this number, the next state which will occur. [Optional]</param>
+        /// <param name="webhook">The Webhook. [Optional]</param>
         public Mapping(
             Guid guid,
             [CanBeNull] string title,
@@ -79,7 +85,8 @@ namespace WireMock
             [CanBeNull] string scenario,
             [CanBeNull] string executionConditionState,
             [CanBeNull] string nextState,
-            [CanBeNull] int? stateTimes)
+            [CanBeNull] int? stateTimes,
+            [CanBeNull] IWebhook webhook)
         {
             Guid = guid;
             Title = title;
@@ -92,6 +99,7 @@ namespace WireMock
             ExecutionConditionState = executionConditionState;
             NextState = nextState;
             StateTimes = stateTimes;
+            Webhook = webhook;
         }
 
         /// <inheritdoc cref="IMapping.ProvideResponseAsync" />

src/WireMock.Net/Models/BodyData.cs

@@ -6,7 +6,7 @@ namespace WireMock.Util
     /// <summary>
     /// BodyData
     /// </summary>
-    public class BodyData : IBodyData
+    internal class BodyData : IBodyData
     {
         /// <inheritdoc cref="IBodyData.Encoding" />
         public Encoding Encoding { get; set; }

src/WireMock.Net/Models/Webhook.cs

@@ -0,0 +1,15 @@
+using System.Collections.Generic;
+using JetBrains.Annotations;
+using WireMock.Types;
+
+namespace WireMock.Models
+{
+    /// <summary>
+    /// Webhook
+    /// </summary>
+    public class Webhook : IWebhook
+    {
+        /// <inheritdoc cref="IWebhook.Request"/>
+        public IWebhookRequest Request { get; set; }
+    }
+}

src/WireMock.Net/Models/WebhookRequest.cs

@@ -0,0 +1,30 @@
+using System.Collections.Generic;
+using WireMock.Types;
+using WireMock.Util;
+
+namespace WireMock.Models
+{
+    /// <summary>
+    /// WebhookRequest
+    /// </summary>
+    public class WebhookRequest : IWebhookRequest
+    {
+        /// <inheritdoc cref="IWebhookRequest.Url"/>
+        public string Url { get; set; }
+
+        /// <inheritdoc cref="IWebhookRequest.Method"/>
+        public string Method { get; set; }
+
+        /// <inheritdoc cref="IWebhookRequest.Headers"/>
+        public IDictionary<string, WireMockList<string>> Headers { get; set; }
+
+        /// <inheritdoc cref="IWebhookRequest.BodyData"/>
+        public IBodyData BodyData { get; set; }
+
+        /// <inheritdoc cref="IWebhookRequest.UseTransformer"/>
+        public bool? UseTransformer { get; set; }
+
+        /// <inheritdoc cref="IWebhookRequest.TransformerType"/>
+        public TransformerType TransformerType { get; set; }
+    }
+}

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

@@ -53,7 +53,7 @@ namespace WireMock.Owin.Mappers
                 }
             }
 
-            BodyData body = null;
+            IBodyData body = null;
             if (request.Body != null && BodyParser.ShouldParseBody(method, options.AllowBodyForAllHttpMethods == true))
             {
                 var bodyParserSettings = new BodyParserSettings

src/WireMock.Net/Owin/WireMockMiddleware.cs

@@ -9,6 +9,7 @@ using WireMock.Serialization;
 using WireMock.Types;
 using WireMock.Validation;
 using WireMock.ResponseBuilders;
+using WireMock.Settings;
 #if !USE_ASPNETCORE
 using Microsoft.Owin;
 using IContext = Microsoft.Owin.IOwinContext;
@@ -153,6 +154,11 @@ namespace WireMock.Owin
                 {
                     UpdateScenarioState(targetMapping);
                 }
+
+                if (!targetMapping.IsAdminInterface && targetMapping.Webhook != null)
+                {
+                    await SendToWebhookAsync(targetMapping, request, response).ConfigureAwait(false);
+                }
             }
             catch (Exception ex)
             {
@@ -184,6 +190,21 @@ namespace WireMock.Owin
             await CompletedTask;
         }
 
+        private async Task SendToWebhookAsync(IMapping mapping, RequestMessage request, ResponseMessage response)
+        {
+            var httpClientForWebhook = HttpClientBuilder.Build(mapping.Settings.WebhookSettings ?? new WebhookSettings());
+            var webhookSender = new WebhookSender(mapping.Settings);
+
+            try
+            {
+                await webhookSender.SendAsync(httpClientForWebhook, mapping.Webhook.Request, request, response).ConfigureAwait(false);
+            }
+            catch (Exception ex)
+            {
+                _options.Logger.Error($"Sending message to Webhook Mapping '{mapping.Guid}' failed. Exception: {ex}");
+            }
+        }
+
         private void UpdateScenarioState(IMapping mapping)
         {
             var scenario = _options.Scenarios[mapping.Scenario];

src/WireMock.Net/Proxy/ProxyHelper.cs

@@ -3,7 +3,6 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Net.Http;
 using System.Threading.Tasks;
-using HandlebarsDotNet.Helpers.Validation;
 using JetBrains.Annotations;
 using WireMock.Http;
 using WireMock.Matchers;
@@ -106,7 +105,7 @@ namespace WireMock.Proxy
 
             var response = Response.Create(responseMessage);
 
-            return new Mapping(Guid.NewGuid(), string.Empty, null, _settings, request, response, 0, null, null, null, null);
+            return new Mapping(Guid.NewGuid(), string.Empty, null, _settings, request, response, 0, null, null, null, null, null);
         }
     }
 }

src/WireMock.Net/RequestMessage.cs

@@ -101,7 +101,7 @@ namespace WireMock
         /// <param name="bodyData">The BodyData.</param>
         /// <param name="headers">The headers.</param>
         /// <param name="cookies">The cookies.</param>
-        public RequestMessage([NotNull] UrlDetails urlDetails, [NotNull] string method, [NotNull] string clientIP, [CanBeNull] BodyData bodyData = null, [CanBeNull] IDictionary<string, string[]> headers = null, [CanBeNull] IDictionary<string, string> cookies = null)
+        public RequestMessage([NotNull] UrlDetails urlDetails, [NotNull] string method, [NotNull] string clientIP, [CanBeNull] IBodyData bodyData = null, [CanBeNull] IDictionary<string, string[]> headers = null, [CanBeNull] IDictionary<string, string> cookies = null)
         {
             Check.NotNull(urlDetails, nameof(urlDetails));
             Check.NotNull(method, nameof(method));

src/WireMock.Net/Serialization/MappingConverter.cs

@@ -84,7 +84,8 @@ namespace WireMock.Serialization
                 Response = new ResponseModel
                 {
                     Delay = (int?)response.Delay?.TotalMilliseconds
-                }
+                },
+                Webhook = WebhookMapper.Map(mapping.Webhook)
             };
 
             if (bodyMatcher?.Matchers != null)

src/WireMock.Net/Serialization/WebhookMapper.cs

@@ -0,0 +1,103 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using WireMock.Admin.Mappings;
+using WireMock.Http;
+using WireMock.Models;
+using WireMock.Types;
+using WireMock.Util;
+
+namespace WireMock.Serialization
+{
+    internal static class WebhookMapper
+    {
+        public static IWebhook Map(WebhookModel model)
+        {
+            var webhook = new Webhook
+            {
+                Request = new WebhookRequest
+                {
+                    Url = model.Request.Url,
+                    Method = model.Request.Method,
+                    Headers = model.Request.Headers?.ToDictionary(x => x.Key, x => new WireMockList<string>(x.Value)) ?? new Dictionary<string, WireMockList<string>>()
+                }
+            };
+
+            if (model.Request.UseTransformer == true)
+            {
+                webhook.Request.UseTransformer = true;
+                if (!Enum.TryParse<TransformerType>(model.Request.TransformerType, out var transformerType))
+                {
+                    transformerType = TransformerType.Handlebars;
+                }
+                webhook.Request.TransformerType = transformerType;
+            }
+
+            IEnumerable<string> contentTypeHeader = null;
+            if (webhook.Request.Headers.Any(header => string.Equals(header.Key, HttpKnownHeaderNames.ContentType, StringComparison.OrdinalIgnoreCase)))
+            {
+                contentTypeHeader = webhook.Request.Headers.First(header => string.Equals(header.Key, HttpKnownHeaderNames.ContentType, StringComparison.OrdinalIgnoreCase)).Value;
+            }
+
+            if (model.Request.Body != null)
+            {
+                webhook.Request.BodyData = new BodyData
+                {
+                    BodyAsString = model.Request.Body,
+                    DetectedBodyType = BodyType.String,
+                    DetectedBodyTypeFromContentType = BodyParser.DetectBodyTypeFromContentType(contentTypeHeader?.FirstOrDefault())
+                };
+            }
+            else if (model.Request.BodyAsJson != null)
+            {
+                webhook.Request.BodyData = new BodyData
+                {
+                    BodyAsJson = model.Request.BodyAsJson,
+                    DetectedBodyType = BodyType.Json,
+                    DetectedBodyTypeFromContentType = BodyParser.DetectBodyTypeFromContentType(contentTypeHeader?.FirstOrDefault())
+                };
+            }
+
+            return webhook;
+        }
+
+        public static WebhookModel Map(IWebhook webhook)
+        {
+            if (webhook?.Request == null)
+            {
+                return null;
+            }
+
+            var model = new WebhookModel
+            {
+                Request = new WebhookRequestModel
+                {
+                    Url = webhook.Request.Url,
+                    Method = webhook.Request.Method,
+                    Headers = webhook.Request.Headers?.ToDictionary(x => x.Key, x => x.Value.ToString()),
+                    UseTransformer = webhook.Request.UseTransformer,
+                    TransformerType = webhook.Request.UseTransformer == true ? webhook.Request.TransformerType.ToString() : null
+                }
+            };
+
+            if (webhook.Request.BodyData != null)
+            {
+                switch (webhook.Request.BodyData.DetectedBodyType)
+                {
+                    case BodyType.String:
+                        model.Request.Body = webhook.Request.BodyData.BodyAsString;
+                        break;
+
+                    case BodyType.Json:
+                        model.Request.BodyAsJson = webhook.Request.BodyData.BodyAsJson;
+                        break;
+
+                    default:
+                        break;
+                }
+            }
+
+            return model;
+        }
+    }
+}

src/WireMock.Net/Server/IRespondWithAProvider.cs

@@ -1,5 +1,9 @@
 using System;
+using System.Collections.Generic;
+using JetBrains.Annotations;
+using WireMock.Models;
 using WireMock.ResponseProviders;
+using WireMock.Types;
 
 namespace WireMock.Server
 {
@@ -97,5 +101,50 @@ namespace WireMock.Server
         /// <param name="times">The number of times this match should be matched before the state will be changed to the specified one. Default value is 1.</param>
         /// <returns>The <see cref="IRespondWithAProvider"/>.</returns>
         IRespondWithAProvider WillSetStateTo(int state, int? times = 1);
+
+        /// <summary>
+        /// Add a Webbook to call after the response has been generated.
+        /// </summary>
+        /// <param name="webhook">The Webhook</param>
+        /// <returns>The <see cref="IRespondWithAProvider"/>.</returns>
+        IRespondWithAProvider WithWebhook(IWebhook webhook);
+
+        /// <summary>
+        /// Add a Webbook to call after the response has been generated.
+        /// </summary>
+        /// <param name="url">The Webhook Url</param>
+        /// <param name="method">The method to use. [optional]</param>
+        /// <param name="headers">The Headers to send. [optional]</param>
+        /// <param name="body">The body (as string) to send. [optional]</param>
+        /// <param name="useTransformer">Use Transformer. [optional]</param>
+        /// <param name="transformerType">The transformer type. [optional]</param>
+        /// <returns>The <see cref="IRespondWithAProvider"/>.</returns>
+        IRespondWithAProvider WithWebhook(
+            [NotNull] string url,
+            [CanBeNull] string method = "post",
+            [CanBeNull] IDictionary<string, WireMockList<string>> headers = null,
+            [CanBeNull] string body = null,
+            bool useTransformer = true,
+            TransformerType transformerType = TransformerType.Handlebars
+        );
+
+        /// <summary>
+        /// Add a Webbook to call after the response has been generated.
+        /// </summary>
+        /// <param name="url">The Webhook Url</param>
+        /// <param name="method">The method to use. [optional]</param>
+        /// <param name="headers">The Headers to send. [optional]</param>
+        /// <param name="body">The body (as json) to send. [optional]</param>
+        /// <param name="useTransformer">Use Transformer. [optional]</param>
+        /// <param name="transformerType">The transformer type. [optional]</param>
+        /// <returns>The <see cref="IRespondWithAProvider"/>.</returns>
+        IRespondWithAProvider WithWebhook(
+            [NotNull] string url,
+            [CanBeNull] string method = "post",
+            [CanBeNull] IDictionary<string, WireMockList<string>> headers = null,
+            [CanBeNull] object body = null,
+            bool useTransformer = true,
+            TransformerType transformerType = TransformerType.Handlebars
+        );
     }
 }

src/WireMock.Net/Server/RespondWithAProvider.cs

@@ -1,10 +1,15 @@
 // This source file is based on mock4net by Alexandre Victoor which is licensed under the Apache 2.0 License.
 // For more details see 'mock4net/LICENSE.txt' and 'mock4net/readme.md' in this project root.
 using System;
+using System.Collections.Generic;
+using JetBrains.Annotations;
 using WireMock.Matchers.Request;
+using WireMock.Models;
 using WireMock.ResponseProviders;
 using WireMock.Settings;
-
+using WireMock.Types;
+using WireMock.Util;
+
 namespace WireMock.Server
 {
     /// <summary>
@@ -26,6 +31,8 @@ namespace WireMock.Server
 
         public Guid Guid { get; private set; } = Guid.NewGuid();
 
+        public IWebhook Webhook { get; private set; }
+
         /// <summary>
         /// Initializes a new instance of the <see cref="RespondWithAProvider"/> class.
         /// </summary>
@@ -47,7 +54,7 @@ namespace WireMock.Server
         /// <param name="provider">The provider.</param>
         public void RespondWith(IResponseProvider provider)
         {
-            _registrationCallback(new Mapping(Guid, _title, _path, _settings, _requestMatcher, provider, _priority, _scenario, _executionConditionState, _nextState, _timesInSameState), _saveToFile);
+            _registrationCallback(new Mapping(Guid, _title, _path, _settings, _requestMatcher, provider, _priority, _scenario, _executionConditionState, _nextState, _timesInSameState, Webhook), _saveToFile);
         }
 
         /// <see cref="IRespondWithAProvider.WithGuid(string)"/>
@@ -140,5 +147,81 @@ namespace WireMock.Server
         {
             return WillSetStateTo(state.ToString(), times);
         }
+
+        /// <see cref="IRespondWithAProvider.WithWebhook(IWebhook)"/>
+        public IRespondWithAProvider WithWebhook(IWebhook webhook)
+        {
+            Webhook = webhook;
+
+            return this;
+        }
+
+        /// <see cref="IRespondWithAProvider.WithWebhook(string,string, IDictionary{string, WireMockList{string}}, string, bool, TransformerType)"/>
+        public IRespondWithAProvider WithWebhook(
+            [NotNull] string url,
+            [CanBeNull] string method = "post",
+            [CanBeNull] IDictionary<string, WireMockList<string>> headers = null,
+            [CanBeNull] string body = null,
+            bool useTransformer = true,
+            TransformerType transformerType = TransformerType.Handlebars)
+        {
+            Webhook = InitWebhook(url, method, headers, useTransformer, transformerType);
+
+            if (body != null)
+            {
+                Webhook.Request.BodyData = new BodyData
+                {
+                    BodyAsString = body,
+                    DetectedBodyType = BodyType.String,
+                    DetectedBodyTypeFromContentType = BodyType.String
+                };
+            }
+
+            return this;
+        }
+
+        /// <see cref="IRespondWithAProvider.WithWebhook(string, string, IDictionary{string, WireMockList{string}}, object, bool, TransformerType)"/>
+        public IRespondWithAProvider WithWebhook(
+            [NotNull] string url,
+            [CanBeNull] string method = "post",
+            [CanBeNull] IDictionary<string, WireMockList<string>> headers = null,
+            [CanBeNull] object body = null,
+            bool useTransformer = true,
+            TransformerType transformerType = TransformerType.Handlebars)
+        {
+            Webhook = InitWebhook(url, method, headers, useTransformer, transformerType);
+
+            if (body != null)
+            {
+                Webhook.Request.BodyData = new BodyData
+                {
+                    BodyAsJson = body,
+                    DetectedBodyType = BodyType.Json,
+                    DetectedBodyTypeFromContentType = BodyType.Json
+                };
+            }
+
+            return this;
+        }
+
+        private IWebhook InitWebhook(
+            string url,
+            string method,
+            IDictionary<string, WireMockList<string>> headers,
+            bool useTransformer,
+            TransformerType transformerType)
+        {
+            return new Webhook
+            {
+                Request = new WebhookRequest
+                {
+                    Url = url,
+                    Method = method ?? "post",
+                    Headers = headers,
+                    UseTransformer = useTransformer,
+                    TransformerType = transformerType
+                }
+            };
+        }
     }
 }

src/WireMock.Net/Server/WireMockServer.Admin.cs

@@ -470,6 +470,11 @@ namespace WireMock.Server
                 respondProvider = respondProvider.WillSetStateTo(mappingModel.SetStateTo);
             }
 
+            if (mappingModel.Webhook?.Request != null)
+            {
+                respondProvider = respondProvider.WithWebhook(WebhookMapper.Map(mappingModel.Webhook));
+            }
+
             respondProvider.RespondWith(responseBuilder);
 
             return respondProvider.Guid;

src/WireMock.Net/Settings/HttpClientSettings.cs

@@ -0,0 +1,17 @@
+namespace WireMock.Settings
+{
+    /// <summary>
+    /// HttpClientSettings
+    /// </summary>
+    public class HttpClientSettings : IHttpClientSettings
+    {
+        /// <inheritdoc cref="IHttpClientSettings.ClientX509Certificate2ThumbprintOrSubjectName"/>
+        public string ClientX509Certificate2ThumbprintOrSubjectName { get; set; }
+
+        /// <inheritdoc cref="IHttpClientSettings.WebProxySettings"/>
+        public IWebProxySettings WebProxySettings { get; set; }
+
+        /// <inheritdoc cref="IHttpClientSettings.AllowAutoRedirect"/>
+        public bool? AllowAutoRedirect { get; set; }
+    }
+}

src/WireMock.Net/Settings/IHttpClientSettings.cs

@@ -0,0 +1,24 @@
+namespace WireMock.Settings
+{
+    /// <summary>
+    /// IHttpClientSettings
+    /// </summary>
+    public interface IHttpClientSettings
+    {
+        /// <summary>
+        /// The clientCertificate thumbprint or subject name fragment to use.
+        /// Example thumbprint : "D2DBF135A8D06ACCD0E1FAD9BFB28678DF7A9818". Example subject name: "www.google.com""
+        /// </summary>
+        string ClientX509Certificate2ThumbprintOrSubjectName { get; set; }
+
+        /// <summary>
+        /// Defines the WebProxySettings.
+        /// </summary>
+        IWebProxySettings WebProxySettings { get; set; }
+
+        /// <summary>
+        /// Proxy requests should follow redirection (30x).
+        /// </summary>
+        bool? AllowAutoRedirect { get; set; }
+    }
+}

src/WireMock.Net/Settings/IProxyAndRecordSettings.cs

@@ -5,7 +5,7 @@ namespace WireMock.Settings
     /// <summary>
     /// IProxyAndRecordSettings
     /// </summary>
-    public interface IProxyAndRecordSettings
+    public interface IProxyAndRecordSettings : IHttpClientSettings
     {
         /// <summary>
         /// The URL to proxy.
@@ -29,12 +29,6 @@ namespace WireMock.Settings
         /// </summary>
         bool SaveMappingToFile { get; set; }
 
-        /// <summary>
-        /// The clientCertificate thumbprint or subject name fragment to use.
-        /// Example thumbprint : "D2DBF135A8D06ACCD0E1FAD9BFB28678DF7A9818". Example subject name: "www.google.com""
-        /// </summary>
-        string ClientX509Certificate2ThumbprintOrSubjectName { get; set; }
-
         /// <summary>
         /// Defines a list from headers which will be excluded from the saved mappings.
         /// </summary>
@@ -44,15 +38,5 @@ namespace WireMock.Settings
         /// Defines a list of cookies which will be excluded from the saved mappings.
         /// </summary>
         string[] ExcludedCookies { get; set; }
-
-        /// <summary>
-        /// Defines the WebProxySettings.
-        /// </summary>
-        IWebProxySettings WebProxySettings { get; set; }
-
-        /// <summary>
-        /// Proxy requests should follow redirection (30x).
-        /// </summary>
-        bool? AllowAutoRedirect { get; set; }
     }
 }

src/WireMock.Net/Settings/IWebhookSettings.cs

@@ -0,0 +1,9 @@
+namespace WireMock.Settings
+{
+    /// <summary>
+    /// IWebhookSettings
+    /// </summary>
+    public interface IWebhookSettings : IHttpClientSettings
+    {
+    }
+}

src/WireMock.Net/Settings/IWireMockServerSettings.cs

@@ -186,5 +186,11 @@ namespace WireMock.Settings
         /// </summary>
         [PublicAPI]
         bool CustomCertificateDefined { get; }
+
+        /// <summary>
+        /// Defines the global IWebhookSettingsto use
+        /// </summary>
+        [PublicAPI]
+        IWebhookSettings WebhookSettings { get; set; }
     }
 }

src/WireMock.Net/Settings/ProxyAndRecordSettings.cs

@@ -5,7 +5,7 @@ namespace WireMock.Settings
     /// <summary>
     /// ProxyAndRecordSettings
     /// </summary>
-    public class ProxyAndRecordSettings : IProxyAndRecordSettings
+    public class ProxyAndRecordSettings : HttpClientSettings, IProxyAndRecordSettings
     {
         /// <summary>
         /// The URL to proxy.
@@ -32,13 +32,6 @@ namespace WireMock.Settings
         [PublicAPI]
         public string SaveMappingForStatusCodePattern { get; set; } = "*";
 
-        /// <summary>
-        /// The clientCertificate thumbprint or subject name fragment to use.
-        /// Example thumbprint : "D2DBF135A8D06ACCD0E1FAD9BFB28678DF7A9818". Example subject name: "www.google.com""
-        /// </summary>
-        [PublicAPI]
-        public string ClientX509Certificate2ThumbprintOrSubjectName { get; set; }
-
         /// <inheritdoc cref="IProxyAndRecordSettings.ExcludedHeaders"/>
         [PublicAPI]
         public string[] ExcludedHeaders { get; set; }
@@ -46,13 +39,5 @@ namespace WireMock.Settings
         /// <inheritdoc cref="IProxyAndRecordSettings.ExcludedCookies"/>
         [PublicAPI]
         public string[] ExcludedCookies { get; set; }
-
-        /// <inheritdoc cref="IProxyAndRecordSettings.WebProxySettings"/>
-        [PublicAPI]
-        public IWebProxySettings WebProxySettings { get; set; }
-
-        /// <inheritdoc cref="IProxyAndRecordSettings.AllowAutoRedirect"/>
-        [PublicAPI]
-        public bool? AllowAutoRedirect { get; set; }
     }
 }

src/WireMock.Net/Settings/WebhookSettings.cs

@@ -0,0 +1,9 @@
+namespace WireMock.Settings
+{
+    /// <summary>
+    /// WebhookSettings
+    /// </summary>
+    public class WebhookSettings : HttpClientSettings, IWebhookSettings
+    {
+    }
+}

src/WireMock.Net/Settings/WireMockServerSettings.cs

@@ -129,5 +129,9 @@ namespace WireMock.Settings
         /// <inheritdoc cref="IWireMockServerSettings.CustomCertificateDefined"/>
         [PublicAPI]
         public bool CustomCertificateDefined => CertificateSettings?.IsDefined == true;
+
+        /// <inheritdoc cref="IWireMockServerSettings.WebhookSettings"/>
+        [PublicAPI]
+        public IWebhookSettings WebhookSettings { get; set; }
     }
 }

src/WireMock.Net/Transformers/ITransformer.cs

@@ -1,7 +1,13 @@
-namespace WireMock.Transformers
+using System.Collections.Generic;
+using WireMock.Types;
+using WireMock.Util;
+
+namespace WireMock.Transformers
 {
     interface ITransformer
     {
         ResponseMessage Transform(RequestMessage requestMessage, ResponseMessage original, bool useTransformerForBodyAsFile);
+
+        (IBodyData BodyData, IDictionary<string, WireMockList<string>> Headers) Transform(RequestMessage originalRequestMessage, ResponseMessage originalResponseMessage, IBodyData bodyData, IDictionary<string, WireMockList<string>> headers);
     }
 }

src/WireMock.Net/Transformers/Transformer.cs

@@ -1,227 +1,265 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using JetBrains.Annotations;
-using Newtonsoft.Json;
-using Newtonsoft.Json.Linq;
-using WireMock.Types;
-using WireMock.Util;
-using WireMock.Validation;
-
-namespace WireMock.Transformers.Handlebars
-{
-    internal class Transformer : ITransformer
-    {
-        private readonly ITransformerContextFactory _factory;
-
-        public Transformer([NotNull] ITransformerContextFactory factory)
-        {
-            Check.NotNull(factory, nameof(factory));
-
-            _factory = factory;
-        }
-
-        public ResponseMessage Transform(RequestMessage requestMessage, ResponseMessage original, bool useTransformerForBodyAsFile)
-        {
-            var handlebarsContext = _factory.Create();
-
-            var responseMessage = new ResponseMessage();
-
-            var model = new { request = requestMessage };
-
-            switch (original.BodyData?.DetectedBodyType)
-            {
-                case BodyType.Json:
-                    TransformBodyAsJson(handlebarsContext, model, original, responseMessage);
-                    break;
-
-                case BodyType.File:
-                    TransformBodyAsFile(handlebarsContext, model, original, responseMessage, useTransformerForBodyAsFile);
-                    break;
-
-                case BodyType.String:
-                    responseMessage.BodyOriginal = original.BodyData.BodyAsString;
-                    TransformBodyAsString(handlebarsContext, model, original, responseMessage);
-                    break;
-            }
-
-            responseMessage.FaultType = original.FaultType;
-            responseMessage.FaultPercentage = original.FaultPercentage;
-
-            // Headers
-            var newHeaders = new Dictionary<string, WireMockList<string>>();
-            foreach (var header in original.Headers)
-            {
-                var headerKey = handlebarsContext.ParseAndRender(header.Key, model);
-                var templateHeaderValues = header.Value
-                    .Select(text => handlebarsContext.ParseAndRender(text, model))
-                    .ToArray();
-
-                newHeaders.Add(headerKey, new WireMockList<string>(templateHeaderValues));
-            }
-
-            responseMessage.Headers = newHeaders;
-
-            switch (original.StatusCode)
-            {
-                case int statusCodeAsInteger:
-                    responseMessage.StatusCode = statusCodeAsInteger;
-                    break;
-
-                case string statusCodeAsString:
-                    responseMessage.StatusCode = handlebarsContext.ParseAndRender(statusCodeAsString, model);
-                    break;
-            }
-
-            return responseMessage;
-        }
-
-        private static void TransformBodyAsJson(ITransformerContext handlebarsContext, object model, ResponseMessage original, ResponseMessage responseMessage)
-        {
-            JToken jToken;
-            switch (original.BodyData.BodyAsJson)
-            {
-                case JObject bodyAsJObject:
-                    jToken = bodyAsJObject.DeepClone();
-                    WalkNode(handlebarsContext, jToken, model);
-                    break;
-
-                case Array bodyAsArray:
-                    jToken = JArray.FromObject(bodyAsArray);
-                    WalkNode(handlebarsContext, jToken, model);
-                    break;
-
-                case string bodyAsString:
-                    jToken = ReplaceSingleNode(handlebarsContext, bodyAsString, model);
-                    break;
-
-                default:
-                    jToken = JObject.FromObject(original.BodyData.BodyAsJson);
-                    WalkNode(handlebarsContext, jToken, model);
-                    break;
-            }
-
-            responseMessage.BodyData = new BodyData
-            {
-                Encoding = original.BodyData.Encoding,
-                DetectedBodyType = original.BodyData.DetectedBodyType,
-                DetectedBodyTypeFromContentType = original.BodyData.DetectedBodyTypeFromContentType,
-                BodyAsJson = jToken
-            };
-        }
-
-        private static JToken ReplaceSingleNode(ITransformerContext handlebarsContext, string stringValue, object model)
-        {
-            string transformedString = handlebarsContext.ParseAndRender(stringValue, model) as string;
-
-            if (!string.Equals(stringValue, transformedString))
-            {
-                const string property = "_";
-                JObject dummy = JObject.Parse($"{{ \"{property}\": null }}");
-                JToken node = dummy[property];
-
-                ReplaceNodeValue(node, transformedString);
-
-                return dummy[property];
-            }
-
-            return stringValue;
-        }
-
-        private static void WalkNode(ITransformerContext handlebarsContext, JToken node, object model)
-        {
-            if (node.Type == JTokenType.Object)
-            {
-                // In case of Object, loop all children. Do a ToArray() to avoid `Collection was modified` exceptions.
-                foreach (JProperty child in node.Children<JProperty>().ToArray())
-                {
-                    WalkNode(handlebarsContext, child.Value, model);
-                }
-            }
-            else if (node.Type == JTokenType.Array)
-            {
-                // In case of Array, loop all items. Do a ToArray() to avoid `Collection was modified` exceptions.
-                foreach (JToken child in node.Children().ToArray())
-                {
-                    WalkNode(handlebarsContext, child, model);
-                }
-            }
-            else if (node.Type == JTokenType.String)
-            {
-                // In case of string, try to transform the value.
-                string stringValue = node.Value<string>();
-                if (string.IsNullOrEmpty(stringValue))
-                {
-                    return;
-                }
-
-                string transformedString = handlebarsContext.ParseAndRender(stringValue, model);
-                if (!string.Equals(stringValue, transformedString))
-                {
-                    ReplaceNodeValue(node, transformedString);
-                }
-            }
-        }
-
-        private static void ReplaceNodeValue(JToken node, string stringValue)
-        {
-            if (bool.TryParse(stringValue, out bool valueAsBoolean))
-            {
-                node.Replace(valueAsBoolean);
-                return;
-            }
-
-            JToken value;
-            try
-            {
-                // Try to convert this string into a JsonObject
-                value = JToken.Parse(stringValue);
-            }
-            catch (JsonException)
-            {
-                // Ignore JsonException and just keep string value and convert to JToken
-                value = stringValue;
-            }
-
-            node.Replace(value);
-        }
-
-        private static void TransformBodyAsString(ITransformerContext handlebarsContext, object model, ResponseMessage original, ResponseMessage responseMessage)
-        {
-            responseMessage.BodyData = new BodyData
-            {
-                Encoding = original.BodyData.Encoding,
-                DetectedBodyType = original.BodyData.DetectedBodyType,
-                DetectedBodyTypeFromContentType = original.BodyData.DetectedBodyTypeFromContentType,
-                BodyAsString = handlebarsContext.ParseAndRender(original.BodyData.BodyAsString, model)
-            };
-        }
-
-        private void TransformBodyAsFile(ITransformerContext handlebarsContext, object model, ResponseMessage original, ResponseMessage responseMessage, bool useTransformerForBodyAsFile)
-        {
-            string transformedBodyAsFilename = handlebarsContext.ParseAndRender(original.BodyData.BodyAsFile, model);
-
-            if (!useTransformerForBodyAsFile)
-            {
-                responseMessage.BodyData = new BodyData
-                {
-                    DetectedBodyType = original.BodyData.DetectedBodyType,
-                    DetectedBodyTypeFromContentType = original.BodyData.DetectedBodyTypeFromContentType,
-                    BodyAsFile = transformedBodyAsFilename
-                };
-            }
-            else
-            {
-                string text = handlebarsContext.FileSystemHandler.ReadResponseBodyAsString(transformedBodyAsFilename);
-
-                responseMessage.BodyData = new BodyData
-                {
-                    DetectedBodyType = BodyType.String,
-                    DetectedBodyTypeFromContentType = original.BodyData.DetectedBodyTypeFromContentType,
-                    BodyAsString = handlebarsContext.ParseAndRender(text, model),
-                    BodyAsFile = transformedBodyAsFilename
-                };
-            }
-        }
-    }
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using JetBrains.Annotations;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
+using WireMock.Types;
+using WireMock.Util;
+
+namespace WireMock.Transformers.Handlebars
+{
+    internal class Transformer : ITransformer
+    {
+        private readonly ITransformerContextFactory _factory;
+
+        public Transformer([NotNull] ITransformerContextFactory factory)
+        {
+            _factory = factory ?? throw new ArgumentNullException(nameof(factory));
+        }
+
+        public (IBodyData BodyData, IDictionary<string, WireMockList<string>> Headers) Transform(RequestMessage originalRequestMessage, ResponseMessage originalResponseMessage, IBodyData bodyData, IDictionary<string, WireMockList<string>> headers)
+        {
+            var transformerContext = _factory.Create();
+
+            var model = new
+            {
+                request = originalRequestMessage,
+                response = originalResponseMessage
+            };
+
+            IBodyData newBodyData = null;
+            if (bodyData?.DetectedBodyType != null)
+            {
+                newBodyData = TransformBodyData(transformerContext, model, bodyData, false);
+            }
+
+            return (newBodyData, TransformHeaders(transformerContext, model, headers));
+        }
+
+        public ResponseMessage Transform(RequestMessage requestMessage, ResponseMessage original, bool useTransformerForBodyAsFile)
+        {
+            var transformerContext = _factory.Create();
+
+            var responseMessage = new ResponseMessage();
+
+            var model = new
+            {
+                request = requestMessage
+            };
+
+            if (original.BodyData?.DetectedBodyType != null)
+            {
+                responseMessage.BodyData = TransformBodyData(transformerContext, model, original.BodyData, useTransformerForBodyAsFile);
+
+                if (original.BodyData.DetectedBodyType == BodyType.String)
+                {
+                    responseMessage.BodyOriginal = original.BodyData.BodyAsString;
+                }
+            }
+
+            responseMessage.FaultType = original.FaultType;
+            responseMessage.FaultPercentage = original.FaultPercentage;
+
+            responseMessage.Headers = TransformHeaders(transformerContext, model, original.Headers);
+
+            switch (original.StatusCode)
+            {
+                case int statusCodeAsInteger:
+                    responseMessage.StatusCode = statusCodeAsInteger;
+                    break;
+
+                case string statusCodeAsString:
+                    responseMessage.StatusCode = transformerContext.ParseAndRender(statusCodeAsString, model);
+                    break;
+            }
+
+            return responseMessage;
+        }
+
+        private static IBodyData TransformBodyData(ITransformerContext transformerContext, object model, IBodyData original, bool useTransformerForBodyAsFile)
+        {
+            switch (original?.DetectedBodyType)
+            {
+                case BodyType.Json:
+                    return TransformBodyAsJson(transformerContext, model, original);
+
+                case BodyType.File:
+                    return TransformBodyAsFile(transformerContext, model, original, useTransformerForBodyAsFile);
+
+                case BodyType.String:
+                    return TransformBodyAsString(transformerContext, model, original);
+
+                default:
+                    return null;
+            }
+        }
+
+        private static IDictionary<string, WireMockList<string>> TransformHeaders(ITransformerContext transformerContext, object model, IDictionary<string, WireMockList<string>> original)
+        {
+            if (original == null)
+            {
+                return new Dictionary<string, WireMockList<string>>();
+            }
+
+            var newHeaders = new Dictionary<string, WireMockList<string>>();
+            foreach (var header in original)
+            {
+                var headerKey = transformerContext.ParseAndRender(header.Key, model);
+                var templateHeaderValues = header.Value.Select(text => transformerContext.ParseAndRender(text, model)).ToArray();
+
+                newHeaders.Add(headerKey, new WireMockList<string>(templateHeaderValues));
+            }
+
+            return newHeaders;
+        }
+
+        private static IBodyData TransformBodyAsJson(ITransformerContext handlebarsContext, object model, IBodyData original)
+        {
+            JToken jToken;
+            switch (original.BodyAsJson)
+            {
+                case JObject bodyAsJObject:
+                    jToken = bodyAsJObject.DeepClone();
+                    WalkNode(handlebarsContext, jToken, model);
+                    break;
+
+                case Array bodyAsArray:
+                    jToken = JArray.FromObject(bodyAsArray);
+                    WalkNode(handlebarsContext, jToken, model);
+                    break;
+
+                case string bodyAsString:
+                    jToken = ReplaceSingleNode(handlebarsContext, bodyAsString, model);
+                    break;
+
+                default:
+                    jToken = JObject.FromObject(original.BodyAsJson);
+                    WalkNode(handlebarsContext, jToken, model);
+                    break;
+            }
+
+            return new BodyData
+            {
+                Encoding = original.Encoding,
+                DetectedBodyType = original.DetectedBodyType,
+                DetectedBodyTypeFromContentType = original.DetectedBodyTypeFromContentType,
+                BodyAsJson = jToken
+            };
+        }
+
+        private static JToken ReplaceSingleNode(ITransformerContext handlebarsContext, string stringValue, object model)
+        {
+            string transformedString = handlebarsContext.ParseAndRender(stringValue, model);
+
+            if (!string.Equals(stringValue, transformedString))
+            {
+                const string property = "_";
+                JObject dummy = JObject.Parse($"{{ \"{property}\": null }}");
+                JToken node = dummy[property];
+
+                ReplaceNodeValue(node, transformedString);
+
+                return dummy[property];
+            }
+
+            return stringValue;
+        }
+
+        private static void WalkNode(ITransformerContext handlebarsContext, JToken node, object model)
+        {
+            if (node.Type == JTokenType.Object)
+            {
+                // In case of Object, loop all children. Do a ToArray() to avoid `Collection was modified` exceptions.
+                foreach (JProperty child in node.Children<JProperty>().ToArray())
+                {
+                    WalkNode(handlebarsContext, child.Value, model);
+                }
+            }
+            else if (node.Type == JTokenType.Array)
+            {
+                // In case of Array, loop all items. Do a ToArray() to avoid `Collection was modified` exceptions.
+                foreach (JToken child in node.Children().ToArray())
+                {
+                    WalkNode(handlebarsContext, child, model);
+                }
+            }
+            else if (node.Type == JTokenType.String)
+            {
+                // In case of string, try to transform the value.
+                string stringValue = node.Value<string>();
+                if (string.IsNullOrEmpty(stringValue))
+                {
+                    return;
+                }
+
+                string transformedString = handlebarsContext.ParseAndRender(stringValue, model);
+                if (!string.Equals(stringValue, transformedString))
+                {
+                    ReplaceNodeValue(node, transformedString);
+                }
+            }
+        }
+
+        private static void ReplaceNodeValue(JToken node, string stringValue)
+        {
+            if (bool.TryParse(stringValue, out bool valueAsBoolean))
+            {
+                node.Replace(valueAsBoolean);
+                return;
+            }
+
+            JToken value;
+            try
+            {
+                // Try to convert this string into a JsonObject
+                value = JToken.Parse(stringValue);
+            }
+            catch (JsonException)
+            {
+                // Ignore JsonException and just keep string value and convert to JToken
+                value = stringValue;
+            }
+
+            node.Replace(value);
+        }
+
+        private static IBodyData TransformBodyAsString(ITransformerContext handlebarsContext, object model, IBodyData original)
+        {
+            return new BodyData
+            {
+                Encoding = original.Encoding,
+                DetectedBodyType = original.DetectedBodyType,
+                DetectedBodyTypeFromContentType = original.DetectedBodyTypeFromContentType,
+                BodyAsString = handlebarsContext.ParseAndRender(original.BodyAsString, model)
+            };
+        }
+
+        private static IBodyData TransformBodyAsFile(ITransformerContext handlebarsContext, object model, IBodyData original, bool useTransformerForBodyAsFile)
+        {
+            string transformedBodyAsFilename = handlebarsContext.ParseAndRender(original.BodyAsFile, model);
+
+            if (!useTransformerForBodyAsFile)
+            {
+                return new BodyData
+                {
+                    DetectedBodyType = original.DetectedBodyType,
+                    DetectedBodyTypeFromContentType = original.DetectedBodyTypeFromContentType,
+                    BodyAsFile = transformedBodyAsFilename
+                };
+            }
+            else
+            {
+                string text = handlebarsContext.FileSystemHandler.ReadResponseBodyAsString(transformedBodyAsFilename);
+
+                return new BodyData
+                {
+                    DetectedBodyType = BodyType.String,
+                    DetectedBodyTypeFromContentType = original.DetectedBodyTypeFromContentType,
+                    BodyAsString = handlebarsContext.ParseAndRender(text, model),
+                    BodyAsFile = transformedBodyAsFilename
+                };
+            }
+        }
+    }
 }

test/WireMock.Net.Tests/Serialization/MappingConverterTests.cs

@@ -1,9 +1,13 @@
 using System;
+using System.Collections.Generic;
 using FluentAssertions;
+using WireMock.Models;
 using WireMock.RequestBuilders;
 using WireMock.ResponseBuilders;
 using WireMock.Serialization;
 using WireMock.Settings;
+using WireMock.Types;
+using WireMock.Util;
 using Xunit;
 
 namespace WireMock.Net.Tests.Serialization
@@ -25,7 +29,26 @@ namespace WireMock.Net.Tests.Serialization
             // Assign
             var request = Request.Create();
             var response = Response.Create();
-            var mapping = new Mapping(Guid.NewGuid(), "", null, _settings, request, response, 0, null, null, null, null);
+            var webhook = new Webhook
+            {
+                Request = new WebhookRequest
+                {
+                    Url = "https://test.com",
+                    Headers = new Dictionary<string, WireMockList<string>>
+                    {
+                        { "Single", new WireMockList<string>("x") },
+                        { "Multi", new WireMockList<string>("a", "b") }
+                    },
+                    Method = "post",
+                    BodyData = new BodyData
+                    {
+                        BodyAsString = "b",
+                        DetectedBodyType = BodyType.String,
+                        DetectedBodyTypeFromContentType = BodyType.String
+                    }
+                }
+            };
+            var mapping = new Mapping(Guid.NewGuid(), "", null, _settings, request, response, 0, null, null, null, null, webhook);
 
             // Act
             var model = _sut.ToMappingModel(mapping);
@@ -33,9 +56,16 @@ namespace WireMock.Net.Tests.Serialization
             // Assert
             model.Should().NotBeNull();
             model.Priority.Should().BeNull();
+
             model.Response.BodyAsJsonIndented.Should().BeNull();
             model.Response.UseTransformer.Should().BeNull();
             model.Response.Headers.Should().BeNull();
+
+            model.Webhook.Request.Method.Should().Be("post");
+            model.Webhook.Request.Url.Should().Be("https://test.com");
+            model.Webhook.Request.Headers.Should().HaveCount(2);
+            model.Webhook.Request.Body.Should().Be("b");
+            model.Webhook.Request.BodyAsJson.Should().BeNull();
         }
 
         [Fact]
@@ -44,7 +74,7 @@ namespace WireMock.Net.Tests.Serialization
             // Assign
             var request = Request.Create();
             var response = Response.Create().WithBodyAsJson(new { x = "x" }).WithTransformer();
-            var mapping = new Mapping(Guid.NewGuid(), "", null, _settings, request, response, 42, null, null, null, null);
+            var mapping = new Mapping(Guid.NewGuid(), "", null, _settings, request, response, 42, null, null, null, null, null);
 
             // Act
             var model = _sut.ToMappingModel(mapping);

test/WireMock.Net.Tests/Serialization/WebhookMapperTests.cs

@@ -0,0 +1,101 @@
+using System.Collections.Generic;
+using FluentAssertions;
+using WireMock.Admin.Mappings;
+using WireMock.Serialization;
+using WireMock.Types;
+using Xunit;
+
+namespace WireMock.Net.Tests.Serialization
+{
+    public class WebhookMapperTests
+    {
+        [Fact]
+        public void WebhookMapper_Map_Model_BodyAsString_And_UseTransformerIsFalse()
+        {
+            // Assign
+            var model = new WebhookModel
+            {
+                Request = new WebhookRequestModel
+                {
+                    Url = "https://localhost",
+                    Method = "get",
+                    Headers = new Dictionary<string, string>
+                    {
+                        { "x", "y" }
+                    },
+                    Body = "test",
+                    UseTransformer = false
+                }
+            };
+
+            var result = WebhookMapper.Map(model);
+
+            result.Request.Url.Should().Be("https://localhost");
+            result.Request.Method.Should().Be("get");
+            result.Request.Headers.Should().HaveCount(1);
+            result.Request.BodyData.BodyAsJson.Should().BeNull();
+            result.Request.BodyData.BodyAsString.Should().Be("test");
+            result.Request.BodyData.DetectedBodyType.Should().Be(BodyType.String);
+            result.Request.UseTransformer.Should().BeNull();
+        }
+
+        [Fact]
+        public void WebhookMapper_Map_Model_BodyAsString_And_UseTransformerIsTrue()
+        {
+            // Assign
+            var model = new WebhookModel
+            {
+                Request = new WebhookRequestModel
+                {
+                    Url = "https://localhost",
+                    Method = "get",
+                    Headers = new Dictionary<string, string>
+                    {
+                        { "x", "y" }
+                    },
+                    Body = "test",
+                    UseTransformer = true
+                }
+            };
+
+            var result = WebhookMapper.Map(model);
+
+            result.Request.Url.Should().Be("https://localhost");
+            result.Request.Method.Should().Be("get");
+            result.Request.Headers.Should().HaveCount(1);
+            result.Request.BodyData.BodyAsJson.Should().BeNull();
+            result.Request.BodyData.BodyAsString.Should().Be("test");
+            result.Request.BodyData.DetectedBodyType.Should().Be(BodyType.String);
+            result.Request.UseTransformer.Should().BeTrue();
+            result.Request.TransformerType.Should().Be(TransformerType.Handlebars);
+        }
+
+        [Fact]
+        public void WebhookMapper_Map_Model_BodyAsJson()
+        {
+            // Assign
+            var model = new WebhookModel
+            {
+                Request = new WebhookRequestModel
+                {
+                    Url = "https://localhost",
+                    Method = "get",
+                    Headers = new Dictionary<string, string>
+                    {
+                        { "x", "y" }
+                    },
+                    BodyAsJson = new { n = 12345 }
+                }
+            };
+
+            var result = WebhookMapper.Map(model);
+
+            result.Request.Url.Should().Be("https://localhost");
+            result.Request.Method.Should().Be("get");
+            result.Request.Headers.Should().HaveCount(1);
+            result.Request.BodyData.BodyAsString.Should().BeNull();
+            result.Request.BodyData.BodyAsJson.Should().NotBeNull();
+            result.Request.BodyData.DetectedBodyType.Should().Be(BodyType.Json);
+        }
+    }
+}

test/WireMock.Net.Tests/WireMockServer.WebhookTests.cs

@@ -0,0 +1,133 @@
+using System;
+using System.Linq;
+using System.Net;
+using System.Net.Http;
+using System.Threading.Tasks;
+using FluentAssertions;
+using WireMock.Models;
+using WireMock.RequestBuilders;
+using WireMock.ResponseBuilders;
+using WireMock.Server;
+using WireMock.Types;
+using WireMock.Util;
+using Xunit;
+
+namespace WireMock.Net.Tests
+{
+    public class WireMockServerWebhookTests
+    {
+        [Fact]
+        public async Task WireMockServer_WithWebhook_Should_Send_Message_To_Webhook()
+        {
+            // Assign
+            var serverReceivingTheWebhook = WireMockServer.Start();
+            serverReceivingTheWebhook.Given(Request.Create().UsingPost()).RespondWith(Response.Create().WithStatusCode(200));
+
+            // Act
+            var server = WireMockServer.Start();
+            server.Given(Request.Create().UsingPost())
+                .WithWebhook(new Webhook
+                {
+                    Request = new WebhookRequest
+                    {
+                        Url = serverReceivingTheWebhook.Urls[0],
+                        Method = "post",
+                        BodyData = new BodyData
+                        {
+                            BodyAsString = "abc",
+                            DetectedBodyType = BodyType.String,
+                            DetectedBodyTypeFromContentType = BodyType.String
+                        }
+                    }
+                })
+                .RespondWith(Response.Create().WithBody("a-response"));
+
+            var request = new HttpRequestMessage
+            {
+                Method = HttpMethod.Post,
+                RequestUri = new Uri($"{server.Urls[0]}/TST"),
+                Content = new StringContent("test")
+            };
+
+            // Assert
+            var response = await new HttpClient().SendAsync(request);
+            string content = await response.Content.ReadAsStringAsync();
+
+            response.StatusCode.Should().Be(HttpStatusCode.OK);
+            content.Should().Be("a-response");
+
+            serverReceivingTheWebhook.LogEntries.Should().HaveCount(1);
+
+            server.Dispose();
+            serverReceivingTheWebhook.Dispose();
+        }
+
+        [Fact]
+        public async Task WireMockServer_WithWebhookArgs_Should_Send_StringMessage_To_Webhook()
+        {
+            // Assign
+            var serverReceivingTheWebhook = WireMockServer.Start();
+            serverReceivingTheWebhook.Given(Request.Create().UsingPost()).RespondWith(Response.Create().WithStatusCode(200));
+
+            // Act
+            var server = WireMockServer.Start();
+            server.Given(Request.Create().UsingPost())
+                .WithWebhook(serverReceivingTheWebhook.Urls[0], "post", null, "OK !", true, TransformerType.Handlebars)
+                .RespondWith(Response.Create().WithBody("a-response"));
+
+            var request = new HttpRequestMessage
+            {
+                Method = HttpMethod.Post,
+                RequestUri = new Uri($"{server.Urls[0]}/TST"),
+                Content = new StringContent("test")
+            };
+
+            // Assert
+            var response = await new HttpClient().SendAsync(request);
+            string content = await response.Content.ReadAsStringAsync();
+
+            response.StatusCode.Should().Be(HttpStatusCode.OK);
+            content.Should().Be("a-response");
+
+            serverReceivingTheWebhook.LogEntries.Should().HaveCount(1);
+            serverReceivingTheWebhook.LogEntries.First().RequestMessage.Body.Should().Be("OK !");
+
+            server.Dispose();
+            serverReceivingTheWebhook.Dispose();
+        }
+
+        [Fact]
+        public async Task WireMockServer_WithWebhookArgs_Should_Send_JsonMessage_To_Webhook()
+        {
+            // Assign
+            var serverReceivingTheWebhook = WireMockServer.Start();
+            serverReceivingTheWebhook.Given(Request.Create().UsingPost()).RespondWith(Response.Create().WithStatusCode(200));
+
+            // Act
+            var server = WireMockServer.Start();
+            server.Given(Request.Create().UsingPost())
+                .WithWebhook(serverReceivingTheWebhook.Urls[0], "post", null, new { Status = "OK" }, true, TransformerType.Handlebars)
+                .RespondWith(Response.Create().WithBody("a-response"));
+
+            var request = new HttpRequestMessage
+            {
+                Method = HttpMethod.Post,
+                RequestUri = new Uri($"{server.Urls[0]}/TST"),
+                Content = new StringContent("test")
+            };
+
+            // Assert
+            var response = await new HttpClient().SendAsync(request);
+            string content = await response.Content.ReadAsStringAsync();
+
+            response.StatusCode.Should().Be(HttpStatusCode.OK);
+            content.Should().Be("a-response");
+
+            serverReceivingTheWebhook.LogEntries.Should().HaveCount(1);
+            serverReceivingTheWebhook.LogEntries.First().RequestMessage.Body.Should().Be("{\"Status\":\"OK\"}");
+
+            server.Dispose();
+            serverReceivingTheWebhook.Dispose();
+        }
+    }
+}