Feature/expose http handlers (#224)

* temp commit

* trying to work out how to expose the http handlers in a decent way..

* pissing about at lunch

* changed to func so you can instanciate object or new it up each time

* docs for dele handlers

* upgraded to sdk 2.1.4

* some validation for consul services

docs/features/delegatinghandlers.rst

@@ -0,0 +1,43 @@
+Delegating Handers
+==================
+
+Ocelot allows the user to add delegating handlers to the HttpClient transport. This feature was requested `GitHub #208 <https://github.com/TomPallister/Ocelot/issues/208>`_ and I decided that it was going to be useful in various ways.
+
+Usage
+^^^^^^
+
+In order to add delegating handlers to the HttpClient transport you need to do the following.
+
+.. code-block:: csharp
+
+    services.AddOcelot()
+            .AddDelegatingHandler(() => new FakeHandler())
+            .AddDelegatingHandler(() => new FakeHandler());
+
+Or for singleton like behaviour..
+
+.. code-block:: csharp
+
+    var handlerOne = new FakeHandler();
+    var handlerTwo = new FakeHandler();
+
+    services.AddOcelot()
+            .AddDelegatingHandler(() => handlerOne)
+            .AddDelegatingHandler(() => handlerTwo);
+
+You can have as many DelegatingHandlers as you want and they are run in a first in first out order. If you are using Ocelot's QoS functionality then that will always be run after your last delegating handler.
+
+In order to create a class that can be used a delegating handler it must look as follows
+
+.. code-block:: csharp
+
+    public class FakeHandler : DelegatingHandler
+    {
+        protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
+        {
+            //do stuff and optionally call the base handler..
+            return await base.SendAsync(request, cancellationToken);
+        }
+    }
+
+Hopefully other people will find this feature useful!

docs/index.rst

@@ -33,6 +33,8 @@ Thanks for taking a look at the Ocelot documentation. Please use the left hand n
    features/requestid
    features/middlewareinjection
    features/loadbalancer
+   features/delegatinghandlers
+
 
 .. toctree::
    :maxdepth: 2

global.json

@@ -1,6 +1,6 @@
 {
   "projects": [ "src", "test" ],
   "sdk": {
-    "version": "2.0.2"
+    "version": "2.1.4"
   }
 }

src/Ocelot/DependencyInjection/IOcelotAdministrationBuilder.cs

@@ -0,0 +1,7 @@
+namespace Ocelot.DependencyInjection
+{
+    public interface IOcelotAdministrationBuilder
+    {
+        IOcelotAdministrationBuilder AddRafty();
+    }
+}

src/Ocelot/DependencyInjection/IOcelotBuilder.cs

@@ -1,6 +1,7 @@
 using Butterfly.Client.AspNetCore;
 using CacheManager.Core;
 using System;
+using System.Net.Http;
 
 namespace Ocelot.DependencyInjection
 {
@@ -10,5 +11,6 @@ public interface IOcelotBuilder
         IOcelotBuilder AddCacheManager(Action<ConfigurationBuilderCachePart> settings);
         IOcelotBuilder AddOpenTracing(Action<ButterflyOptions> settings);      
         IOcelotAdministrationBuilder AddAdministration(string path, string secret);
+        IOcelotBuilder AddDelegatingHandler(Func<DelegatingHandler> delegatingHandler);
     }
 }

src/Ocelot/DependencyInjection/OcelotAdministrationBuilder.cs

@@ -0,0 +1,34 @@
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Ocelot.Raft;
+using Rafty.Concensus;
+using Rafty.FiniteStateMachine;
+using Rafty.Infrastructure;
+using Rafty.Log;
+
+namespace Ocelot.DependencyInjection
+{
+    public class OcelotAdministrationBuilder : IOcelotAdministrationBuilder
+    {
+        private readonly IServiceCollection _services;
+        private readonly IConfiguration _configurationRoot;
+
+        public OcelotAdministrationBuilder(IServiceCollection services, IConfiguration configurationRoot)
+        {
+            _configurationRoot = configurationRoot;
+            _services = services;    
+        }
+
+        public IOcelotAdministrationBuilder AddRafty()
+        {
+            var settings = new InMemorySettings(4000, 5000, 100, 5000);
+            _services.AddSingleton<ILog, SqlLiteLog>();
+            _services.AddSingleton<IFiniteStateMachine, OcelotFiniteStateMachine>();
+            _services.AddSingleton<ISettings>(settings);
+            _services.AddSingleton<IPeersProvider, FilePeersProvider>();
+            _services.AddSingleton<INode, Node>();
+            _services.Configure<FilePeers>(_configurationRoot);
+            return this;
+        }
+    }
+}

src/Ocelot/DependencyInjection/OcelotBuilder.cs

@@ -1,19 +1,12 @@
-using Butterfly.Client.AspNetCore;
 using CacheManager.Core;
-using IdentityServer4.AccessTokenValidation;
 using IdentityServer4.Models;
-using Microsoft.AspNetCore.Builder;
-using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
-using Microsoft.Extensions.DependencyInjection.Extensions;
 using Ocelot.Authorisation;
 using Ocelot.Cache;
 using Ocelot.Claims;
-using Ocelot.Configuration;
 using Ocelot.Configuration.Authentication;
-using Ocelot.Configuration.Builder;
 using Ocelot.Configuration.Creator;
 using Ocelot.Configuration.File;
 using Ocelot.Configuration.Parser;
@@ -32,32 +25,36 @@
 using Ocelot.Logging;
 using Ocelot.Middleware;
 using Ocelot.QueryStrings;
-using Ocelot.Raft;
 using Ocelot.RateLimit;
 using Ocelot.Request.Builder;
 using Ocelot.Request.Mapper;
 using Ocelot.Requester;
 using Ocelot.Requester.QoS;
 using Ocelot.Responder;
 using Ocelot.ServiceDiscovery;
-using Rafty.Concensus;
-using Rafty.FiniteStateMachine;
-using Rafty.Infrastructure;
-using Rafty.Log;
 using System;
 using System.Collections.Generic;
 using System.IdentityModel.Tokens.Jwt;
-using System.Linq;
 using System.Reflection;
 using System.Security.Cryptography.X509Certificates;
+using IdentityServer4.AccessTokenValidation;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Ocelot.Configuration;
+using Ocelot.Configuration.Builder;
 using FileConfigurationProvider = Ocelot.Configuration.Provider.FileConfigurationProvider;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+using System.Linq;
+using System.Net.Http;
+using Butterfly.Client.AspNetCore;
 
 namespace Ocelot.DependencyInjection
 {
     public class OcelotBuilder : IOcelotBuilder
     {
-        private IServiceCollection _services;
-        private IConfiguration _configurationRoot;
+        private readonly IServiceCollection _services;
+        private readonly IConfiguration _configurationRoot;
+        private IDelegatingHandlerHandlerProvider _provider;
 
         public OcelotBuilder(IServiceCollection services, IConfiguration configurationRoot)
         {
@@ -122,6 +119,9 @@ public OcelotBuilder(IServiceCollection services, IConfiguration configurationRo
             _services.TryAddSingleton<IRequestMapper, RequestMapper>();
             _services.TryAddSingleton<IHttpHandlerOptionsCreator, HttpHandlerOptionsCreator>();
             _services.TryAddSingleton<IDownstreamAddressesCreator, DownstreamAddressesCreator>();
+            _services.TryAddSingleton<IDelegatingHandlerHandlerProviderFactory, DelegatingHandlerHandlerProviderFactory>();
+            _services.TryAddSingleton<IDelegatingHandlerHandlerHouse, DelegatingHandlerHandlerHouse>();
+
             // see this for why we register this as singleton http://stackoverflow.com/questions/37371264/invalidoperationexception-unable-to-resolve-service-for-type-microsoft-aspnetc
             // could maybe use a scoped data repository
             _services.TryAddSingleton<IHttpContextAccessor, HttpContextAccessor>();
@@ -142,6 +142,11 @@ public OcelotBuilder(IServiceCollection services, IConfiguration configurationRo
             _services.AddMiddlewareAnalysis();
             _services.AddWebEncoders();
             _services.AddSingleton<IAdministrationPath>(new NullAdministrationPath());
+
+            //these get picked out later and added to http request
+            _provider = new DelegatingHandlerHandlerProvider();
+            _services.TryAddSingleton<IDelegatingHandlerHandlerProvider>(_provider);
+            _services.AddTransient<ITracingHandler, NoTracingHandler>();
         }
 
         public IOcelotAdministrationBuilder AddAdministration(string path, string secret)
@@ -161,6 +166,19 @@ public IOcelotAdministrationBuilder AddAdministration(string path, string secret
             return new OcelotAdministrationBuilder(_services, _configurationRoot);
         }
 
+        public IOcelotBuilder AddDelegatingHandler(Func<DelegatingHandler> delegatingHandler)
+        {
+            _provider.Add(delegatingHandler);
+            return this;
+        }
+
+        public IOcelotBuilder AddOpenTracing(Action<ButterflyOptions> settings)
+        {
+            _services.AddTransient<ITracingHandler, OcelotHttpTracingHandler>();
+            _services.AddButterfly(settings);   
+            return this;
+        }
+
         public IOcelotBuilder AddStoreOcelotConfigurationInConsul()
         {
             var serviceDiscoveryPort = _configurationRoot.GetValue("GlobalConfiguration:ServiceDiscoveryProvider:Port", 0);
@@ -203,13 +221,6 @@ public IOcelotBuilder AddCacheManager(Action<ConfigurationBuilderCachePart> sett
             return this;
         }
 
-        public IOcelotBuilder AddOpenTracing(Action<ButterflyOptions> settings)
-        {
-            _services.AddTransient<OcelotHttpTracingHandler>();
-            _services.AddButterfly(settings);   
-            return this;
-        }
-
         private void AddIdentityServer(IIdentityServerConfiguration identityServerConfiguration, IAdministrationPath adminPath) 
         {
             _services.TryAddSingleton<IIdentityServerConfiguration>(identityServerConfiguration);
@@ -281,33 +292,4 @@ private List<Client> Client(IIdentityServerConfiguration identityServerConfigura
             };
         }
     }
-
-    public interface IOcelotAdministrationBuilder
-    {
-        IOcelotAdministrationBuilder AddRafty();
-    }
-
-    public class OcelotAdministrationBuilder : IOcelotAdministrationBuilder
-    {
-        private IServiceCollection _services;
-        private IConfiguration _configurationRoot;
-
-        public OcelotAdministrationBuilder(IServiceCollection services, IConfiguration configurationRoot)
-        {
-            _configurationRoot = configurationRoot;
-            _services = services;    
-        }
-
-        public IOcelotAdministrationBuilder AddRafty()
-        {
-            var settings = new InMemorySettings(4000, 5000, 100, 5000);
-            _services.AddSingleton<ILog, SqlLiteLog>();
-            _services.AddSingleton<IFiniteStateMachine, OcelotFiniteStateMachine>();
-            _services.AddSingleton<ISettings>(settings);
-            _services.AddSingleton<IPeersProvider, FilePeersProvider>();
-            _services.AddSingleton<INode, Node>();
-            _services.Configure<FilePeers>(_configurationRoot);
-            return this;
-        }
-    }
 }

src/Ocelot/DownstreamRouteFinder/Finder/DownstreamRouteFinder.cs

@@ -1,9 +1,6 @@
-using System;
-using System.Collections.Generic;
+using System.Collections.Generic;
 using System.Linq;
-using System.Threading.Tasks;
 using Ocelot.Configuration;
-using Ocelot.Configuration.Provider;
 using Ocelot.DownstreamRouteFinder.UrlMatcher;
 using Ocelot.Errors;
 using Ocelot.Responses;

src/Ocelot/Errors/Middleware/ExceptionHandlerMiddleware.cs

@@ -62,7 +62,7 @@ public async Task Invoke(HttpContext context)
         private async Task TrySetGlobalRequestId(HttpContext context)
         {
                 //try and get the global request id and set it for logs...
-                //shoudl this basically be immutable per request...i guess it should!
+                //should this basically be immutable per request...i guess it should!
                 //first thing is get config
                  var configuration = await _configProvider.Get(); 
 

src/Ocelot/Errors/OcelotErrorCode.cs

@@ -33,6 +33,7 @@ public enum OcelotErrorCode
         UnmappableRequestError,
         RateLimitOptionsError,
         PathTemplateDoesntStartWithForwardSlash,
-        FileValidationFailedError
+        FileValidationFailedError,
+        UnableToFindDelegatingHandlerProviderError
     }
 }

src/Ocelot/LoadBalancer/LoadBalancers/UnableToFindLoadBalancerError.cs

@@ -9,4 +9,4 @@ public UnableToFindLoadBalancerError(string message)
         {
         }
     }
-}
+}

src/Ocelot/LoadBalancer/Middleware/LoadBalancingMiddleware.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Http;
-using Ocelot.Configuration.Provider;
 using Ocelot.Infrastructure.RequestData;
 using Ocelot.LoadBalancer.LoadBalancers;
 using Ocelot.Logging;
@@ -46,11 +45,14 @@ public async Task Invoke(HttpContext context)
             }
 
             var uriBuilder = new UriBuilder(DownstreamRequest.RequestUri);
+
             uriBuilder.Host = hostAndPort.Data.DownstreamHost;
+
             if (hostAndPort.Data.DownstreamPort > 0)
             {
                 uriBuilder.Port = hostAndPort.Data.DownstreamPort;
             }
+
             DownstreamRequest.RequestUri = uriBuilder.Uri;
 
             try

src/Ocelot/Request/Builder/HttpRequestCreator.cs

@@ -13,9 +13,10 @@ public async Task<Response<Request>> Build(
             IQoSProvider qosProvider,
             bool useCookieContainer,
             bool allowAutoRedirect,
+            string reRouteKey,
             bool isTracing)
         {
-            return new OkResponse<Request>(new Request(httpRequestMessage, isQos, qosProvider, allowAutoRedirect, useCookieContainer, isTracing));
+             return new OkResponse<Request>(new Request(httpRequestMessage, isQos, qosProvider, allowAutoRedirect, useCookieContainer, reRouteKey, isTracing));
         }
     }
 }

src/Ocelot/Request/Builder/IRequestCreator.cs

@@ -14,6 +14,7 @@ Task<Response<Request>> Build(
             IQoSProvider qosProvider,
             bool useCookieContainer,
             bool allowAutoRedirect,
+            string reRouteKe,
             bool isTracing);
     }
 }

src/Ocelot/Request/Middleware/HttpRequestBuilderMiddleware.cs

@@ -47,7 +47,9 @@ public async Task Invoke(HttpContext context)
                     qosProvider.Data,
                     DownstreamRoute.ReRoute.HttpHandlerOptions.UseCookieContainer,
                     DownstreamRoute.ReRoute.HttpHandlerOptions.AllowAutoRedirect,
+                    DownstreamRoute.ReRoute.ReRouteKey,
                     DownstreamRoute.ReRoute.HttpHandlerOptions.UseTracing);
+
             if (buildResult.IsError)
             {
                 _logger.LogDebug("IRequestCreator returned an error, setting pipeline error");

src/Ocelot/Request/Request.cs

@@ -11,6 +11,7 @@ public Request(
             IQoSProvider qosProvider, 
             bool allowAutoRedirect,
             bool useCookieContainer,
+            string reRouteKey,
             bool isTracing
             )
         {
@@ -19,6 +20,7 @@ bool isTracing
             QosProvider = qosProvider;
             AllowAutoRedirect = allowAutoRedirect;
             UseCookieContainer = useCookieContainer;
+            ReRouteKey = reRouteKey;
             IsTracing = isTracing;
         }
 
@@ -28,5 +30,6 @@ bool isTracing
         public IQoSProvider QosProvider { get; private set; }
         public bool AllowAutoRedirect { get; private set; }
         public bool UseCookieContainer { get; private set; }
+        public string ReRouteKey { get; private set; }
     }
-}
+}