Support adding custom plaintext headers to downstream requests (#314)

docs/features/headerstransformation.rst

@@ -1,15 +1,31 @@
 Headers Transformation
-=====================
+======================
 
 Ocelot allows the user to transform headers pre and post downstream request. At the moment Ocelot only supports find and replace. This feature was requested `GitHub #190 <https://github.com/TomPallister/Ocelot/issues/190>`_ and I decided that it was going to be useful in various ways.
 
+Add to Request
+^^^^^^^^^^^^^^
+
+This feature was requestes in `GitHub #313 <https://github.com/ThreeMammals/Ocelot/issues/313>`_.
+
+If you want to add a header to your upstream request please add the following to a ReRoute in your configuration.json:
+
+.. code-block:: json
+
+    "UpstreamHeaderTransform": {
+        "Uncle": "Bob"
+    }
+
+In the example above a header with the key Uncle and value Bob would be send to to the upstream service.
+
+Placeholders are supported too (see below).
+
 Add to Response
 ^^^^^^^^^^^^^^^
 
-This feature was requested in `GitHub #280 <https://github.com/TomPallister/Ocelot/issues/280>`_. I have only implemented
-for responses but could add for requests in the future.
+This feature was requested in `GitHub #280 <https://github.com/TomPallister/Ocelot/issues/280>`_.
 
-If you want to add a header to your downstream response please add the following to a ReRoute in configuration.json..
+If you want to add a header to your downstream response please add the following to a ReRoute in configuration.json.
 
 .. code-block:: json
 
@@ -50,7 +66,7 @@ Add the following to a ReRoute in configuration.json in order to replace http://
     },
 
 Post Downstream Request
-^^^^^^^^^^^^^^^^^^^^^^
+^^^^^^^^^^^^^^^^^^^^^^^
 
 Add the following to a ReRoute in configuration.json in order to replace http://www.bbc.co.uk/ with http://ocelot.com/. This transformation will take place after Ocelot has received the response from the downstream service.
 

src/Ocelot/Configuration/Builder/DownstreamReRouteBuilder.cs

@@ -39,12 +39,14 @@ public class DownstreamReRouteBuilder
         private string _key;
         private List<string> _delegatingHandlers;
         private List<AddHeader> _addHeadersToDownstream;
+        private List<AddHeader> _addHeadersToUpstream;
 
         public DownstreamReRouteBuilder()
         {
             _downstreamAddresses = new List<DownstreamHostAndPort>();
             _delegatingHandlers = new List<string>();
             _addHeadersToDownstream = new List<AddHeader>();
+            _addHeadersToUpstream = new List<AddHeader>();
         }
 
         public DownstreamReRouteBuilder WithDownstreamAddresses(List<DownstreamHostAndPort> downstreamAddresses)
@@ -233,6 +235,12 @@ public DownstreamReRouteBuilder WithAddHeadersToDownstream(List<AddHeader> addHe
             return this;
         }
 
+        public DownstreamReRouteBuilder WithAddHeadersToUpstream(List<AddHeader> addHeadersToUpstream)
+        {
+            _addHeadersToUpstream = addHeadersToUpstream;
+            return this;
+        }
+
         public DownstreamReRoute Build()
         {
             return new DownstreamReRoute(
@@ -263,7 +271,8 @@ public DownstreamReRoute Build()
                 new PathTemplate(_downstreamPathTemplate),
                 _reRouteKey,
                 _delegatingHandlers,
-                _addHeadersToDownstream);
+                _addHeadersToDownstream,
+                _addHeadersToUpstream);
         }
     }
 }

src/Ocelot/Configuration/Creator/FileOcelotConfigurationCreator.cs

@@ -214,7 +214,8 @@ private DownstreamReRoute SetUpDownstreamReRoute(FileReRoute fileReRoute, FileGl
                 .WithDownstreamHeaderFindAndReplace(hAndRs.Downstream)
                 .WithUpstreamHost(fileReRoute.UpstreamHost)
                 .WithDelegatingHandlers(fileReRoute.DelegatingHandlers)
-                .WithAddHeadersToDownstream(hAndRs.AddHeadersToDownstream)
+                .WithAddHeadersToDownstream(hAndRs.AddHeadersToDownstream)  
+                .WithAddHeadersToUpstream(hAndRs.AddHeadersToUpstream)
                 .Build();
 
             return reRoute;

src/Ocelot/Configuration/Creator/HeaderFindAndReplaceCreator.cs

@@ -22,23 +22,31 @@ public HeaderFindAndReplaceCreator(IPlaceholders placeholders, IOcelotLoggerFact
         public HeaderTransformations Create(FileReRoute fileReRoute)
         {
             var upstream = new List<HeaderFindAndReplace>();
+            var addHeadersToUpstream = new List<AddHeader>();
 
             foreach(var input in fileReRoute.UpstreamHeaderTransform)
             {
-                var hAndr = Map(input);
-                if(!hAndr.IsError)
+                if (input.Value.Contains(","))
                 {
-                    upstream.Add(hAndr.Data);
+                    var hAndr = Map(input);
+                    if (!hAndr.IsError)
+                    {
+                        upstream.Add(hAndr.Data);
+                    }
+                    else
+                    {
+                        _logger.LogWarning($"Unable to add UpstreamHeaderTransform {input.Key}: {input.Value}");
+                    }
                 }
                 else
                 {
-                    _logger.LogWarning($"Unable to add UpstreamHeaderTransform {input.Key}: {input.Value}");
+                    addHeadersToUpstream.Add(new AddHeader(input.Key, input.Value));
                 }
             }
 
             var downstream = new List<HeaderFindAndReplace>();
             var addHeadersToDownstream = new List<AddHeader>();
-
+            
             foreach(var input in fileReRoute.DownstreamHeaderTransform)
             {
                 if(input.Value.Contains(","))
@@ -59,7 +67,7 @@ public HeaderTransformations Create(FileReRoute fileReRoute)
                 }
             }
 
-            return new HeaderTransformations(upstream, downstream, addHeadersToDownstream);
+            return new HeaderTransformations(upstream, downstream, addHeadersToDownstream, addHeadersToUpstream);
         }
 
         private Response<HeaderFindAndReplace> Map(KeyValuePair<string,string> input)

src/Ocelot/Configuration/Creator/HeaderTransformations.cs

@@ -7,9 +7,11 @@ public class HeaderTransformations
         public HeaderTransformations(
             List<HeaderFindAndReplace> upstream, 
             List<HeaderFindAndReplace> downstream,
-            List<AddHeader> addHeader)
+            List<AddHeader> addHeaderToDownstream,
+            List<AddHeader> addHeaderToUpstream)
         {
-            AddHeadersToDownstream = addHeader;
+            AddHeadersToDownstream = addHeaderToDownstream;
+            AddHeadersToUpstream = addHeaderToUpstream;
             Upstream = upstream;
             Downstream = downstream;
         }
@@ -19,5 +21,6 @@ public HeaderTransformations(
         public List<HeaderFindAndReplace> Downstream { get; }
 
         public List<AddHeader> AddHeadersToDownstream { get; }
+        public List<AddHeader> AddHeadersToUpstream { get; }
     }
 }

src/Ocelot/Configuration/DownstreamReRoute.cs

@@ -34,7 +34,8 @@ public DownstreamReRoute(
             PathTemplate downstreamPathTemplate, 
             string reRouteKey,
             List<string> delegatingHandlers,
-            List<AddHeader> addHeadersToDownstream)
+            List<AddHeader> addHeadersToDownstream,
+            List<AddHeader> addHeadersToUpstream)
         {
             AddHeadersToDownstream = addHeadersToDownstream;
             DelegatingHandlers = delegatingHandlers;
@@ -64,6 +65,7 @@ public DownstreamReRoute(
             AuthenticationOptions = authenticationOptions;
             DownstreamPathTemplate = downstreamPathTemplate;
             ReRouteKey = reRouteKey;
+            AddHeadersToUpstream = addHeadersToUpstream;
         }
 
         public string Key { get; private set; }
@@ -94,5 +96,6 @@ public DownstreamReRoute(
         public string ReRouteKey { get; private set; }
         public List<string> DelegatingHandlers {get;private set;}
         public List<AddHeader> AddHeadersToDownstream {get;private set;}
+        public List<AddHeader> AddHeadersToUpstream { get; private set; }
     }
 }

src/Ocelot/Headers/AddHeadersToRequest.cs

@@ -4,6 +4,7 @@
 using Ocelot.Infrastructure.Claims.Parser;
 using Ocelot.Responses;
 using System.Net.Http;
+using Microsoft.AspNetCore.Http;
 using Ocelot.Configuration.Creator;
 using Ocelot.Request.Middleware;
 
@@ -41,5 +42,19 @@ public Response SetHeadersOnDownstreamRequest(List<ClaimToThing> claimsToThings,
 
             return new OkResponse();
         }
+
+        public void SetHeadersOnDownstreamRequest(IEnumerable<AddHeader> headers, HttpContext context)
+        {
+            var requestHeader = context.Request.Headers;
+            foreach (var header in headers)
+            {
+                if (requestHeader.ContainsKey(header.Key))
+                {
+                    requestHeader.Remove(header.Key);
+                }
+
+                requestHeader.Add(header.Key, header.Value);
+            }
+        }
     }
-}
+}

src/Ocelot/Headers/IAddHeadersToRequest.cs

@@ -1,4 +1,6 @@
-namespace Ocelot.Headers
+using Microsoft.AspNetCore.Http;
+
+namespace Ocelot.Headers
 {
     using System.Collections.Generic;
     using System.Net.Http;
@@ -12,5 +14,6 @@
     public interface IAddHeadersToRequest
     {
         Response SetHeadersOnDownstreamRequest(List<ClaimToThing> claimsToThings, IEnumerable<System.Security.Claims.Claim> claims, DownstreamRequest downstreamRequest);
+        void SetHeadersOnDownstreamRequest(IEnumerable<AddHeader> headers, HttpContext context);
     }
 }

src/Ocelot/Headers/Middleware/HttpHeadersTransformationMiddleware.cs

@@ -9,16 +9,19 @@ public class HttpHeadersTransformationMiddleware : OcelotMiddleware
         private readonly OcelotRequestDelegate _next;
         private readonly IHttpContextRequestHeaderReplacer _preReplacer;
         private readonly IHttpResponseHeaderReplacer _postReplacer;
-        private readonly IAddHeadersToResponse _addHeaders;
+        private readonly IAddHeadersToResponse _addHeadersToResponse;
+        private readonly IAddHeadersToRequest _addHeadersToRequest;
 
         public HttpHeadersTransformationMiddleware(OcelotRequestDelegate next,
             IOcelotLoggerFactory loggerFactory,
             IHttpContextRequestHeaderReplacer preReplacer,
             IHttpResponseHeaderReplacer postReplacer,
-            IAddHeadersToResponse addHeaders) 
+            IAddHeadersToResponse addHeadersToResponse,
+            IAddHeadersToRequest addHeadersToRequest) 
                 :base(loggerFactory.CreateLogger<HttpHeadersTransformationMiddleware>())
         {
-            _addHeaders = addHeaders;
+            _addHeadersToResponse = addHeadersToResponse;
+            _addHeadersToRequest = addHeadersToRequest;
             _next = next;
             _postReplacer = postReplacer;
             _preReplacer = preReplacer;
@@ -31,13 +34,15 @@ public async Task Invoke(DownstreamContext context)
             //todo - this should be on httprequestmessage not httpcontext?
             _preReplacer.Replace(context.HttpContext, preFAndRs);
 
+            _addHeadersToRequest.SetHeadersOnDownstreamRequest(context.DownstreamReRoute.AddHeadersToUpstream, context.HttpContext);
+
             await _next.Invoke(context);
 
             var postFAndRs = context.DownstreamReRoute.DownstreamHeadersFindAndReplace;
 
             _postReplacer.Replace(context.DownstreamResponse, postFAndRs, context.DownstreamRequest);
 
-            _addHeaders.Add(context.DownstreamReRoute.AddHeadersToDownstream, context.DownstreamResponse);
+            _addHeadersToResponse.Add(context.DownstreamReRoute.AddHeadersToDownstream, context.DownstreamResponse);
         }
     }
 }

test/Ocelot.UnitTests/Configuration/FileConfigurationCreatorTests.cs

@@ -829,6 +829,7 @@ private void ThenTheReRoutesAre(List<ReRoute> expectedReRoutes)
                 result.DownstreamReRoute[0].RequestIdKey.ShouldBe(expected.DownstreamReRoute[0].RequestIdKey);   
                 result.DownstreamReRoute[0].DelegatingHandlers.ShouldBe(expected.DownstreamReRoute[0].DelegatingHandlers);      
                 result.DownstreamReRoute[0].AddHeadersToDownstream.ShouldBe(expected.DownstreamReRoute[0].AddHeadersToDownstream);           
+                result.DownstreamReRoute[0].AddHeadersToUpstream.ShouldBe(expected.DownstreamReRoute[0].AddHeadersToUpstream, "AddHeadersToUpstream should be set");
             }
         }
 
@@ -911,7 +912,7 @@ private void ThenTheHeaderFindAndReplaceCreatorIsCalledCorrectly()
 
         private void GivenTheHeaderFindAndReplaceCreatorReturns()
         {
-            _headerFindAndReplaceCreator.Setup(x => x.Create(It.IsAny<FileReRoute>())).Returns(new HeaderTransformations(new List<HeaderFindAndReplace>(), new List<HeaderFindAndReplace>(), new List<AddHeader>()));
+            _headerFindAndReplaceCreator.Setup(x => x.Create(It.IsAny<FileReRoute>())).Returns(new HeaderTransformations(new List<HeaderFindAndReplace>(), new List<HeaderFindAndReplace>(), new List<AddHeader>(), new List<AddHeader>()));
         }
 
         private void GivenTheFollowingIsReturned(ServiceProviderConfiguration serviceProviderConfiguration)

test/Ocelot.UnitTests/Configuration/HeaderFindAndReplaceCreatorTests.cs

@@ -149,7 +149,6 @@ public void should_use_base_url_partial_placeholder()
                 .Then(x => ThenTheFollowingDownstreamIsReturned(downstream))
                 .BDDfy();
         }
-
         [Fact]
         public void should_add_trace_id_header()
         {
@@ -166,7 +165,45 @@ public void should_add_trace_id_header()
             this.Given(x => GivenTheReRoute(reRoute))
                 .And(x => GivenTheBaseUrlIs("http://ocelot.com/"))
                 .When(x => WhenICreate())
-                .Then(x => ThenTheFollowingAddHeaderIsReturned(expected))
+                .Then(x => ThenTheFollowingAddHeaderToDownstreamIsReturned(expected))
+                .BDDfy();
+        }
+
+        [Fact]
+        public void should_add_downstream_header_as_is_when_no_replacement_is_given()
+        {
+            var reRoute = new FileReRoute
+            {
+                DownstreamHeaderTransform = new Dictionary<string, string>
+                {
+                    {"X-Custom-Header", "Value"},
+                }
+            };
+
+            var expected = new AddHeader("X-Custom-Header", "Value");
+
+            this.Given(x => GivenTheReRoute(reRoute))
+                .And(x => WhenICreate())
+                .Then(x => x.ThenTheFollowingAddHeaderToDownstreamIsReturned(expected))
+                .BDDfy();
+        }
+
+        [Fact]
+        public void should_add_upstream_header_as_is_when_no_replacement_is_given()
+        {
+            var reRoute = new FileReRoute
+            {
+                UpstreamHeaderTransform = new Dictionary<string, string>
+                {
+                    {"X-Custom-Header", "Value"},
+                }
+            };
+
+            var expected = new AddHeader("X-Custom-Header", "Value");
+
+            this.Given(x => GivenTheReRoute(reRoute))
+                .And(x => WhenICreate())
+                .Then(x => x.ThenTheFollowingAddHeaderToUpstreamIsReturned(expected))
                 .BDDfy();
         }
 
@@ -180,11 +217,17 @@ private void GivenTheBaseUrlErrors()
             _placeholders.Setup(x => x.Get(It.IsAny<string>())).Returns(new ErrorResponse<string>(new AnyError()));
         }
 
-        private void ThenTheFollowingAddHeaderIsReturned(AddHeader addHeader)
+        private void ThenTheFollowingAddHeaderToDownstreamIsReturned(AddHeader addHeader)
         {
             _result.AddHeadersToDownstream[0].Key.ShouldBe(addHeader.Key);
             _result.AddHeadersToDownstream[0].Value.ShouldBe(addHeader.Value);
         }
+
+        private void ThenTheFollowingAddHeaderToUpstreamIsReturned(AddHeader addHeader)
+        {
+            _result.AddHeadersToUpstream[0].Key.ShouldBe(addHeader.Key);
+            _result.AddHeadersToUpstream[0].Value.ShouldBe(addHeader.Value);
+        }
 
         private void ThenTheFollowingDownstreamIsReturned(List<HeaderFindAndReplace> downstream)
         {