#451 started implementing querystring support in templates (#459)

* #451 started implementing querystring support in templates

* #451 ocelot.json back to normal and specified in docs query string wont work in upstream template

* Revert "#451 ocelot.json back to normal and specified in docs query string wont work in upstream template"

This reverts commit 563193f7b2f78bad6109484fe77f3c87de831005.

* #451 ocelot.json back to normal and specified in docs query string wont work in upstream template

docs/features/routing.rst

@@ -185,3 +185,34 @@ Dynamic Routing
 This feature was requested in `issue 340 <https://github.com/TomPallister/Ocelot/issue/340>`_. The idea is to enable dynamic routing 
 when using a service discovery provider so you don't have to provide the ReRoute config. See the docs :ref:`service-discovery` if 
 this sounds interesting to you.
+
+Query Strings
+^^^^^^^^^^^^^
+
+Ocelot allow's you to specify a querystring as part of the DownstreamPathTemplate like the example below.
+
+.. code-block:: json
+
+    {
+        "ReRoutes": [
+            {
+                "DownstreamPathTemplate": "/api/subscriptions/{subscriptionId}/updates?unitId={unitId}",
+                "UpstreamPathTemplate": "/api/units/{subscriptionId}/{unitId}/updates",
+                "UpstreamHttpMethod": [
+                    "Get"
+                ],
+                "DownstreamScheme": "http",
+                "DownstreamHostAndPorts": [
+                    {
+                        "Host": "localhost",
+                        "Port": 50110
+                    }
+                ]
+            }
+        ],
+        "GlobalConfiguration": {
+            "UseServiceDiscovery": false
+        }
+    }
+
+In this example Ocelot will use the value from the {unitId} in the upstream path template and add it to the downstream request as a query string parameter called unitId! Please note you cannot use query string parameters to match routes in the UpstreamPathTemplate.

src/Ocelot/DownstreamUrlCreator/Middleware/DownstreamUrlCreatorMiddleware.cs

@@ -28,14 +28,14 @@ namespace Ocelot.DownstreamUrlCreator.Middleware
 
         public async Task Invoke(DownstreamContext context)
         {
-            var dsPath = _replacer
+            var response = _replacer
                 .Replace(context.DownstreamReRoute.DownstreamPathTemplate, context.TemplatePlaceholderNameAndValues);
 
-            if (dsPath.IsError)
+            if (response.IsError)
             {
                 Logger.LogDebug("IDownstreamPathPlaceholderReplacer returned an error, setting pipeline error");
 
-                SetPipelineError(context, dsPath.Errors);
+                SetPipelineError(context, response.Errors);
                 return;
             }
 
@@ -43,13 +43,26 @@ namespace Ocelot.DownstreamUrlCreator.Middleware
 
             if (ServiceFabricRequest(context))
             {
-                var pathAndQuery = CreateServiceFabricUri(context, dsPath);
+                var pathAndQuery = CreateServiceFabricUri(context, response);
                 context.DownstreamRequest.AbsolutePath = pathAndQuery.path;
                 context.DownstreamRequest.Query = pathAndQuery.query;
             }
             else
             {
-                context.DownstreamRequest.AbsolutePath = dsPath.Data.Value;
+                var dsPath = response.Data;
+
+                if(ContainsQueryString(dsPath))
+                {
+                    context.DownstreamRequest.AbsolutePath = GetPath(dsPath);
+                    context.DownstreamRequest.Query = GetQueryString(dsPath);
+
+                    // todo - do we need to add anything from the request query string onto the query from the
+                    // templae?
+                }
+                else 
+                {
+                    context.DownstreamRequest.AbsolutePath = dsPath.Value;
+                }
             }
 
             Logger.LogDebug($"Downstream url is {context.DownstreamRequest}");
@@ -57,6 +70,21 @@ namespace Ocelot.DownstreamUrlCreator.Middleware
             await _next.Invoke(context);
         }
 
+        private string GetPath(DownstreamPath dsPath)
+        {
+            return dsPath.Value.Substring(0, dsPath.Value.IndexOf("?"));
+        }
+
+         private string GetQueryString(DownstreamPath dsPath)
+        {
+            return dsPath.Value.Substring(dsPath.Value.IndexOf("?"));
+        }
+
+        private bool ContainsQueryString(DownstreamPath dsPath)
+        {
+            return dsPath.Value.Contains("?");
+        }
+
         private (string path, string query) CreateServiceFabricUri(DownstreamContext context, Response<DownstreamPath> dsPath)
         {
             var query = context.DownstreamRequest.Query;           

test/Ocelot.AcceptanceTests/RoutingWithQueryStringTests.cs

@@ -0,0 +1,104 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Net;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Http;
+using Ocelot.Configuration.File;
+using Shouldly;
+using TestStack.BDDfy;
+using Xunit;
+
+namespace Ocelot.AcceptanceTests
+{
+    public class RoutingWithQueryStringTests : IDisposable
+    {
+        private IWebHost _builder;
+        private readonly Steps _steps;
+        private string _downstreamPath;
+
+        public RoutingWithQueryStringTests()
+        {
+            _steps = new Steps();
+        }
+
+        [Fact]
+        public void should_return_response_200_with_query_string_template()
+        {
+            var subscriptionId = Guid.NewGuid().ToString();
+            var unitId = Guid.NewGuid().ToString();
+
+            var configuration = new FileConfiguration
+            {
+                ReRoutes = new List<FileReRoute>
+                    {
+                        new FileReRoute
+                        {
+                            DownstreamPathTemplate = "/api/subscriptions/{subscriptionId}/updates?unitId={unitId}",
+                            DownstreamScheme = "http",
+                            DownstreamHostAndPorts = new List<FileHostAndPort>
+                            {
+                                new FileHostAndPort
+                                {
+                                    Host = "localhost",
+                                    Port = 61879,
+                                }
+                            },
+                            UpstreamPathTemplate = "/api/units/{subscriptionId}/{unitId}/updates",
+                            UpstreamHttpMethod = new List<string> { "Get" },
+                        }
+                    }
+            };
+
+            this.Given(x => x.GivenThereIsAServiceRunningOn("http://localhost:61879", $"/api/subscriptions/{subscriptionId}/updates", $"?unitId={unitId}", 200, "Hello from Laura"))
+                .And(x => _steps.GivenThereIsAConfiguration(configuration))
+                .And(x => _steps.GivenOcelotIsRunning())
+                .When(x => _steps.WhenIGetUrlOnTheApiGateway($"/api/units/{subscriptionId}/{unitId}/updates"))
+                .Then(x => _steps.ThenTheStatusCodeShouldBe(HttpStatusCode.OK))
+                .And(x => _steps.ThenTheResponseBodyShouldBe("Hello from Laura"))
+                .BDDfy();
+        }
+
+        private void GivenThereIsAServiceRunningOn(string baseUrl, string basePath, string queryString, int statusCode, string responseBody)
+        {
+            _builder = new WebHostBuilder()
+                .UseUrls(baseUrl)
+                .UseKestrel()
+                .UseContentRoot(Directory.GetCurrentDirectory())
+                .UseIISIntegration()
+                .Configure(app =>
+                {
+                    app.UsePathBase(basePath);
+                    app.Run(async context =>
+                    {   
+
+                        if(context.Request.PathBase.Value != basePath || context.Request.QueryString.Value != queryString)
+                        {
+                            context.Response.StatusCode = 404;
+                            await context.Response.WriteAsync("downstream path didnt match base path");
+                        }
+                        else
+                        {
+                            context.Response.StatusCode = statusCode;
+                            await context.Response.WriteAsync(responseBody);
+                        }
+                    });
+                })
+                .Build();
+
+            _builder.Start();
+        }
+
+        internal void ThenTheDownstreamUrlPathShouldBe(string expectedDownstreamPath)
+        {
+            _downstreamPath.ShouldBe(expectedDownstreamPath);
+        }
+
+        public void Dispose()
+        {
+            _builder?.Dispose();
+            _steps.Dispose();
+        }
+    }
+}

test/Ocelot.UnitTests/DownstreamUrlCreator/DownstreamUrlCreatorMiddlewareTests.cs

@@ -68,6 +68,7 @@
                 .And(x => x.GivenTheUrlReplacerWillReturn("/api/products/1"))
                 .When(x => x.WhenICallTheMiddleware())
                 .Then(x => x.ThenTheDownstreamRequestUriIs("https://my.url:80/api/products/1?q=123"))
+                .And(x => ThenTheQueryStringIs("?q=123"))
                 .BDDfy();
         }
 
@@ -227,5 +228,10 @@
         {
             _downstreamContext.DownstreamRequest.ToHttpRequestMessage().RequestUri.OriginalString.ShouldBe(expectedUri);
         }
+
+        private void ThenTheQueryStringIs(string queryString)
+        {
+            _downstreamContext.DownstreamRequest.Query.ShouldBe(queryString);
+        }
     }
 }