decided to stick a basic cache in for downstream route creator, can make fancy if required (#359)

src/Ocelot/DownstreamRouteFinder/Finder/DownstreamRouteCreator.cs

@@ -1,5 +1,6 @@
 namespace Ocelot.DownstreamRouteFinder.Finder
 {
+    using System.Collections.Concurrent;
     using System.Collections.Generic;
     using Configuration;
     using Configuration.Builder;
@@ -12,10 +13,12 @@
     public class DownstreamRouteCreator : IDownstreamRouteProvider
     {
         private readonly IQoSOptionsCreator _qoSOptionsCreator;
+        private readonly ConcurrentDictionary<string, OkResponse<DownstreamRoute>> _cache;
 
         public DownstreamRouteCreator(IQoSOptionsCreator qoSOptionsCreator)
         {
             _qoSOptionsCreator = qoSOptionsCreator;
+            _cache = new ConcurrentDictionary<string, OkResponse<DownstreamRoute>>();
         }
 
         public Response<DownstreamRoute> Get(string upstreamUrlPath, string upstreamHttpMethod, IInternalConfiguration configuration, string upstreamHost)
@@ -33,6 +36,11 @@
 
             var loadBalancerKey = CreateLoadBalancerKey(downstreamPathForKeys, upstreamHttpMethod, configuration.LoadBalancerOptions);
 
+            if(_cache.TryGetValue(loadBalancerKey, out var downstreamRoute))
+            {
+                return downstreamRoute;
+            }
+
             var qosOptions = _qoSOptionsCreator.Create(configuration.QoSOptions, downstreamPathForKeys, new []{ upstreamHttpMethod });
 
             var downstreamReRoute = new DownstreamReRouteBuilder()
@@ -51,7 +59,11 @@
                 .WithUpstreamHttpMethod(new List<string>(){ upstreamHttpMethod })
                 .Build();
 
-            return new OkResponse<DownstreamRoute>(new DownstreamRoute(new List<PlaceholderNameAndValue>(), reRoute));
+            downstreamRoute = new OkResponse<DownstreamRoute>(new DownstreamRoute(new List<PlaceholderNameAndValue>(), reRoute));
+
+            _cache.AddOrUpdate(loadBalancerKey, downstreamRoute, (x, y)  => downstreamRoute);
+
+            return downstreamRoute;
         }
 
         private static string RemoveQueryString(string downstreamPath)
@@ -67,12 +79,23 @@
 
         private static string GetDownstreamPath(string upstreamUrlPath)
         {
+            if(upstreamUrlPath.IndexOf('/', 1) == -1)
+            {
+                return "/";
+            }
+
             return upstreamUrlPath
                 .Substring(upstreamUrlPath.IndexOf('/', 1));
         }
 
         private static string GetServiceName(string upstreamUrlPath)
         {
+            if(upstreamUrlPath.IndexOf('/', 1) == -1)
+            {
+                return upstreamUrlPath
+                    .Substring(1);
+            }
+
             return upstreamUrlPath
                 .Substring(1, upstreamUrlPath.IndexOf('/', 1))
                 .TrimEnd('/');

test/Ocelot.UnitTests/DownstreamRouteFinder/DownstreamRouteCreatorTests.cs

@@ -6,6 +6,7 @@ using System.Net.Http;
 
 namespace Ocelot.UnitTests.DownstreamRouteFinder
 {
+    using System;
     using Moq;
     using Ocelot.Configuration.Builder;
     using Ocelot.Configuration.Creator;
@@ -26,6 +27,7 @@ namespace Ocelot.UnitTests.DownstreamRouteFinder
         private string _upstreamHttpMethod;
         private IInternalConfiguration _configuration;
         private Mock<IQoSOptionsCreator> _qosOptionsCreator;
+        private Response<DownstreamRoute> _resultTwo;
 
         public DownstreamRouteCreatorTests()
         {
@@ -50,6 +52,32 @@ namespace Ocelot.UnitTests.DownstreamRouteFinder
                 .BDDfy();
         }
 
+        [Fact]
+        public void should_cache_downstream_route()
+        {
+            var configuration = new InternalConfiguration(null, "doesnt matter", null, "doesnt matter", _loadBalancerOptions, "http", _qoSOptions, _handlerOptions);
+
+            this.Given(_ => GivenTheConfiguration(configuration, "/geoffisthebest/"))
+                .When(_ => WhenICreate())
+                .And(_ => GivenTheConfiguration(configuration, "/geoffisthebest/"))
+                .When(_ => WhenICreateAgain())
+                .Then(_ => ThenTheDownstreamRoutesAreTheSameReference())
+                .BDDfy();
+        }
+
+        [Fact]
+        public void should_not_cache_downstream_route()
+        {
+            var configuration = new InternalConfiguration(null, "doesnt matter", null, "doesnt matter", _loadBalancerOptions, "http", _qoSOptions, _handlerOptions);
+
+            this.Given(_ => GivenTheConfiguration(configuration, "/geoffistheworst/"))
+                .When(_ => WhenICreate())
+                .And(_ => GivenTheConfiguration(configuration, "/geoffisthebest/"))
+                .When(_ => WhenICreateAgain())
+                .Then(_ => ThenTheDownstreamRoutesAreTheNotSameReference())
+                .BDDfy();
+        }
+
         [Fact]
         public void should_create_downstream_route_with_no_path()
         {
@@ -62,6 +90,30 @@ namespace Ocelot.UnitTests.DownstreamRouteFinder
                 .BDDfy();
         }
 
+        [Fact]
+        public void should_create_downstream_route_with_only_first_segment_no_traling_slash()
+        {
+            var upstreamUrlPath = "/auth";
+            var configuration = new InternalConfiguration(null, "doesnt matter", null, "doesnt matter", _loadBalancerOptions, "http", _qoSOptions, _handlerOptions);
+
+            this.Given(_ => GivenTheConfiguration(configuration, upstreamUrlPath))
+                .When(_ => WhenICreate())
+                .Then(_ => ThenTheDownstreamPathIsForwardSlash())
+                .BDDfy();
+        }
+
+        [Fact]
+        public void should_create_downstream_route_with_segments_no_traling_slash()
+        {
+            var upstreamUrlPath = "/auth/test";
+            var configuration = new InternalConfiguration(null, "doesnt matter", null, "doesnt matter", _loadBalancerOptions, "http", _qoSOptions, _handlerOptions);
+
+            this.Given(_ => GivenTheConfiguration(configuration, upstreamUrlPath))
+                .When(_ => WhenICreate())
+                .Then(_ => ThenThePathDoesNotHaveTrailingSlash())
+                .BDDfy();
+        }
+
         [Fact]
         public void should_create_downstream_route_and_remove_query_string()
         {
@@ -143,6 +195,13 @@ namespace Ocelot.UnitTests.DownstreamRouteFinder
             _result.Data.ReRoute.DownstreamReRoute[0].LoadBalancerKey.ShouldBe("/auth/|GET");
         }
 
+        private void ThenThePathDoesNotHaveTrailingSlash()
+        {
+            _result.Data.ReRoute.DownstreamReRoute[0].DownstreamPathTemplate.Value.ShouldBe("/test");
+            _result.Data.ReRoute.DownstreamReRoute[0].ServiceName.ShouldBe("auth");
+            _result.Data.ReRoute.DownstreamReRoute[0].LoadBalancerKey.ShouldBe("/auth/test|GET");
+        }
+
         private void ThenTheQueryStringIsRemoved()
         {
             _result.Data.ReRoute.DownstreamReRoute[0].DownstreamPathTemplate.Value.ShouldBe("/test");
@@ -190,5 +249,20 @@ namespace Ocelot.UnitTests.DownstreamRouteFinder
         {
             _result = _creator.Get(_upstreamUrlPath, _upstreamHttpMethod, _configuration, _upstreamHost);
         }
+
+        private void WhenICreateAgain()
+        {
+            _resultTwo = _creator.Get(_upstreamUrlPath, _upstreamHttpMethod, _configuration, _upstreamHost);
+        }
+
+        private void ThenTheDownstreamRoutesAreTheSameReference()
+        {
+            _result.ShouldBe(_resultTwo);
+        }
+
+        private void ThenTheDownstreamRoutesAreTheNotSameReference()
+        {
+            _result.ShouldNotBe(_resultTwo);
+        }
     }
 }