#2248 Ensure correct mapping of RouteKeysConfig arrays in aggregates

src/Ocelot/Configuration/Creator/AggregatesCreator.cs

@@ -26,15 +26,16 @@ private Route SetUpAggregateRoute(IEnumerable<Route> routes, FileAggregateRoute
     {
         var applicableRoutes = new List<DownstreamRoute>();
         var allRoutes = routes.SelectMany(x => x.DownstreamRoute);
-        var downstreamRoutes = aggregateRoute.RouteKeys.Select(routeKey => allRoutes.FirstOrDefault(q => q.Key == routeKey));
-        foreach (var downstreamRoute in downstreamRoutes)
-        {
-            if (downstreamRoute == null)
-            {
-                return null;
-            }
-
-            applicableRoutes.Add(downstreamRoute);
+        var orderedKeys = aggregateRoute.RouteKeys.ToList();
+        foreach (var key in orderedKeys)
+        {
+            var match = allRoutes.FirstOrDefault(r => r.Key == key);
+            if (match is null)
+            {
+                return null;
+            }
+
+            applicableRoutes.Add(match);
         }
 
         var upstreamTemplatePattern = _creator.Create(aggregateRoute);

src/Ocelot/Multiplexer/MultiplexingMiddleware.cs

@@ -166,11 +166,13 @@ private IEnumerable<Task<HttpContext>> ProcessRouteWithComplexAggregation(Aggreg
         JToken jObject, HttpContext httpContext, DownstreamRoute downstreamRoute)
     {
         var processing = new List<Task<HttpContext>>();
-        var values = jObject.SelectTokens(matchAdvancedAgg.JsonPath).Select(s => s.ToString()).Distinct();
+        var values = jObject.SelectTokens(matchAdvancedAgg.JsonPath).Select(s => s.ToString()).Distinct().ToList();
         foreach (var value in values)
         {
-            var tPnv = httpContext.Items.TemplatePlaceholderNameAndValues();
-            tPnv.Add(new PlaceholderNameAndValue('{' + matchAdvancedAgg.Parameter + '}', value));
+            var tPnv = new List<PlaceholderNameAndValue>(httpContext.Items.TemplatePlaceholderNameAndValues())
+            {
+                new('{' + matchAdvancedAgg.Parameter + '}', value),
+            };
             processing.Add(ProcessRouteAsync(httpContext, downstreamRoute, tPnv));
         }
 
@@ -255,6 +257,16 @@ protected virtual Task MapAsync(HttpContext httpContext, Route route, List<HttpC
             return Task.CompletedTask;
         }
 
+        // ensure each context retains its correct aggregate key for proper response mapping
+        if (route.DownstreamRouteConfig != null && route.DownstreamRouteConfig.Count > 0)
+        {
+            for (int i = 0; i < contexts.Count && i < route.DownstreamRouteConfig.Count; i++)
+            {
+                var key = route.DownstreamRouteConfig[i].RouteKey;
+                contexts[i].Items["CurrentAggregateRouteKey"] = key;
+            }
+        }
+
         var aggregator = _factory.Get(route);
         return aggregator.Aggregate(route, httpContext, contexts);
     }

test/Ocelot.AcceptanceTests/AggregateTests.cs

@@ -685,6 +685,134 @@ public void Should_return_response_200_with_copied_form_sent_on_multiple_service
             .BDDfy();
     }
 
+    [Fact]
+    [Trait("Bug", "2248")]
+    [Trait("PR", "2328")] // https://github.com/ThreeMammals/Ocelot/pull/2328
+    public void Should_match_downstream_routes_using_route_keys_array()
+    {
+        var portUser = PortFinder.GetRandomPort();
+        var userRoute = GivenRoute(portUser, "/user", "/user");
+        userRoute.Key = "User";
+
+        var portProduct = PortFinder.GetRandomPort();
+        var productRoute = GivenRoute(portProduct, "/product", "/product");
+        productRoute.Key = "Product";
+
+        var aggregate = new FileAggregateRoute
+        {
+            RouteKeys = new() { "User", "Product" },
+            UpstreamPathTemplate = "/composite",
+            UpstreamHttpMethod = ["Get"],
+        };
+
+        var configuration = GivenConfiguration(userRoute, productRoute);
+        configuration.Aggregates = new() { aggregate };
+        this.Given(_ => GivenThereIsAConfiguration(configuration))
+            .And(_ => GivenOcelotIsRunning())
+            .And(_ => GivenThereIsAServiceRunningOn(portUser, "/user", MapGetUser))
+            .And(_ => GivenThereIsAServiceRunningOn(portProduct, "/product", MapGetProduct))
+            .When(_ => WhenIGetUrlOnTheApiGateway("/composite"))
+            .Then(_ => ThenTheStatusCodeShouldBeOK())
+            .BDDfy();
+    }
+
+    [Fact]
+    [Trait("Bug", "2248")]
+    [Trait("PR", "2328")] // https://github.com/ThreeMammals/Ocelot/pull/2328
+    public void Should_expand_jsonpath_array_into_multiple_parameterized_calls()
+    {
+        var commentsPort = PortFinder.GetRandomPort();
+        var usersPort = PortFinder.GetRandomPort();
+
+        var comments = new FileRoute
+        {
+            Key = "comments",
+            DownstreamScheme = "http",
+            DownstreamHostAndPorts = new() { new("localhost", commentsPort) },
+            DownstreamPathTemplate = "/comments",
+            UpstreamPathTemplate = "/comments",
+            UpstreamHttpMethod = [HttpMethods.Get],
+        };
+
+        var user = new FileRoute
+        {
+            Key = "user",
+            DownstreamScheme = "http",
+            DownstreamHostAndPorts = new() { new("localhost", usersPort) },
+            DownstreamPathTemplate = "/users/{userId}",
+            UpstreamPathTemplate = "/users/{userId}",
+            UpstreamHttpMethod = [HttpMethods.Get],
+        };
+
+        var aggregate = new FileAggregateRoute
+        {
+            UpstreamPathTemplate = "/aggregatecommentuser",
+            UpstreamHttpMethod = [HttpMethods.Get],
+            RouteKeys = ["comments", "user"],
+            RouteKeysConfig = new()
+        {
+            new AggregateRouteConfig
+            {
+                RouteKey = "user",
+                JsonPath = "$[*].userId",
+                Parameter = "userId",
+            },
+        },
+        };
+
+        var config = new FileConfiguration
+        {
+            Routes = new() { comments, user },
+            Aggregates = new() { aggregate },
+        };
+
+        handler.GivenThereIsAServiceRunningOn(commentsPort, async ctx =>
+        {
+            if (ctx.Request.Path.Value == "/comments")
+            {
+                ctx.Response.StatusCode = 200;
+                ctx.Response.ContentType = "application/json";
+                await ctx.Response.WriteAsync("[{\"id\":1,\"userId\":1},{\"id\":2,\"userId\":2}]");
+            }
+            else
+            {
+                ctx.Response.StatusCode = 404;
+            }
+        });
+
+        handler.GivenThereIsAServiceRunningOn(usersPort, async ctx =>
+        {
+            var parts = ctx.Request.Path.Value?.Trim('/').Split('/');
+            var ok = parts?.Length == 2 && parts[0] == "users" && int.TryParse(parts[1], out var id);
+            ctx.Response.StatusCode = ok ? 200 : 400;
+            ctx.Response.ContentType = "application/json";
+            await ctx.Response.WriteAsync(ok
+                ? $"{{\"id\":{parts![1]},\"name\":\"User-{parts[1]}\"}}"
+                : "{\"error\":\"bad id\"}");
+        });
+
+        var expected =
+            "{\"comments\":[{\"id\":1,\"userId\":1},{\"id\":2,\"userId\":2}],\"user\":[{\"id\":1,\"name\":\"User-1\"},{\"id\":2,\"name\":\"User-2\"}]}";
+
+        this.Given(_ => GivenThereIsAConfiguration(config))
+            .And(_ => GivenOcelotIsRunning())
+            .When(_ => WhenIGetUrlOnTheApiGateway("/aggregatecommentuser"))
+            .Then(_ => ThenTheStatusCodeShouldBe(HttpStatusCode.OK))
+            .And(_ => ThenTheResponseBodyShouldBe(expected))
+            .BDDfy();
+    }
+
+    Task MapGetUser(HttpContext ctx)
+    {
+        ctx.Response.StatusCode = 200;
+        return ctx.Response.WriteAsync("OK-user");
+    }
+    Task MapGetProduct(HttpContext ctx)
+    {
+        ctx.Response.StatusCode = 200;
+        return ctx.Response.WriteAsync("OK-product");
+    }
+
     private static string FormatFormCollection(IFormCollection reqForm)
     {
         var sb = new StringBuilder()