Adds support for providing pubsub and topic names during runtime.

- Fixes #680

src/Dapr.AspNetCore/DaprEndpointConventionBuilderExtensions.cs

@@ -14,7 +14,7 @@ namespace Microsoft.AspNetCore.Builder
     public static class DaprEndpointConventionBuilderExtensions
     {
         /// <summary>
-        /// Adds <see cref="TopicAttribute" /> metadata to the provided <see cref="IEndpointConventionBuilder" />.
+        /// Adds <see cref="ITopicMetadata" /> metadata to the provided <see cref="IEndpointConventionBuilder" />.
         /// </summary>
         /// <param name="builder">The <see cref="IEndpointConventionBuilder" />.</param>\
         /// <param name="pubsubName">The name of the pubsub component to use.</param>

src/Dapr.AspNetCore/DaprEndpointRouteBuilderExtensions.cs

@@ -39,9 +39,9 @@ namespace Microsoft.AspNetCore.Builder
                 var dataSource = context.RequestServices.GetRequiredService<EndpointDataSource>();
                 var entries = dataSource.Endpoints
                     .OfType<RouteEndpoint>()
-                    .Where(e => e.Metadata.GetMetadata<TopicAttribute>()?.Name != null)   // only endpoints which have  TopicAttribute with not null Name.
+                    .Where(e => e.Metadata.GetMetadata<ITopicMetadata>()?.Name != null)   // only endpoints which have  TopicAttribute with not null Name.
                     .Distinct()
-                    .Select(e => (e.Metadata.GetMetadata<TopicAttribute>().PubsubName, e.Metadata.GetMetadata<TopicAttribute>().Name, e.RoutePattern));
+                    .Select(e => (e.Metadata.GetMetadata<ITopicMetadata>().PubsubName, e.Metadata.GetMetadata<ITopicMetadata>().Name, e.RoutePattern));
 
                 context.Response.ContentType = "application/json";
                 using var writer = new Utf8JsonWriter(context.Response.BodyWriter);

src/Dapr.AspNetCore/ITopicMetadata.cs

@@ -0,0 +1,18 @@
+namespace Dapr
+{
+    /// <summary>
+    /// Metadata that describes an endpoint as a subscriber to a topic.
+    /// </summary>
+    public interface ITopicMetadata
+    {
+        /// <summary>
+        /// Gets the topic name.
+        /// </summary>
+        string Name { get; }
+
+        /// <summary>
+        /// Gets the pubsub component name name.
+        /// </summary>
+        string PubsubName { get; }
+    }
+}

src/Dapr.AspNetCore/TopicAttribute.cs

@@ -10,7 +10,7 @@ namespace Dapr
     /// <summary>
     /// Metadata that describes an endpoint as a subscriber to a topic.
     /// </summary>
-    public class TopicAttribute : Attribute
+    public class TopicAttribute : Attribute, ITopicMetadata
     {
         /// <summary>
         /// Initializes a new instance of the <see cref="TopicAttribute" /> class.
@@ -26,14 +26,10 @@ namespace Dapr
             this.PubsubName = pubsubName;
         }
 
-        /// <summary>
-        /// Gets the topic name.
-        /// </summary>
+        /// <inheritdoc/>
         public string Name { get; }
 
-        /// <summary>
-        /// Gets the pubsub component name name.
-        /// </summary>
+        /// <inheritdoc/>
         public string PubsubName { get; }
     }
 }

test/Dapr.AspNetCore.IntegrationTest.App/CustomTopicAttribute.cs

@@ -0,0 +1,22 @@
+// ------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+// ------------------------------------------------------------
+
+namespace Dapr.AspNetCore.IntegrationTest.App
+{
+    using System;
+
+    public class CustomTopicAttribute : Attribute, ITopicMetadata
+    {
+        public CustomTopicAttribute(string pubsubName, string name)
+        {
+            this.Name = "custom-" + name;
+            this.PubsubName = "custom-" + pubsubName;
+        }
+
+        public string Name { get; }
+
+        public string PubsubName { get; }
+    }
+}

test/Dapr.AspNetCore.IntegrationTest.App/DaprController.cs

@@ -22,6 +22,12 @@ namespace Dapr.AspNetCore.IntegrationTest.App
         {
         }
 
+        [CustomTopic("pubsub", "C")]
+        [HttpPost("/C")]
+        public void TopicC()
+        {
+        }
+
         [Topic("pubsub", "register-user")]
         [HttpPost("/register-user")]
         public ActionResult<UserInfo> RegisterUser(UserInfo user)

test/Dapr.AspNetCore.IntegrationTest/SubscribeEndpointTest.cs

@@ -30,24 +30,21 @@ namespace Dapr.AspNetCore.IntegrationTest
                     var json = await JsonSerializer.DeserializeAsync<JsonElement>(stream);
 
                     json.ValueKind.Should().Be(JsonValueKind.Array);
-                    json.GetArrayLength().Should().Be(4);
-                    var topics = new List<string>();
-                    var routes = new List<string>();
+                    json.GetArrayLength().Should().Be(5);
+                    var metadata = new List<(string PubsubName, string Topic, string Route)>();
                     foreach (var element in json.EnumerateArray())
                     {
-                        topics.Add(element.GetProperty("topic").GetString());
-                        routes.Add(element.GetProperty("route").GetString());
+                        var pubsubName = element.GetProperty("pubsubName").GetString();
+                        var topic = element.GetProperty("topic").GetString();
+                        var route = element.GetProperty("route").GetString();
+                        metadata.Add((pubsubName, topic, route));
                     }
 
-                    topics.Should().Contain("A");
-                    topics.Should().Contain("B");
-                    topics.Should().Contain("register-user");
-                    topics.Should().Contain("register-user-plaintext");
-
-                    routes.Should().Contain("B");
-                    routes.Should().Contain("topic-a");
-                    routes.Should().Contain("register-user");
-                    routes.Should().Contain("register-user-plaintext");
+                    metadata.Should().Contain(("testpubsub", "A", "topic-a"));
+                    metadata.Should().Contain(("pubsub", "B", "B"));
+                    metadata.Should().Contain(("custom-pubsub", "custom-C", "C"));
+                    metadata.Should().Contain(("pubsub", "register-user", "register-user"));
+                    metadata.Should().Contain(("pubsub", "register-user-plaintext", "register-user-plaintext"));
                 }
             }
         }