Support custom subscriptions response.

src/Dapr.AspNetCore/DaprEndpointRouteBuilderExtensions.cs

@@ -184,7 +184,13 @@ private static IEndpointConventionBuilder CreateSubscribeEndPoint(IEndpointRoute
 
                         return subscription;
                     })
-                    .OrderBy(e => (e.PubsubName, e.Topic));
+                    .OrderBy(e => (e.PubsubName, e.Topic))
+                    .ToList();
+
+                if (options != null && options.SubscriptionsCallback != null)
+                {
+                    await options.SubscriptionsCallback(subscriptions);
+                }
 
                 await context.Response.WriteAsync(JsonSerializer.Serialize(subscriptions,
                     new JsonSerializerOptions

src/Dapr.AspNetCore/SubscribeOptions.cs

@@ -11,6 +11,10 @@
 // limitations under the License.
 // ------------------------------------------------------------------------
 
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+
 namespace Dapr
 {
     /// <summary>
@@ -22,5 +26,10 @@ public class SubscribeOptions
         /// Gets or Sets a value which indicates whether to enable or disable processing raw messages.
         /// </summary>
         public bool EnableRawPayload { get; set; }
+
+        /// <summary>
+        /// An optional delegate used to configure the subscriptions.
+        /// </summary>
+        public Func<List<Subscription>, Task> SubscriptionsCallback { get; set; }
     }
 }

src/Dapr.AspNetCore/Subscription.cs

@@ -18,7 +18,7 @@ namespace Dapr
     /// <summary>
     /// This class defines subscribe endpoint response
     /// </summary>
-    internal class Subscription
+    public class Subscription
     {
         /// <summary>
         /// Gets or sets the topic name.
@@ -44,7 +44,7 @@ internal class Subscription
         /// Gets or sets the metadata.
         /// </summary>
         public Metadata Metadata { get; set; }
-        
+
         /// <summary>
         /// Gets or sets the deadletter topic.
         /// </summary>
@@ -59,10 +59,17 @@ internal class Subscription
     /// <summary>
     /// This class defines the metadata for subscribe endpoint.
     /// </summary>
-    internal class Metadata : Dictionary<string, string>
+    public class Metadata : Dictionary<string, string>
     {
+        /// <summary>
+        /// Initializes a new instance of the Metadata class.
+        /// </summary>
         public Metadata() { }
 
+        /// <summary>
+        /// Initializes a new instance of the Metadata class.
+        /// </summary>
+        /// <param name="dictionary"></param>
         public Metadata(IDictionary<string, string> dictionary) : base(dictionary) { }
 
         /// <summary>
@@ -71,7 +78,10 @@ public Metadata(IDictionary<string, string> dictionary) : base(dictionary) { }
         internal const string RawPayload = "rawPayload";
     }
 
-    internal class Routes
+    /// <summary>
+    /// This class defines the routes for subscribe endpoint.
+    /// </summary>
+    public class Routes
     {
         /// <summary>
         /// Gets or sets the default route
@@ -84,7 +94,10 @@ internal class Routes
         public List<Rule> Rules { get; set; }
     }
 
-    internal class Rule
+    /// <summary>
+    /// This class defines the rule for subscribe endpoint.
+    /// </summary>
+    public class Rule
     {
         /// <summary>
         /// Gets or sets the CEL expression to match this route.
@@ -97,7 +110,10 @@ internal class Rule
         public string Path { get; set; }
     }
 
-    internal class DaprTopicBulkSubscribe
+    /// <summary>
+    /// This class defines the bulk subscribe options for subscribe endpoint.
+    /// </summary>
+    public class DaprTopicBulkSubscribe
     {
         /// <summary>
         /// Gets or sets whether bulk subscribe option is enabled for a topic.

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

@@ -59,7 +59,19 @@ public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
 
             app.UseEndpoints(endpoints =>
             {
-                endpoints.MapSubscribeHandler();
+                endpoints.MapSubscribeHandler(new SubscribeOptions()
+                {
+                    SubscriptionsCallback = subscriptions =>
+                    {
+                        subscriptions.Add(new Subscription()
+                        {
+                            PubsubName = "dynamic-pubsub",
+                            Topic = "dynamic-topic",
+                            Route = "/dynamic-route"
+                        });
+                        return Task.CompletedTask;
+                    }
+                });
                 endpoints.MapControllers();
 
                 endpoints.MapPost("/topic-a", context => Task.CompletedTask).WithTopic("testpubsub", "A").WithTopic("testpubsub", "A.1");

test/Dapr.AspNetCore.IntegrationTest/SubscribeEndpointTest.cs

@@ -11,6 +11,8 @@
 // limitations under the License.
 // ------------------------------------------------------------------------
 
+using System;
+
 namespace Dapr.AspNetCore.IntegrationTest
 {
     using System;
@@ -40,9 +42,9 @@ public async Task SubscribeEndpoint_ReportsTopics()
                     var json = await JsonSerializer.DeserializeAsync<JsonElement>(stream);
 
                     json.ValueKind.Should().Be(JsonValueKind.Array);
-                    json.GetArrayLength().Should().Be(18);
+                    json.GetArrayLength().Should().Be(19);
 
-                    var subscriptions = new List<(string PubsubName, string Topic, string Route, string rawPayload, 
+                    var subscriptions = new List<(string PubsubName, string Topic, string Route, string rawPayload,
                         string match, string metadata, string DeadLetterTopic, string bulkSubscribeMetadata)>();
 
                     foreach (var element in json.EnumerateArray())
@@ -86,7 +88,7 @@ public async Task SubscribeEndpoint_ReportsTopics()
 
                         if (element.TryGetProperty("route", out JsonElement route))
                         {
-                            subscriptions.Add((pubsubName, topic, route.GetString(), rawPayload, string.Empty, 
+                            subscriptions.Add((pubsubName, topic, route.GetString(), rawPayload, string.Empty,
                                 originalMetadataString, deadLetterTopic, bulkSubscribeMetadata));
                         }
                         else if (element.TryGetProperty("routes", out JsonElement routes))
@@ -97,13 +99,13 @@ public async Task SubscribeEndpoint_ReportsTopics()
                                 {
                                     var match = rule.GetProperty("match").GetString();
                                     var path = rule.GetProperty("path").GetString();
-                                    subscriptions.Add((pubsubName, topic, path, rawPayload, match, 
+                                    subscriptions.Add((pubsubName, topic, path, rawPayload, match,
                                         originalMetadataString, deadLetterTopic, bulkSubscribeMetadata));
                                 }
                             }
                             if (routes.TryGetProperty("default", out JsonElement defaultProperty))
                             {
-                                subscriptions.Add((pubsubName, topic, defaultProperty.GetString(), rawPayload, 
+                                subscriptions.Add((pubsubName, topic, defaultProperty.GetString(), rawPayload,
                                     string.Empty, originalMetadataString, deadLetterTopic, bulkSubscribeMetadata));
                             }
                         }
@@ -119,18 +121,19 @@ public async Task SubscribeEndpoint_ReportsTopics()
                     subscriptions.Should().Contain(("pubsub", "E", "E", string.Empty, string.Empty, string.Empty, string.Empty, String.Empty));
                     subscriptions.Should().Contain(("pubsub", "E", "E-Critical", string.Empty, "event.type == \"critical\"", string.Empty, string.Empty, String.Empty));
                     subscriptions.Should().Contain(("pubsub", "E", "E-Important", string.Empty, "event.type == \"important\"", string.Empty, string.Empty, String.Empty));
-                    subscriptions.Should().Contain(("pubsub", "F", "multiTopicAttr", string.Empty, string.Empty, string.Empty, string.Empty, 
+                    subscriptions.Should().Contain(("pubsub", "F", "multiTopicAttr", string.Empty, string.Empty, string.Empty, string.Empty,
                         "{\"enabled\":true,\"maxMessagesCount\":100,\"maxAwaitDurationMs\":1000}"));
                     subscriptions.Should().Contain(("pubsub", "F.1", "multiTopicAttr", "true", string.Empty, string.Empty, string.Empty, String.Empty));
-                    subscriptions.Should().Contain(("pubsub", "G", "G", string.Empty, string.Empty, string.Empty, "deadLetterTopicName", 
+                    subscriptions.Should().Contain(("pubsub", "G", "G", string.Empty, string.Empty, string.Empty, "deadLetterTopicName",
                         "{\"enabled\":true,\"maxMessagesCount\":300,\"maxAwaitDurationMs\":1000}"));
                     subscriptions.Should().Contain(("pubsub", "splitTopicBuilder", "splitTopics", string.Empty, string.Empty, string.Empty, string.Empty, String.Empty));
                     subscriptions.Should().Contain(("pubsub", "splitTopicAttr", "splitTopics", "true", string.Empty, string.Empty, string.Empty, String.Empty));
                     subscriptions.Should().Contain(("pubsub", "metadata", "multiMetadataTopicAttr", string.Empty, string.Empty, "n1=v1;n2=v2,v3", string.Empty, String.Empty));
-                    subscriptions.Should().Contain(("pubsub", "metadata.1", "multiMetadataTopicAttr", "true", string.Empty, "n1=v1", string.Empty, 
+                    subscriptions.Should().Contain(("pubsub", "metadata.1", "multiMetadataTopicAttr", "true", string.Empty, "n1=v1", string.Empty,
                         "{\"enabled\":true,\"maxMessagesCount\":500,\"maxAwaitDurationMs\":2000}"));
                     subscriptions.Should().Contain(("pubsub", "splitMetadataTopicBuilder", "splitMetadataTopics", string.Empty, string.Empty, "n1=v1;n2=v1", string.Empty, String.Empty));
                     subscriptions.Should().Contain(("pubsub", "metadataseparatorbyemptytring", "topicmetadataseparatorattrbyemptytring", string.Empty, string.Empty, "n1=v1,", string.Empty, String.Empty));
+                    subscriptions.Should().Contain(("dynamic-pubsub", "dynamic-topic", "/dynamic-route", string.Empty, string.Empty, string.Empty, string.Empty, string.Empty));
                     // Test priority route sorting
                     var eTopic = subscriptions.FindAll(e => e.Topic == "E");
                     eTopic.Count.Should().Be(3);