tell slack not to not retry on error (exceptions)

Samples/HelloWorld/Program.cs

@@ -18,7 +18,8 @@
     .AddMessageActionsHandler<DoOtherStuff>()
     .AddAppMentionHandler<DoStuff>()
     .AddTeamJoinHandler<OnTeamJoins>()
-    .AddEmojiChangedHandler<OnEmojiChanged>();
+    .AddEmojiChangedHandler<OnEmojiChanged>()
+    .AddAppMentionHandler<IThrowExceptions>();
 
 
 var app = builder.Build();
@@ -72,3 +73,13 @@ public Task<EventHandledResponse> Handle(EventMetaData eventMetadata, EmojiChang
         return Task.FromResult(new EventHandledResponse("OK"));
     }
 }
+
+class IThrowExceptions : IHandleAppMentions
+{
+    public bool ShouldHandle(AppMentionEvent slackEvent) => slackEvent.Text.Contains("throw-exception");
+
+    public Task<EventHandledResponse> Handle(EventMetaData eventMetadata, AppMentionEvent slackEvent)
+    {
+        throw new Exception("Quack! Something went wrong!");
+    }
+}

Samples/HelloWorld/test.http

@@ -1,5 +1,5 @@
 # Mimicks a payload slack would send for app_mention events, like "@yourbot dostuff" in this case:
-GET http://localhost:1337/
+GET http://localhost:5000/
 X-Slack-Request-Timestamp: 12331231
 X-Slack-Signature: v0:abc123etcetc
 
@@ -8,14 +8,14 @@ X-Slack-Signature: v0:abc123etcetc
     "event": {
         "type": "app_mention",
         "user": "USRAR1YTV",
-        "text" : "<@BOT123> dostuff",
+        "text" : "<@BOT123> dostuff and throw-exception",
         "channel": "C92QZTVEF"
     }
 }
 
 ###
 # Verification request
-GET http://localhost:1337
+GET http://localhost:5000
 
 {
     "token": "Jhj5dZrVaK7ZwHHjRyZWjbDl",

source/src/Slackbot.Net.Endpoints/Hosting/IAppBuilderExtensions.cs

@@ -12,6 +12,7 @@ public static IApplicationBuilder UseSlackbot(this IApplicationBuilder app, bool
             app.UseMiddleware<SlackbotEventAuthMiddleware>();
         }
 
+        app.UseMiddleware<ErrorHandlingMiddleware>();
         app.UseMiddleware<HttpItemsManager>();
         app.MapWhen(Challenge.ShouldRun, b => b.UseMiddleware<Challenge>());
         app.MapWhen(Uninstall.ShouldRun, b => b.UseMiddleware<Uninstall>());

source/src/Slackbot.Net.Endpoints/Middlewares/AppHomeOpenedEvents.cs

@@ -23,16 +23,9 @@ public async Task Invoke(HttpContext context)
         else
         {
             logger.LogInformation($"Handling using {handler.GetType()}");
-            try
-            {
-                logger.LogInformation($"Handling using {handler.GetType()}");
-                var response = await handler.Handle(metadata, appHomeOpenedEvent);
-                logger.LogInformation(response.Response);
-            }
-            catch (Exception e)
-            {
-                logger.LogError(e, e.Message);
-            }
+            logger.LogInformation($"Handling using {handler.GetType()}");
+            var response = await handler.Handle(metadata, appHomeOpenedEvent);
+            logger.LogInformation(response.Response);
         }
 
         await next(context);

source/src/Slackbot.Net.Endpoints/Middlewares/AppMentionEvents.cs

@@ -1,3 +1,4 @@
+using System.Runtime.ExceptionServices;
 using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.Logging;
 using Slackbot.Net.Endpoints.Abstractions;
@@ -24,6 +25,8 @@ public async Task Invoke(HttpContext context)
             ["Slack_Channel"] = appMentionEvent?.Channel,
             ["Slack_User"] = appMentionEvent?.User
         });
+        ExceptionDispatchInfo capturedException = null;
+
         foreach (var handler in handlers)
         {
             try
@@ -33,12 +36,14 @@ public async Task Invoke(HttpContext context)
             }
             catch (Exception e)
             {
-                logger.LogError(e, e.Message);
+                capturedException = ExceptionDispatchInfo.Capture(e);
             }
         }
 
-
-        context.Response.StatusCode = 200;
+        if (capturedException != null)
+        {
+            capturedException?.Throw();
+        }
     }
 
     public static bool ShouldRun(HttpContext ctx)

source/src/Slackbot.Net.Endpoints/Middlewares/Challenge.cs

@@ -16,7 +16,6 @@ public Challenge(RequestDelegate next, ILogger<Challenge> logger)
     public async Task Invoke(HttpContext context)
     {
         var challenge = context.Items[HttpItemKeys.ChallengeKey];
-
         _logger.LogInformation($"Handling challenge request. Challenge: {challenge}");
         context.Response.StatusCode = 200;
         context.Response.ContentType = "application/json";

source/src/Slackbot.Net.Endpoints/Middlewares/EmojiChangedEvents.cs

@@ -6,7 +6,9 @@
 namespace Slackbot.Net.Endpoints.Middlewares;
 
 public class EmojiChangedEvents(
+#pragma warning disable CS9113 // Parameter is unread.
     RequestDelegate next,
+#pragma warning restore CS9113 // Parameter is unread.
     ILogger<EmojiChangedEvents> logger,
     IEnumerable<IHandleEmojiChanged> responseHandlers
 )
@@ -24,16 +26,9 @@ public async Task Invoke(HttpContext context)
         else
         {
             logger.LogInformation("Handling using {HandlerType}", handler.GetType());
-            try
-            {
-                logger.LogInformation("Handling using {HandlerType}", handler.GetType());
-                var response = await handler.Handle(metadata, emojiChanged);
-                logger.LogInformation("Handler response: {Response}", response.Response);
-            }
-            catch (Exception e)
-            {
-                logger.LogError(e, e.Message);
-            }
+            logger.LogInformation("Handling using {HandlerType}", handler.GetType());
+            var response = await handler.Handle(metadata, emojiChanged);
+            logger.LogInformation("Handler response: {Response}", response.Response);
         }
 
         context.Response.StatusCode = 200;

source/src/Slackbot.Net.Endpoints/Middlewares/ErrorHandlingMiddleware.cs

@@ -0,0 +1,22 @@
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Logging;
+
+namespace Slackbot.Net.Endpoints.Middlewares;
+
+public class ErrorHandlingMiddleware(RequestDelegate next, ILogger<HttpItemsManager> logger)
+{
+    public async Task InvokeAsync(HttpContext context)
+    {
+        try
+        {
+            await next(context);
+        }
+        catch (Exception e)
+        {
+            logger.LogError(e, e.Message);
+            context.Response.Headers.Append("x-slack-no-retry", "1");
+            context.Response.StatusCode = 500;
+            await context.Response.WriteAsync("An error occurred while processing the slack event request. Plz do not retry.");
+        }
+    }
+}

source/src/Slackbot.Net.Endpoints/Middlewares/HttpItemsManager.cs

@@ -35,7 +35,7 @@ public async Task Invoke(HttpContext context)
                 else
                 {
                     var metadata = JsonSerializer.Deserialize<EventMetaData>(body, WebOptions);
-                    if (jObject.RootElement.GetProperty("event") is JsonElement @event)
+                    if (jObject.RootElement.GetProperty("event") is var @event)
                     {
                         var slackEvent = ToEventType(@event, body);
                         context.Items.Add(HttpItemKeys.EventMetadataKey, metadata);
@@ -78,7 +78,7 @@ private static SlackEvent ToEventType(JsonElement eventJson, string raw)
             case EventTypes.TeamJoin:
                 return JsonSerializer.Deserialize<TeamJoinEvent>(json, WebOptions);
             case EventTypes.EmojiChanged:
-                return JsonSerializer.Deserialize<EmojiChangedEvent>(json, WebOptions);            
+                return JsonSerializer.Deserialize<EmojiChangedEvent>(json, WebOptions);
             default:
                 var unknownSlackEvent = JsonSerializer.Deserialize<UnknownSlackEvent>(json, WebOptions);
                 unknownSlackEvent.RawJson = raw;

source/src/Slackbot.Net.Endpoints/Middlewares/InteractiveEvents.cs

@@ -59,16 +59,8 @@ private async Task HandleMessageAction(MessageActionInteraction messageAction)
         else
         {
             logger.LogInformation($"Handling using {handler.GetType()}");
-            try
-            {
-                logger.LogInformation($"Handling using {handler.GetType()}");
-                var response = await handler.Handle(messageAction);
-                logger.LogInformation(response.Response);
-            }
-            catch (Exception e)
-            {
-                logger.LogError(e, e.Message);
-            }
+            var response = await handler.Handle(messageAction);
+            logger.LogInformation(response.Response);
         }
     }
 

source/src/Slackbot.Net.Endpoints/Middlewares/MemberJoinedEvents.cs

@@ -32,19 +32,9 @@ public async Task Invoke(HttpContext context)
         else
         {
             _logger.LogInformation($"Handling using {handler.GetType()}");
-            try
-            {
-                _logger.LogInformation($"Handling using {handler.GetType()}");
-                var response = await handler.Handle(metadata, memberJoinedChannelEvent);
-                _logger.LogInformation(response.Response);
-            }
-            catch (Exception e)
-            {
-                _logger.LogError(e, e.Message);
-            }
+            var response = await handler.Handle(metadata, memberJoinedChannelEvent);
+            _logger.LogInformation(response.Response);
         }
-
-        context.Response.StatusCode = 200;
     }
 
     public static bool ShouldRun(HttpContext ctx)

source/src/Slackbot.Net.Endpoints/Middlewares/TeamJoinEvents.cs

@@ -6,7 +6,9 @@
 namespace Slackbot.Net.Endpoints.Middlewares;
 
 public class TeamJoinEvents(
+#pragma warning disable CS9113 // Parameter is unread.
     RequestDelegate next,
+#pragma warning restore CS9113 // Parameter is unread.
     ILogger<TeamJoinEvents> logger,
     IEnumerable<IHandleTeamJoin> responseHandlers
 )
@@ -24,16 +26,8 @@ public async Task Invoke(HttpContext context)
         else
         {
             logger.LogInformation("Handling using {HandlerType}", handler.GetType());
-            try
-            {
-                logger.LogInformation("Handling using {HandlerType}", handler.GetType());
-                var response = await handler.Handle(metadata, teamJoinEvent);
-                logger.LogInformation("Handler response: {Response}", response.Response);
-            }
-            catch (Exception e)
-            {
-                logger.LogError(e, e.Message);
-            }
+            var response = await handler.Handle(metadata, teamJoinEvent);
+            logger.LogInformation("Handler response: {Response}", response.Response);
         }
 
         context.Response.StatusCode = 200;

source/src/Slackbot.Net.Endpoints/Models/Events/EmojiChangedEvent.cs

@@ -11,15 +11,15 @@ public class EmojiChangedEvent : SlackEvent
     public string SubType { get; init; } = string.Empty; // subtype: add, remove, rename
     public string? Name { get; set; } // subtype: add
     public string[] Names { get; set; } = []; //subtype:  remove
-    public string OldName { get; set; } // subtype: rename
-    public string NewName { get; set; } // subtype: rename
+    public string? OldName { get; set; } // subtype: rename
+    public string? NewName { get; set; } // subtype: rename
     public Uri? Value { get; set; }// subtypes: add, rename
 
     public EmojiChange CreateSubType() => SubType switch
     {
         SubTypeAdd => new EmojiAdded { Name = Name!, Value = Value! },
         SubTypeRemove => new EmojiRemoved { Names = Names },
-        SubTypeRename => new EmojiRenamed { OldName = OldName, NewName = NewName, Value = Value },
+        SubTypeRename => new EmojiRenamed { OldName = OldName!, NewName = NewName!, Value = Value },
         _ => new UnknownEmojiChange()
     };
 }
@@ -29,7 +29,7 @@ public class EmojiChange();
 public class EmojiAdded : EmojiChange
 {
     public required string Name { get; init; }
-    public Uri Value { get; init; }
+    public required Uri Value { get; init; }
 }
 
 public class EmojiRemoved : EmojiChange
@@ -39,9 +39,9 @@ public class EmojiRemoved : EmojiChange
 
 public class EmojiRenamed : EmojiChange
 {
-    public string OldName { get; set; } // subtype: rename
-    public string NewName { get; set; } // subtype: rename
-    public Uri? Value { get; set; }// subtypes: add, rename
+    public required string OldName { get; init; } // subtype: rename
+    public required string NewName { get; init; } // subtype: rename
+    public required Uri? Value { get; init; }// subtypes: add, rename
 }
 
 public class UnknownEmojiChange() : EmojiChange;