Inbox URL not following configuration / losing trailing slash

[Terrance]

I'm trying to use BirdsiteLive alongside Takahe, but I'm finding that posts are being sent to /inbox instead of /inbox/ and are therefore being rejected by the server.¹

In the database I can see the correct URL:

birdsitelive=> select * from followers;
-[ RECORD 1 ]--------+--------------------------------------------------
id                   | 12
followings           | {1}
followingssyncstatus | {"1": -1}
acct                 | <user>
host                 | <domain>
inboxroute           | /inbox/
sharedinboxroute     | /inbox/
actorid              | https://<domain>/@<user>@<domain>/
postingerrorcount    | 0

But in the logs at follow time:

info: System.Net.Http.HttpClient.Default.LogicalHandler[100]
      Start processing HTTP request GET https://<domain>/@<user>@<domain>/
info: System.Net.Http.HttpClient.Default.ClientHandler[100]
      Sending HTTP request GET https://<domain>/@<user>@<domain>/
info: System.Net.Http.HttpClient.Default.ClientHandler[101]
      Received HTTP response headers after 8.4817ms - 200
info: System.Net.Http.HttpClient.Default.LogicalHandler[101]
      End processing HTTP request after 8.6428ms - 200
info: System.Net.Http.HttpClient.Default.LogicalHandler[100]
      Start processing HTTP request POST https://<domain>/inbox
info: System.Net.Http.HttpClient.Default.ClientHandler[100]
      Sending HTTP request POST https://<domain>/inbox
info: System.Net.Http.HttpClient.Default.ClientHandler[101]
      Received HTTP response headers after 47.6333ms - 500
info: System.Net.Http.HttpClient.Default.LogicalHandler[101]
      End processing HTTP request after 47.7498ms - 500
fail: Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware[1]
      An unhandled exception has occurred while executing the request.
System.Net.Http.HttpRequestException: Response status code does not indicate success: 500 (Internal Server Error).
   at System.Net.Http.HttpResponseMessage.EnsureSuccessStatusCode()
   at BirdsiteLive.Domain.ActivityPubService.PostDataAsync[T](T data, String targetHost, String actorUrl, String inbox) in /home/user/pkgbuild/birdsitelive/src/birdsitelive/src/BirdsiteLive.Domain/ActivityPubService.cs:line 173
   at BirdsiteLive.Domain.UserService.SendAcceptFollowAsync(ActivityFollow activity, String followerHost) in /home/user/pkgbuild/birdsitelive/src/birdsitelive/src/BirdsiteLive.Domain/UserService.cs:line 210
   at BirdsiteLive.Domain.UserService.FollowRequestedAsync(String signature, String method, String path, String queryString, Dictionary`2 requestHeaders, ActivityFollow activity, String body) in /home/user/pkgbuild/birdsitelive/src/birdsitelive/src/BirdsiteLive.Domain/UserService.cs:line 186
   at BirdsiteLive.Controllers.UsersController.Inbox() in /home/user/pkgbuild/birdsitelive/src/birdsitelive/src/BirdsiteLive/Controllers/UsersController.cs:line 202
   at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.TaskOfIActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeActionMethodAsync>g__Awaited|12_0(ControllerActionInvoker invoker, ValueTask`1 actionResultValueTask)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeNextActionFilterAsync>g__Awaited|10_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeInnerFilterAsync>g__Awaited|13_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResourceFilter>g__Awaited|24_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeFilterPipelineAsync>g__Awaited|19_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
   at Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.<Invoke>g__Awaited|6_0(ExceptionHandlerMiddleware middleware, HttpContext context, Task task)

Note that it's POSTing to /inbox despite what's in the follower database record.

Footnotes

1. This is a Python/Django app which enforces trailing slashes: RuntimeError: You called this URL via POST, but the URL doesn't end in a slash and you have APPEND_SLASH set. Django can't redirect to the slash URL while maintaining POST data. ↩