"Error Processing Request" before attempting login, with "Value cannot be null" in the logs

[alexander-bauer]

Describe the bug
Attempting to log in with SSO causes an opaque error that I am unsure how to troubleshoot further.

To Reproduce
Steps to reproduce the behavior:

After configuring SSO from the admin panel, I opened another window to attempt to log in with a user (that is not yet created in Jellyfin), at https://jellyfin.<mydomain>/sso/OID/r/keycloak.

Expected behavior
Redirect to Keycloak, log in, redirect back to Jellyfin WebUI.

Configuration

{
  "keycloak": {
    "OidEndpoint": "https://keycloak.<domain>/realms/<realm>",
    "OidClientId": "jellyfin",
    "OidSecret": "<redacted>",
    "Enabled": true,
    "EnableAuthorization": true,
    "EnableAllFolders": true,
    "EnabledFolders": [],
    "AdminRoles": [
      "jellyfin-admin"
    ],
    "Roles": [
      "jellyfin-user"
    ],
    "EnableFolderRoles": false,
    "FolderRoleMapping": [],
    "RoleClaim": "resource_access.jellyfin.roles",
    "OidScopes": [
      "roles"
    ],
    "DefaultProvider": "Jellyfin.Server.Implementations.Users.DefaultAuthenticationProvider",
    "CanonicalLinks": {}
  }
}

Versions (please complete the following information):

• OS: Kubernetes on K3OS
• Browser: Firefox
• Jellyfin Version: 10.8.4
• Plugin Version: 3.4.0.0

Logs

This the message I see in the Jellyfin pod logs.

[23:26:15] [INF] [8] Jellyfin.Plugin.SSO_Auth.Api.SSOController: SSO Controller initialized
[23:26:15] [ERR] [8] Jellyfin.Server.Middleware.ExceptionMiddleware: Error processing request. URL GET /sso/OID/r/keycloak.
System.ArgumentNullException: Value cannot be null. (Parameter 'key')
   at System.Collections.Generic.Dictionary`2.FindValue(TKey key)
   at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
   at Jellyfin.Plugin.SSO_Auth.Api.SSOController.OidPost(String provider, String state)
   at lambda_method586(Closure , Object , Object[] )
   at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.SyncActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeActionMethodAsync()
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeNextActionFilterAsync()
--- End of stack trace from previous location ---
   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()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextResourceFilter>g__Awaited|25_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()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
   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 Jellyfin.Server.Middleware.ServerStartupMessageMiddleware.Invoke(HttpContext httpContext, IServerApplicationHost serverApplicationHost, ILocalizationManager localizationManager)
   at Jellyfin.Server.Middleware.WebSocketHandlerMiddleware.Invoke(HttpContext httpContext, IWebSocketManager webSocketManager)
   at Jellyfin.Server.Middleware.IpBasedAccessValidationMiddleware.Invoke(HttpContext httpContext, INetworkManager networkManager)
   at Jellyfin.Server.Middleware.LanFilteringMiddleware.Invoke(HttpContext httpContext, INetworkManager networkManager, IServerConfigurationManager serverConfigurationManager)
   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
   at Jellyfin.Server.Middleware.QueryStringDecodingMiddleware.Invoke(HttpContext httpContext)
   at Swashbuckle.AspNetCore.ReDoc.ReDocMiddleware.Invoke(HttpContext httpContext)
   at Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke(HttpContext httpContext)
   at Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider)
   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
   at Jellyfin.Server.Middleware.RobotsRedirectionMiddleware.Invoke(HttpContext httpContext)
   at Jellyfin.Server.Middleware.LegacyEmbyRouteRewriteMiddleware.Invoke(HttpContext httpContext)
   at Microsoft.AspNetCore.ResponseCompression.ResponseCompressionMiddleware.InvokeCore(HttpContext context)
   at Jellyfin.Server.Middleware.ResponseTimeMiddleware.Invoke(HttpContext context, IServerConfigurationManager serverConfigurationManager)
   at Jellyfin.Server.Middleware.ExceptionMiddleware.Invoke(HttpContext context)

[alexander-bauer]

Oops. I was navigating to /sso/OID/r/keycloak, but I should've been going to /sso/OID/p/keycloak. The r is, I would guess, for "response".

I hope this issue helps others spot the same mistake.

[9p4]

See #49

Since it seems systemic, I might change it so it's not a one-character path (and allow for the old paths to still work).

[9p4]

Closing in favour of #84