System.Collections.Generic.KeyNotFoundException: The given key 'CONNECT' was not present in the dictionary.

[voroninp]

I want to create a WebSocket endpoint.
If I use just [Route] attribute, Swagger throws an error.

Currently ASP.NET does not provide [HttpConnect] attribute., so I had to declare it myself:

public sealed class HttpConnectAttribute : HttpMethodAttribute
{
    private static readonly string[] _httpMethods = ["CONNECT"];

    public HttpConnectAttribute() : base(_httpMethods)
    {
    }

    public HttpConnectAttribute(string template) : base(_httpMethods, template)
    {
    }
}

And after I applied it to the method, swagger throws:

System.Collections.Generic.KeyNotFoundException: The given key 'CONNECT' was not present in the dictionary.
   at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GenerateOperations(IEnumerable`1 apiDescriptions, SchemaRepository schemaRepository)
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GeneratePaths(IEnumerable`1 apiDescriptions, SchemaRepository schemaRepository)
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GetSwaggerDocumentWithoutFilters(String documentName, String host, String basePath)
   at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GetSwaggerAsync(String documentName, String host, String basePath)
   at Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider)
   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddlewareImpl.Invoke(HttpContext context)

I had to exclude that endpoint from the docs: [ApiExplorerSettings(IgnoreApi = true)]

1. How do I add support for 'CONNECT' to Swagger docs?
2. Is there any WebSocket support at all?

[github-actions]

This issue is stale because it has been open for 60 days with no activity. It will be automatically closed in 14 days if no further updates are made.

[martincostello]

Looks like we just need to update this dictionary (and make it not throw if there's a custom method or some future other one we've missed added):

Swashbuckle.AspNetCore/src/Swashbuckle.AspNetCore.SwaggerGen/SwaggerGenerator/SwaggerGenerator.cs

Lines 608 to 618 in 830c5a6

	private static readonly Dictionary<string, OperationType> OperationTypeMap = new Dictionary<string, OperationType>
	{
	{ "GET", OperationType.Get },
	{ "PUT", OperationType.Put },
	{ "POST", OperationType.Post },
	{ "DELETE", OperationType.Delete },
	{ "OPTIONS", OperationType.Options },
	{ "HEAD", OperationType.Head },
	{ "PATCH", OperationType.Patch },
	{ "TRACE", OperationType.Trace }
	};

[martincostello]

See #2600 for supporting CONNECT and other custom HTTP methods.