yudai/gotty · error

Method not allowed

Error message

Method not allowed

What it means

Plain 405 response from the WS handler guard: the HTTP method of the upgrade request is not GET, which is required by the websocket handshake, so the connection is rejected before any upgrade or auth is attempted.

Source

Thrown at server/handlers.go:64

				closeReason, r.RemoteAddr, num, server.options.MaxConnection,
			)

			if server.options.Once {
				cancel()
			}
		}()

		if int64(server.options.MaxConnection) != 0 {
			if num > server.options.MaxConnection {
				closeReason = "exceeding max number of connections"
				return
			}
		}

		log.Printf("New client connected: %s, connections: %d/%d", r.RemoteAddr, num, server.options.MaxConnection)

		if r.Method != "GET" {
			http.Error(w, "Method not allowed", 405)
			return
		}

		conn, err := server.upgrader.Upgrade(w, r, nil)
		if err != nil {
			closeReason = err.Error()
			return
		}
		defer conn.Close()

		err = server.processWSConn(ctx, conn)

		switch err {
		case ctx.Err():
			closeReason = "cancelation"
		case webtty.ErrSlaveClosed:
			closeReason = server.factory.Name()
		case webtty.ErrMasterClosed:

View on GitHub (pinned to a080c85cbc)

Solutions

1. Send websocket upgrade requests as GET only
2. Fix client code accidentally POST/PUT-ing to the ws URL
3. Check for proxies rewriting the method in front of the server

When it happens

Trigger: Thrown at server/handlers.go:64 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of yudai/gotty@a080c85cbc (2026-09-02). Data as JSON: /api/errors/cefba20e2341e88d. Report an issue: GitHub.