Response does not implement http.Hijacker

Question

I\'m using Go and trying to implement WebSocket in my project. while implementing this. I get "WebSocket: response does not implement HTTP.Hijacker" error. I\'m ne

Answer 1

To cite the docs on http.Hijacker:

~$ go doc http.Hijacker

package http // import "net/http"

type Hijacker interface {
  // Hijack lets the caller take over the connection.
  // After a call to Hijack the HTTP server library
  // will not do anything else with the connection.
  //
  // It becomes the caller's responsibility to manage
  // and close the connection.
  //
  // The returned net.Conn may have read or write deadlines
  // already set, depending on the configuration of the
  // Server. It is the caller's responsibility to set
  // or clear those deadlines as needed.
  //
  // The returned bufio.Reader may contain unprocessed buffered
  // data from the client.
  //
  // After a call to Hijack, the original Request.Body must not
  // be used. The original Request's Context remains valid and
  // is not canceled until the Request's ServeHTTP method
  // returns.
  Hijack() (net.Conn, *bufio.ReadWriter, error)
}

The Hijacker interface is implemented by ResponseWriters that allow an HTTP handler to take over the connection.

The default ResponseWriter for HTTP/1.x connections supports Hijacker, but HTTP/2 connections intentionally do not. ResponseWriter wrappers may also not support Hijacker. Handlers should always test for this ability at runtime.

So, I see several possibilities for your problem to happen:

• You're trying to turn an HTTP/2 connection to a Websocket.
• You're using some "middleware" which wraps whatever object the stock net/http package passes to your handler as net/http.ResponseWriter with something which does not bother to implement the proper Hijack method to support the net/http.Hijacker interface.