Websocket

Websocket is a http handler for Go, which initiates websocket connections.

Copyright (C) 2019 Jochen Voss

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

Installation

This package can be installed using the go get command:

go get seehuhn.de/go/websocket

Usage

Documentation is available via the package's online help, either on godoc.org or on the command line:

go doc -all seehuhn.de/go/websocket

For demonstation, here is a simple echo server. To install the handler at a given URL, use a websocket.Handler object:

func main() {
        websocketHandler := &websocket.Handler{
                Handle: echo,
        }
        http.Handle("/", websocketHandler)
        log.Fatal(http.ListenAndServe(":8080", nil))
}

The function echo() will be called every time a client makes a connection:

func echo(conn *websocket.Conn) {
        defer conn.Close(websocket.StatusOK, "")

        for {
                tp, r, err := conn.ReceiveMessage()
                if err != nil {
                        break
                }

                w, err := conn.SendMessage(tp)
                if err != nil {
                        // We still need to read the complete message, so that the
                        // next read doesn't block.
                        io.Copy(ioutil.Discard, r)
                        break
                }

                _, err = io.Copy(w, r)
                if err != nil {
                        io.Copy(ioutil.Discard, r)
                }

                w.Close()
        }
}