Using public channels with Golang

Using public channels with Golang

Public channels do not require authentication. Public channels can be used for features without sensitive information, such as these use cases:

• Notify all users with the e-commerce page loaded when a new product goes on sale.
• Live chat similar to YouTube chat.
• Trigger updates for all clients currently viewing a page when it changes.

Frontend

<html>
    <body>
       <h1>Pusher test</h1> 
      <script>
        document.addEventListener('DOMContentLoaded', function() {
            var pusher = new Pusher("RESSONANCE_APP_ID", {
                cluster: "default",
                wsHost: "websocket.ressonance.com",
                wsPort: 443,                  
                wssPort: 443,                 
                forceTLS: true,               
                disableStats: true,            
                enabledTransports: ["ws", "wss"]
            });

            var channel = pusher.subscribe("public-channel");

            channel.bind("new-release", (data) => {
                alert("New release", data.release);
            });
        });
      </script>
      <script src="https://js.pusher.com/8.3.0/pusher.min.js"></script>  
    </body>
</html>

Backend

go get github.com/pusher/pusher-http-go/v5

This is a small Golang example application.

package main

import (
	"log"
	"net/http"

	pusher "github.com/pusher/pusher-http-go/v5"
)

func withCors(next http.HandlerFunc) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Access-Control-Allow-Origin", "*")
		w.Header().Set("Access-Control-Allow-Methods", "GET,POST,OPTIONS")
		w.Header().Set("Access-Control-Allow-Headers", "Content-Type")

		if r.Method == http.MethodOptions {
			w.WriteHeader(http.StatusNoContent)
			return
		}

		next(w, r)
	}
}

func main() {
	client := pusher.Client{
		AppID:  "RESSONANCE_APP_ID",
		Key:    "RESSONANCE_APP_KEY",
		Secret: "RESSONANCE_APP_SECRET",
		Host:   "websocket.ressonance.com",
		Secure: true,
	}

	http.HandleFunc("/send-public-event", withCors(func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodGet {
			http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
			return
		}

		err := client.Trigger("public-channel", "new-release", map[string]string{"release": "hello world"})
		if err != nil {
			http.Error(w, "Failed to send event.", http.StatusInternalServerError)
			return
		}

		w.Write([]byte("Event sent!"))
	}))

	log.Fatal(http.ListenAndServe(":8080", nil))
}