Go Gorilla WebSocket
Learn how to use WebSockets in Go with the Gorilla WebSocket library. Includes examples of real-time communication.
Go Gorilla WebSocket
last modified April 11, 2024
In this article we show how to work with websockets using Gorilla WebSocket package.
WebSocket is a computer communications protocol, providing full-duplex communication channels over a single TCP connection. WebSockets are used in highly interactive applications such as games, chats, or stock markets.
The Gorilla WebSocket package provides a complete and tested implementation of the WebSocket protocol.
$ go get github.com/gorilla/websocket
This command installs the package.
Gorilla WebSocket example
In the example, we create a simple websocket server. The client will be a browser that connects to the server with JS code.
main.go
package main
import ( “fmt” “log” “net/http”
"github.com/gorilla/websocket"
)
var upgrader = websocket.Upgrader{ ReadBufferSize: 1024, WriteBufferSize: 1024, }
func main() {
http.HandleFunc("/echo", func(w http.ResponseWriter, r *http.Request) {
conn, err := upgrader.Upgrade(w, r, nil)
if err != nil {
log.Fatal(err)
}
for {
msgType, msg, err := conn.ReadMessage()
if err != nil {
return
}
fmt.Printf("%s sent: %s\n", conn.RemoteAddr(), string(msg))
if err = conn.WriteMessage(msgType, msg); err != nil {
return
}
}
})
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
http.ServeFile(w, r, "index.html")
})
log.Println("Listening...")
log.Fatal(http.ListenAndServe(":8080", nil))
}
The program sets up the websocket endpoint and a static index.html page.
var upgrader = websocket.Upgrader{ ReadBufferSize: 1024, WriteBufferSize: 1024, }
We define buffers for the upgrader. It specifies parameters for upgrading an HTTP connection to a WebSocket connection.
http.HandleFunc("/echo", func(w http.ResponseWriter, r *http.Request) {
We register a handler function for the /echo endpoint.
conn, err := upgrader.Upgrade(w, r, nil)
We upgrade the HTTP server connection to the WebSocket protocol.
for {
msgType, msg, err := conn.ReadMessage()
if err != nil {
return
}
fmt.Printf("%s sent: %s\n", conn.RemoteAddr(), string(msg))
if err = conn.WriteMessage(msgType, msg); err != nil {
return
}
}
We continually listen for any incoming messages sent through that WebSocket connection. We read the message from the client with ReadMessage. The WriteMessage writes the message back to the client.
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) { http.ServeFile(w, r, “index.html”) })
We set up the static HTML home page, from which we connect to the server.
The connection to the websocket endpoint is made from the browser.
index.html
<!DOCTYPE html> <html lang=“en”>
<head> <meta charset=“UTF-8”> <meta name=“viewport” content=“width=device-width, initial-scale=1.0”> <title>Document</title> </head>
<body>
<input id="input" type="text">
<button onclick="send()">Send</button>
<pre id="output"></pre>
<script>
var input = document.getElementById("input");
var output = document.getElementById("output");
var socket = new WebSocket("ws://localhost:8080/echo");
socket.onopen = () => {
output.innerHTML += "connected\n";
};
socket.onmessage = (e) => {
output.innerHTML += `{e.data}\n`;
};
function send() {
socket.send(input.value);
input.value = "";
}
</script>
</body>
</html>
In JS, we use the WebSocket class provides the API for creating and managing a WebSocket connection to a server, as well as for sending and receiving data on the connection.
Source
Gorilla Websocket - Github page
In this article we have worked with websockets using Gorilla WebSocket package.
Author
My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.
List all Go tutorials.
