Master Go WebSocket with Gorilla: Build, Test, and Compare Clients

The article introduces the Gorilla WebSocket library, a widely adopted, high‑performance Go implementation that fills functional gaps left by the standard library.

Dependency

Add the library to your project:

github.com/gorilla/websocket v1.4.2

WebSocket Server Development

Unlike the standard library, Gorilla requires an Upgrader to convert an HTTP request into a WebSocket connection. The following snippet creates a simple upgrader:

var upgrader = websocket.Upgrader{
    ReadBufferSize:   1024,
    WriteBufferSize:  1024,
    HandshakeTimeout: 5 * time.Second,
}

A complete server handler reads messages, echoes them back, and logs activity:

func TestWEBs(t *testing.T) {
    upgrader := websocket.Upgrader{ReadBufferSize: 1024, WriteBufferSize: 1024, HandshakeTimeout: 5 * time.Second}
    http.HandleFunc("/websocket", func(w http.ResponseWriter, r *http.Request) {
        conn, _ := upgrader.Upgrade(w, r, nil)
        for {
            msgType, msg, err := conn.ReadMessage()
            if err != nil { return }
            fmt.Printf("%s receive: %s
", conn.RemoteAddr(), string(msg))
            if err = conn.WriteMessage(msgType, msg); err != nil { return }
        }
    })
    http.ListenAndServe(":12345", nil)
}

Client Implementations

Two client examples are provided: a Java client using a custom WebSocketFunClient wrapper, and a Go client that dials the server directly.

package com.funtest.javatest;
import com.funtester.frame.SourceCode;
import com.funtester.socket.WebSocketFunClient;
public class WebSocketT extends SourceCode {
    public static void main(String[] args) {
        WebSocketFunClient instance = WebSocketFunClient.getInstance("ws://localhost:1234/websocket");
        instance.connect();
        instance.send("你好,我是FunTester - Java ,Have Fun ~ Tester ！");
    }
}

// TestWebSocket – Go client
func TestWebSocket(t *testing.T) {
    url := "ws://localhost:1234/websocket"
    c, res, err := websocket.DefaultDialer.Dial(url, nil)
    if err != nil { log.Fatal("连接失败:", err) }
    log.Printf("响应:%s", fmt.Sprint(res))
    defer c.Close()
    done := make(chan struct{})
    err = c.WriteMessage(websocket.TextMessage, []byte("你好,我是FunTester"))
    if err != nil { fmt.Println(err) }
    for {
        _, message, err := c.ReadMessage()
        if err != nil { log.Fatal(err); break }
        log.Printf("收到消息: %s", message)
    }
    <-done
}

Testing

Run the server first, then launch the clients. Sample logs show successful message exchange:

=== RUN   TestWEBs
[::1]:59843 sent: 你好,我是FunTester
127.0.0.1:59902 receive: 你好,我是FunTester - Java ,Have Fun ~ Tester ！

=== RUN   TestWebSocket
2021/11/15 11:47:26 响应:&{101 Switching Protocols ...}
2021/11/15 11:47:26 收到消息: 你好,我是FunTester

Conclusion

The author notes that Go’s WebSocket implementation outperforms Java in connection throughput, handling tens of thousands of connections within minutes, making Go a preferred choice for future WebSocket functionality and performance testing.