client.go

Documentation: github.com/gorilla/websocket/examples/echo

     1  // Copyright 2015 The Gorilla WebSocket Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build ignore
     6  // +build ignore
     7  
     8  package main
     9  
    10  import (
    11  	"flag"
    12  	"log"
    13  	"net/url"
    14  	"os"
    15  	"os/signal"
    16  	"time"
    17  
    18  	"github.com/gorilla/websocket"
    19  )
    20  
    21  var addr = flag.String("addr", "localhost:8080", "http service address")
    22  
    23  func main() {
    24  	flag.Parse()
    25  	log.SetFlags(0)
    26  
    27  	interrupt := make(chan os.Signal, 1)
    28  	signal.Notify(interrupt, os.Interrupt)
    29  
    30  	u := url.URL{Scheme: "ws", Host: *addr, Path: "/echo"}
    31  	log.Printf("connecting to %s", u.String())
    32  
    33  	c, _, err := websocket.DefaultDialer.Dial(u.String(), nil)
    34  	if err != nil {
    35  		log.Fatal("dial:", err)
    36  	}
    37  	defer c.Close()
    38  
    39  	done := make(chan struct{})
    40  
    41  	go func() {
    42  		defer close(done)
    43  		for {
    44  			_, message, err := c.ReadMessage()
    45  			if err != nil {
    46  				log.Println("read:", err)
    47  				return
    48  			}
    49  			log.Printf("recv: %s", message)
    50  		}
    51  	}()
    52  
    53  	ticker := time.NewTicker(time.Second)
    54  	defer ticker.Stop()
    55  
    56  	for {
    57  		select {
    58  		case <-done:
    59  			return
    60  		case t := <-ticker.C:
    61  			err := c.WriteMessage(websocket.TextMessage, []byte(t.String()))
    62  			if err != nil {
    63  				log.Println("write:", err)
    64  				return
    65  			}
    66  		case <-interrupt:
    67  			log.Println("interrupt")
    68  
    69  			// Cleanly close the connection by sending a close message and then
    70  			// waiting (with timeout) for the server to close the connection.
    71  			err := c.WriteMessage(websocket.CloseMessage, websocket.FormatCloseMessage(websocket.CloseNormalClosure, ""))
    72  			if err != nil {
    73  				log.Println("write close:", err)
    74  				return
    75  			}
    76  			select {
    77  			case <-done:
    78  			case <-time.After(time.Second):
    79  			}
    80  			return
    81  		}
    82  	}
    83  }
    84
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