前端调用websocket的3种不同写法
一、前言
- 我们知道
websocket
是一个ws://***
连接,我们可以调用网站 websocket.org 的ws://echo.websocket.org
作为 前端调用服务端
的地址 只是 3 种 [ 写法 ],不是 3 种 [ 方法 ]
二、使用
写法1
请参考我这一篇Go gorilla websocket 小试牛刀,使用其中的 client.html
文件,修改服务端地址为 ws://echo.websocket.org
即可。
效果如图
代码如下
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>websocket实现消息推送</title>
<script>
window.addEventListener("load",function (event) {
let output = document.getElementById("output")
let input = document.getElementById("input")
let ws
let print = function (message) {
let d=document.createElement("div")
d.innerHTML = message
output.appendChild(d)
}
document.getElementById("open").onclick = function (event) {
if(ws){
return false
}
ws = new WebSocket("ws://echo.websocket.org");
ws.onopen = function (event) {
print("打开")
}
ws.onclose = function (event) {
print("关闭")
ws = null
}
ws.onmessage = function (event) {
print("响应:"+event.data)
}
ws.onerror = function (event) {
print("错误:"+event.data)
}
return false
}
document.getElementById("send").onclick = function (event) {
if(!ws){
return false
}
print("发送:"+input.value)
ws.send(input.value)
return false
}
document.getElementById("close").onclick = function (event) {
ws.close()
return false
}
})
</script>
</head>
<body>
<table>
<tr>
<td valign="top" width="50%">
<p>
点击:<br>
“打开”和服务端创建一个连接。<br>
"发送"发送一个消息给服务端。<br>
"关闭"去关闭连接.<br>
你可以改变消息Message并且发送多次.<br>
</p>
<form>
<button id="open">打开</button>
<button id="close">关闭</button><br>
<input id="input" type="text" value="Websocket —— Go">
<button id="send">发送</button><br>
</form>
</td>
<td valign="top" width="50%">
<div id="output"></div>
</td>
</tr>
</table>
</body>
</html>
写法2
使用 http://www.websocket.org/echo.html中的demo,就在这个页面下面。
效果如图
代码如下
<!DOCTYPE html>
<meta charset="utf-8" />
<title>WebSocket Test</title>
<script language="javascript" type="text/javascript">
var wsUri = "wss://echo.websocket.org/";
var output;
function init()
{
output = document.getElementById("output");
testWebSocket();
}
function testWebSocket()
{
websocket = new WebSocket(wsUri);
websocket.onopen = function(evt) { onOpen(evt) };
websocket.onclose = function(evt) { onClose(evt) };
websocket.onmessage = function(evt) { onMessage(evt) };
websocket.onerror = function(evt) { onError(evt) };
}
function onOpen(evt)
{
writeToScreen("CONNECTED");
doSend("WebSocket rocks");
}
function onClose(evt)
{
writeToScreen("DISCONNECTED");
}
function onMessage(evt)
{
writeToScreen('<span style="color: blue;">RESPONSE: ' + evt.data+'</span>');
websocket.close();
}
function onError(evt)
{
writeToScreen('<span style="color: red;">ERROR:</span> ' + evt.data);
}
function doSend(message)
{
writeToScreen("SENT: " + message);
websocket.send(message);
}
function writeToScreen(message)
{
var pre = document.createElement("p");
pre.style.wordWrap = "break-word";
pre.innerHTML = message;
output.appendChild(pre);
}
window.addEventListener("load", init, false);
</script>
<h2>WebSocket Test</h2>
<div id="output"></div>
写法3
自己写一个,使用try{}catch(){}捕获异常
效果如图
代码如下
<!DOCTYPE html>
<meta charset="utf-8" />
<title>WebSocket Test</title>
<h2>WebSocket 连接测试</h2>
<div id="output"></div>
<script language="javascript" type="text/javascript">
//消息打印
var output = document.getElementById("output");
var print = function (message) {
var d=document.createElement("div")
d.innerHTML = message
output.appendChild(d)
};
//websocket连接
var wsUri = "wss://echo.websocket.org/";
testWebSocket(wsUri);
function testWebSocket(wsUri){
var webSocket = new WebSocket(wsUri);
//接收消息
webSocket.onmessage = function(event){
//捕获异常
try {
var obj = JSON.parse(event.data);
if (typeof obj == 'object' && obj) {
print(obj);
console.log(obj);
}
} catch (e) {
print('catch-error' + event.data + ' json解析异常 ' + e);
console.log('catch-error' + event.data + ' json解析异常 ' + e);
}
}.bind(this);
//连接成功
webSocket.onopen = function () {
print('connect-success');
console.log('connect-success')
};
//连接关闭
webSocket.onclose = function (event) {
print('connect-close:' + event.data);
console.log('connect-close:' + event.data)
};
//连接异常
webSocket.onerror = function (event) {
print('connect-error:' + event.data);
console.log('connect-error:' + event.data);
}
}
</script>