页面脚本可以与共享型web worker通信,然而,与专用型web worker(使用了一个隐式的端口通信)稍微有点不同的是,通信是显式的通过使用一个端口(port)对象并附加上一个消息事件处理程序来进行的。
在收到web worker脚本的首个消息之后,共享型web worker把一个事件处理程序附加到激活的端口上。一般情况下,处理程序会运行自己的postMessage()方法来把一个消息返回给调用代码,接着端口的start()方法生成一个有效的消息进程。
看网上能找到的的唯一个例子:创建一个共享线程用于接收从不同连接发送过来的指令,然后实现自己的指令处理逻辑,指令处理完成后将结果返回到各个不同的连接用户。
HTML代码:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Shared worker example: how to use shared worker in HTML5</title>
<script>
var worker = new SharedWorker('sharedworker.js');
var log = document.getElementById('response_from_worker');
worker.port.addEventListener('message', function(e) {
//log the response data in web page
log.textContent =e.data;
}, false);
worker.port.start();
worker.port.postMessage('ping from user web page..');
//following method will send user input to sharedworker
function postMessageToSharedWorker(input)
{
//define a json object to construct the request
var instructions={instruction:input.value};
worker.port.postMessage(instructions);
}
</script>
</head>
<body onload=''>
<output id='response_from_worker'>
Shared worker example: how to use shared worker in HTML5
</output>
send instructions to shared worker:
<input type="text" autofocus oninput="postMessageToSharedWorker(this);return false;">
</input>
</body>
</html>
脚本文件代码:
// 创建一个共享线程用于接收从不同连接发送过来的指令,指令处理完成后将结果返回到各个不同的连接用户。
var connect_number = 0;
onconnect = function(e) {
connect_number =connect_number+ 1;
//get the first port here
var port = e.ports[0];
port.postMessage('A new connection! The current connection number is '
+ connect_number);
port.onmessage = function(e) {
//get instructions from requester
var instruction=e.data.instruction;
var results=execute_instruction(instruction);
port.postMessage('Request: '+instruction+' Response '+results
+' from shared worker...');
};
};
/*
* this function will be used to execute the instructions send from requester
* @param instruction
* @return
*/
function execute_instruction(instruction)
{
var result_value;
//implement your logic here
//execute the instruction...
return result_value;
}