node.js笔记

Posted 2020-08-25 西北望，射天狼

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最近在读<Node入门经典>, 之前没有做笔记, 今天开始把看过自己又写了的代码放这里以免忘记.

express

var express = require(\'express\')
var app = express()

app.get(\'/\', function (req, res) {
  res.send(\'Hello World\')
})
app.listen(3000)

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route

var http = require(\'http\');
var url = require(\'url\');

http.createServer(function(req,res){
	
	var name = url.parse(req.url).pathname;
	if (name === \'/\'){
		res.writeHead(200,{
			\'Content-Type\':\'text/plain\'
		});
		res.end(\'home page\');
	}
	else if (name === \'/about\'){
		res.writeHead(200,{
			\'Content-Type\':\'text/plain\'
		});
		res.end(\'about me\');
	}
	else if (name === \'/redirect\')
	{
		res.writeHead(301,{
		\'location\': \'http://www.baidu.com\'
		});
		res.end();
	}
	else{
		res.writeHead(404,{
			\'Content-Type\':\'text/plain\'
		});
		res.end(\'page not find\');
	}	
	
	
	
}).listen(3000, "127.0.0.1");

console.log(\'server start\');

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socket.io

var app = require(\'express\')();
var http = require(\'http\').Server(app);
var io = require(\'socket.io\')(http);

app.get(\'/\', function(req, res){
  res.sendfile(\'index2.html\');
});

io.on(\'connection\', function(socket){
  console.log(\'a user connected\');
  socket.emit(\'chat message\', {text:\'hi\'});

  socket.on(\'disconnect\', function(){
    console.log(\'user disconnected\');
  });
  
  socket.on(\'chat message\', function(msg){
    console.log(\'message: \' + msg);
  });
});

http.listen(3000, function(){
  console.log(\'listening on *:3000\');
});

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<!doctype html>
<html>
  <head>
    <title>Socket.IO chat</title>    
  </head>
  <body>
    <p id=\'count\'></p>
    <script src="/socket.io/socket.io.js"></script>

    <script>
      var socket = io();
      var count = document.getElementById(\'count\');
      socket.on(\'chat message\', function(data){
        count.innerHTML = data.text;
      });

</script>
  </body>
</html>

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json

var http = require(\'http\');

var obj = {
	name:\'green\',
	sur:\'abcd\'
};
console.log(obj);

var json = JSON.stringify(obj);
console.log(json);

var ori = JSON.parse(json);
console.log(ori);

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spawn

var spawn = require(\'child_process\').spawn;
var ping = spawn(\'ping\', [\'www.baidu.com\']);
ping.stdout.setEncoding(\'utf8\');
ping.stdout.on(\'data\', function(data){
	console.log(data);
});
ping.on(\'exit\', function(code, signal){
	console.log(code,  \' \', signal);
	process.exit(0);
});
setInterval(function(){
	ping.kill(\'SIGINT\');	
},	2000);

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cluster

var cluster = require(\'cluster\');
var http = require(\'http\');
var cpus = 4;
if (cluster.isMaster){
	console.log(\'master start at \' + process.pid);
	
	for (var i = 0; i < cpus; ++i ){
		cluster.fork();		
	}
	cluster.on(\'death\', function(worker){
		console.log(\'die: \' + woker.pid);
		cluster.fork();
	});
}
else{
	console.log(\'worker start \' + process.pid);

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events

var eventEm = require(\'events\').EventEmitter;
var myEvent = new eventEm();

myEvent.on(\'message\', function(data){
	console.log(data);
});

myEvent.on(\'destroy\', function(){
	console.log(\'destroyed\');
});

myEvent.emit(\'message\',\'show message\');
setTimeout(function(){
	myEvent.emit(\'destroy\');
}, 1000);

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stream

var http = require(\'http\');
var fs = require(\'fs\');

http.createServer(function(req,res){
	var mp3 = \'abc.mp3\';
	var stat = fs.statSync(mp3);
	
	res.writeHead(200,
	{
		\'Content-Type\':\'audio/mpeg\',
		\'Content-Length\': stat.size
	});
	var readSteam = fs.createReadStream(mp3);
	readSteam.pipe(res);
	
}).listen(3000, "127.0.0.1");

console.log(\'server start\');

View Code

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