文件操作
- 文件系统的操作
*fs.readFile(filename, [options], callback)
*fs.writeFile(filename, data, [options], callback)
//同步
fs.writeFileSync('data/' + dist, fs.readFileSync(src));
//异步
fs.readFile(src, function (err, data) {
if (err) {
throw err;
} else {
fs.writeFile(dist, data, function (err) {
if (err) throw err;
})
}
});
- 数据流操作
fs.createReadStream(path, [options]),fs.createWriteStream(path, [options])
//使用pipe
fs.createReadStream(src).pipe(fs.createWriteStream('./data/' + dist));
//
var rs = fs.createReadStream(src);
var ws = fs.createWriteStream(dist);
rs.on('data', function (chunk) {
if (ws.write(chunk) === false) {
//判断写入还是缓存
rs.pause();
}
});
rs.on('end', function () {
ws.end();
});
ws.on('drain', function () {
//已经写入的话继续
rs.resume();
});
fs内置模块常用api
- 文件属性读写
*fs.stat//获取文件信息
*fs.chown//更改文件所有权
*fs.chmod//改写文件的读写权限 - 文件内容读写
*fs.readFile
*fs.readdir
*fs,writeFile
*fs.mkdir - 底层文件操作
*fs.open
*fs.read
*fs.close
*fs.unlink
读取文件
- 使用
fs.readStream读取文件；
var http = require('http');
var path = require('path');
var fs = require('fs');
var url = require('url');
var mimeTypes = {
'.js' : 'text/javascript',
'.html': 'text/html',
'.css' : 'text/css'
};
//设置白名单
var whitelist = [
'/index.html',
'/style.css',
'/script.js'
];
var cache = {
store: {},
maxSize : 26214400, //(bytes) 25mb
maxAge: 5400 * 1000, //(ms) 1 and a half hours
clearnAfter: 7200 * 1000,//(ms) two hours
cleanedAt: 0, //to be set dynamically
clean: function (now) {
if (now - this.cleanAfter > this.cleanedAt) {
this.cleanedAt = now;
var maxAge = this.maxAge;
Object.keys(this.store).forEach(function (file) {
if (now > this.store[file].timestamp + maxAge) {
delete this.store[file];
}
}.bind(this));
}
}
};
http.createServer(function (req, res) {
if (req.url === '/favicon.ico') return;
var lookup = url.parse(decodeURI(req.url)).pathname;
lookup = path.normalize(lookup);
lookup = (lookup === '/') ? '/index.html' : lookup;
if (whitelist.indexOf(lookup) === -1) {
res.writeHead(404);
return res.end('Page Not Found!');
}
var f = './public' + lookup;
console.log(f);
fs.exists(f, function (exists) {
if (exists) {
var headers = {'Content-Type': mimeTypes[path.extname(lookup)]};
if(cache.store[f]) {
res.writeHead(200, headers);
return res.end(cache.store[f].content);
}
var s = fs.createReadStream(f).once('open', function () {
res.writeHead(200, headers);
this.pipe(res);
}).once('err', function (err) {
console.log('err:', e);
res.writeHead(500);
return res.end('Server Error!');
});
//对输出流保存cache处理;设置buffer需要大小,使用fs.stat获取
return fs.stat(f, function (err, stats) {
if (stats.size < cache.maxSize) {
var bufferOffset = 0;
cache.store[f] = {content: new Buffer(stats.size), timestamp: Date.now()};
s.on('data', function (chunk) {
chunk.copy(cache.store[f].content, bufferOffset);
bufferOffset += chunk.length; //大小设置
})
}
});
}
res.writeHead(404);
return res.end('Not find Source!');
});
//清除超出时间的缓存
cache.clean(Date.now());
}).listen(3000);
- 使用
fs.readFile读取文件
var http = require('http');
var path = require('path');
var fs = require('fs');
var mimeTypes = {
'.js' : 'text/javascript',
'.html': 'text/html',
'.css' : 'text/css'
};
var cache = {};
function cacheAndDeliver (f, cb) {
fs.stat(f, function (err, stats) {
if (err) return console.log('Error: ',err);
var lastChanged = Date.parse(stats.ctime);
var isUpdated = cache[f] && lastChanged > cache[f].timestamp;
if (!cache[f] || isUpdated) {
fs.readFile(f, function (err, data) {
if (!err) cache[f] = {content: data, timestamp: Date.now()}; //store a Unix time stamp
cb(err, data);
});
return;
}
console.log('loading ' + f + ' from cache');
return cb(null, cache[f].content);
})
};
http.createServer(function (req, res) {
if (req.url === '/favicon.ico') return;
var lookup = path.basename(decodeURI(req.url)) || 'index.html';
var f = './public/' + lookup;
fs.exists(f, function (exists) {
if (exists) {
cacheAndDeliver(f, function (err, data) {
if (err) {
res.writeHead(500);
res.end('Server Error!');
return;
}
var headers = {'Content-Type': mimeTypes[path.extname(lookup)]};
res.writeHead(200, headers);
res.end(data);
});
return; //注意return的位置
}
res.writeHead(404);
return res.end('Not find Source!');
})
}).listen(3000);
路径处理
-
url路径处理:
*url.parse(req.url).pathname;url.parse(req.url, true).query -
文件路径处理:
*path.join(__dirname, pathname);
path.dirname('/foo/bar/baz/asdf/quux') '/foo/bar/baz/asdf'
//
path.basename('/foo/bar/baz/asdf/quux.html') 'quux.html'
path.basename('/foo/bar/baz/asdf/quux.html', '.html') 'quux'
//
path.extname('index.coffee.md') '.md'
path.extname('index.') '.'
path.extname('index') ''
path.extname('.index') ''
- 递归一个文件夹例子
function travelS(dir, cb) {
fs.readdirSync(dir).forEach(function (file) {
var pathname = path.join(dir, file);
if (fs.statSync(pathname).isDirectory()) {
travelS (pathname, callback);
} else {
callback(pathname);
}
})
};
process
事件
process.on('exit', function(){});process.on('uncaughtException', function(){});- 信号事件:
:SIGINT,SIGUSR1...- 一个简单的方式发送SIGINT信号的方法是:control-c
方法
process.uptime(): Node的运行时间;process.nextTick(func): 将函数放到后面运行;process.cwd(): 显示当前文件夹目录；process.exit(code): 退出进程，内部调用进程的exit事件,code：0表示成功退出，1表示失败退出;process.kill(pid[, signal])#: 退出进程, 触发第二参数，为SIGINT,SIGHUP
属性
process.env: 运行环境参数;process.stdin: 输入流;process.stdin.resume();: 开启输入流,调用一次后程序不会马上停止;process.stdin.setEncoding('utf8')
process.stdout: 输出流;
process.stdin.resume();
process.stdin.pipe(process.stdout);
process.stderr: 错误流；process.pid: 进程的pid
数据交互
上传数据常用类型
application/x-www-form-urlencoded;application/json;application/xml;multipart/form-data;
JSONP
//client
var who = 'ryan';
function cb(o) {
alert(o.name + ' : ' + o.description);
}
var s = document.createElement('script');
s.src = 'http://localhost:3000/?callback=cb&who=' + who;
document.getElementsByTagName("head")[0].appendChild(s);
//server
var profiles = require("./profiles.json");
.....
if(cb && who) {
profile = cb + '(' + JSON.stringify(profiles[who]) + ')';
return res.end(profile);
}
上传文件例子
var http = require('http');
var formiable = require('formidable');
var fs = require('fs');
var form = require('fs').readFileSync('./public/form-upload.html');
http.createServer(function (req, res) {
if (req.method === 'GET') {
res.writeHead(200, {'Content-Type': 'text/html'});;
return res.end(form);
}
if (req.method === 'POST') {
var incoming = new formiable.IncomingForm();
var f = './uploads';
incoming.uploadDir = f;
form.multiples = true;
!fs.existsSync(f) && fs.mkdir(process.env.PWD + '/uploads'); //使用绝对路径创建文件夹
incoming.on('fileBegin', function (field, file) {
if(file.name) file.path += "-" + file.name;
}).on('file', function (field, file) {
if (file.size == 0) return fs.unlinkSync(file.path);
res.write(file.name + ' received
');
}).on('field', function (field, value) {
res.write(field + ' : ' + value + '
');
}).on('end', function () {
res.end('All files received!');
}).parse(req, function (err, fields, files) {
});
}
if(req.method === 'PUT') {
var f = './uploads';
!fs.existsSync(f) && fs.mkdir(f);
var fileData = new Buffer(+req.headers['content-length']);
var bufferOffset = 0;
req.on('data', function (chunk) {
chunk.copy(fileData, bufferOffset); //连接Buffer对象的正确方法
bufferOffset += chunk.length;
}).on('end', function () {
var rand = (Math.random()*Math.random()).toString(16).replace('.','');
var to = 'uploads/' + rand + "-" + req.headers['x-uploadedfilename'];
fs.writeFile(to, fileData, function (err) {
if (err) throw err;
console.log('Saved file to ' + to);
})
})
}
}).listen(3000);