nodejs培训课程之压缩与解压缩

作者:日期:2016-08-29 16:26:44 点击:222

压缩与解压缩处理

可以使用zlib模块进行压缩及解压缩处理,压缩文件以后可以减少体积,加快传输速度和节约带宽 代码

压缩对象

压缩和解压缩对象都是一个可读可写流

方法 说明
zlib.createGzip 返回Gzip流对象,使用Gzip算法对数据进行压缩处理
zlib.createGunzip 返回Gzip流对象,使用Gzip算法对数据进行压缩处理
zlib.createDeflate 返回Deflate流对象,使用Deflate算法对数据进行压缩处理
zlib.createInflate 返回Deflate流对象,使用Deflate算法对数据进行压缩处理

压缩和解压缩

var zlib = require('zlib'); var fs = require('fs');  function zip(src) {     var gzip = zlib.createGzip();     var inputStream = fs.createReadStream(src);     var outputStream = fs.createWriteStream(src+'.gz');     inputStream.pipe(gzip).pipe(outputStream); } zip('source.txt');  function gunzip(src){     var gunzip = zlib.createGunzip();     var inputStream = fs.createReadStream(src);     var outputStream = fs.createWriteStream(src.slice(0,-3));     inputStream.pipe(gunzip).pipe(outputStream); }   gunzip('source.txt.gz'); 

在http中的应用

var zlib = require('zlib'); var fs = require('fs'); var http = require('http'); http.createServer(function (request, response) {     var raw = fs.createReadStream('.' + request.url);     var acceptEncoding = request.headers['accept-encoding'];     if (!acceptEncoding) {         acceptEncoding = '';     }     if (acceptEncoding.match(/\bdeflate\b/)) {         response.setHeader('Content-Encoding','deflate');         raw.pipe(zlib.createDeflate()).pipe(response);     } else if (acceptEncoding.match(/\bgzip\b/)) {         response.setHeader('Content-Encoding','gzip');         raw.pipe(zlib.createGzip()).pipe(response);     } else {         raw.pipe(response);     } }).listen(9090) 
var zlib = require('zlib'); var fs = require('fs'); var http = require('http');  var request = http.get({     host: 'localhost',     path: '/index.html',     port: 9090,     headers: {         'accept-encoding': 'gzip,deflate'     } })  request.on('response', function (response) {     var output = fs.createWriteStream('test.txt');     switch (response.headers['content-encoding']) {         case 'gzip':             response.pipe(zlib.createGunzip()).pipe(output);             break;         case 'deflate':             response.pipe(zlib.createInflate()).pipe(output);             break;         default:             response.pipe(output);             break;     } }); request.end(); 

方法调用

var zlib = require('zlib'); var fs = require('fs');  var out = fs.createWriteStream('input.log'); var input = 'input'; zlib.gzip(input, function (err, buffer) {     if (!err) {         zlib.unzip(buffer, function (err, buffer) {             if (!err) {                 console.log(buffer.toString());                 out.end(buffer);             }         })     } }) 

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