Node.js实现压缩与解压数据
作者：社会主义接班人
Node.js中提供了一个很好的库Zlib来压缩解压数据。
一、压缩缓冲区
Zlib中有下面几个函数方便解压缩缓冲区.
- gzip/gunzip：标准gzip压缩.
- deflate/inflate：基于Huffman编码的标准deflate压缩算法。
- deflateRaw/inflateRaw：针对原始缓冲区的deflate压缩算法。
它们的函数都是function(buffer,callback).
var zlib = require("zlib");
var input = '...............text...............';
zlib.deflate(input, function(err, buffer) {
if (!err) {
console.log("deflate (%s): ", buffer.length, buffer.toString('base64'));
zlib.inflate(buffer, function(err, buffer) {
if (!err) {
console.log("inflate (%s): ", buffer.length, buffer.toString());
}
});
zlib.unzip(buffer, function(err, buffer) {
if (!err) {
console.log("unzip deflate (%s): ", buffer.length, buffer.toString());
}
});
}
});
zlib.deflateRaw(input, function(err, buffer) {
if (!err) {
console.log("deflateRaw (%s): ", buffer.length, buffer.toString('base64'));
zlib.inflateRaw(buffer, function(err, buffer) {
if (!err) {
console.log("inflateRaw (%s): ", buffer.length, buffer.toString());
}
});
}
});
zlib.gzip(input, function(err, buffer) {
if (!err) {
console.log("gzip (%s): ", buffer.length, buffer.toString('base64'));
zlib.gunzip(buffer, function(err, buffer) {
if (!err) {
console.log("gunzip (%s): ", buffer.length, buffer.toString());
}
});
zlib.unzip(buffer, function(err, buffer) {
if (!err) {
console.log("unzip gzip (%s): ", buffer.length, buffer.toString());
}
});
}
});输出结果：
"C:\Program Files (x86)\JetBrains\WebStorm 11.0.3\bin\runnerw.exe" F:\nodejs\node.exe zlib_buffers.js
deflate (18): eJzT00MBJakVJagiegB9Zgcq
deflateRaw (12): 09NDASWpFSWoInoA
gzip (30): H4sIAAAAAAAAC9PTQwElqRUlqCJ6AIq+x+AiAAAA
inflate (34): ...............text...............
unzip deflate (34): ...............text...............
inflateRaw (34): ...............text...............
gunzip (34): ...............text...............
unzip gzip (34): ...............text...............Process finished with exit code 0
二、压缩文件
可通过pipe()将压缩/解压对象从一个流输送到另一个流。
var zlib = require("zlib");
var gzip = zlib.createGzip();
var fs = require('fs');
var inFile = fs.createReadStream('zlib_file.js');
var outFile = fs.createWriteStream('zlib_file.gz');
inFile.pipe(gzip).pipe(outFile);
setTimeout(function(){
var gunzip = zlib.createUnzip({flush: zlib.Z_FULL_FLUSH});
var inFile = fs.createReadStream('zlib_file.gz');
var outFile = fs.createWriteStream('zlib_file.unzipped');
inFile.pipe(gunzip).pipe(outFile);
}, 3000);上面代码中前面是readable流通过pipe使用压缩zlib.createGzip()然后输出到writeable中。后面的是解压的过程。
到此这篇关于Node.js实现压缩与解压数据的文章就介绍到这了。希望对大家的学习有所帮助，也希望大家多多支持脚本之家。