# pako

**Repository Path**: jay924/pako

## Basic Information

- **Project Name**: pako
- **Description**: 前后端数据压缩节省带宽方案(来源Github地址: https://github.com/nodeca/pako.git)
- **Primary Language**: JavaScript
- **License**: MIT
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 1
- **Forks**: 1
- **Created**: 2023-09-11
- **Last Updated**: 2023-09-11

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

pako
==========================================

[![CI](https://github.com/nodeca/pako/workflows/CI/badge.svg)](https://github.com/nodeca/pako/actions)
[![NPM version](https://img.shields.io/npm/v/pako.svg)](https://www.npmjs.org/package/pako)

> zlib port to javascript, very fast!

__Why pako is cool:__

- Results are binary equal to well known [zlib](http://www.zlib.net/) (now contains ported zlib v1.2.8).
- Almost as fast in modern JS engines as C implementation (see benchmarks).
- Works in browsers, you can browserify any separate component.

This project was done to understand how fast JS can be and is it necessary to
develop native C modules for CPU-intensive tasks. Enjoy the result!


__Benchmarks:__


node v12.16.3 (zlib 1.2.9), 1mb input sample:

```
deflate-imaya x 4.75 ops/sec ±4.93% (15 runs sampled)
deflate-pako x 10.38 ops/sec ±0.37% (29 runs sampled)
deflate-zlib x 17.74 ops/sec ±0.77% (46 runs sampled)
gzip-pako x 8.86 ops/sec ±1.41% (29 runs sampled)
inflate-imaya x 107 ops/sec ±0.69% (77 runs sampled)
inflate-pako x 131 ops/sec ±1.74% (82 runs sampled)
inflate-zlib x 258 ops/sec ±0.66% (88 runs sampled)
ungzip-pako x 115 ops/sec ±1.92% (80 runs sampled)
```

node v14.15.0 (google's zlib), 1mb output sample:

```
deflate-imaya x 4.93 ops/sec ±3.09% (16 runs sampled)
deflate-pako x 10.22 ops/sec ±0.33% (29 runs sampled)
deflate-zlib x 18.48 ops/sec ±0.24% (48 runs sampled)
gzip-pako x 10.16 ops/sec ±0.25% (28 runs sampled)
inflate-imaya x 110 ops/sec ±0.41% (77 runs sampled)
inflate-pako x 134 ops/sec ±0.66% (83 runs sampled)
inflate-zlib x 402 ops/sec ±0.74% (87 runs sampled)
ungzip-pako x 113 ops/sec ±0.62% (80 runs sampled)
```

zlib's test is partially affected by marshalling (that make sense for inflate only).
You can change deflate level to 0 in benchmark source, to investigate details.
For deflate level 6 results can be considered as correct.

__Install:__

```
npm install pako
```


Examples / API
--------------

Full docs - http://nodeca.github.io/pako/

```javascript
const pako = require('pako');

// Deflate
//
const input = new Uint8Array();
//... fill input data here
const output = pako.deflate(input);

// Inflate (simple wrapper can throw exception on broken stream)
//
const compressed = new Uint8Array();
//... fill data to uncompress here
try {
  const result = pako.inflate(compressed);
  // ... continue processing
} catch (err) {
  console.log(err);
}

//
// Alternate interface for chunking & without exceptions
//

const deflator = new pako.Deflate();

deflator.push(chunk1, false);
deflator.push(chunk2); // second param is false by default.
...
deflator.push(chunk_last, true); // `true` says this chunk is last

if (deflator.err) {
  console.log(deflator.msg);
}

const output = deflator.result;


const inflator = new pako.Inflate();

inflator.push(chunk1);
inflator.push(chunk2);
...
inflator.push(chunk_last); // no second param because end is auto-detected

if (inflator.err) {
  console.log(inflator.msg);
}

const output = inflator.result;
```

Sometime you can wish to work with strings. For example, to send
stringified objects to server. Pako's deflate detects input data type, and
automatically recode strings to utf-8 prior to compress. Inflate has special
option, to say compressed data has utf-8 encoding and should be recoded to
javascript's utf-16.

```javascript
const pako = require('pako');

const test = { my: 'super', puper: [456, 567], awesome: 'pako' };

const compressed = pako.deflate(JSON.stringify(test));

const restored = JSON.parse(pako.inflate(compressed, { to: 'string' }));
```


Notes
-----

Pako does not contain some specific zlib functions:

- __deflate__ -  methods `deflateCopy`, `deflateBound`, `deflateParams`,
  `deflatePending`, `deflatePrime`, `deflateTune`.
- __inflate__ - methods `inflateCopy`, `inflateMark`,
  `inflatePrime`, `inflateGetDictionary`, `inflateSync`, `inflateSyncPoint`, `inflateUndermine`.
- High level inflate/deflate wrappers (classes) may not support some flush
  modes.


pako for enterprise
-------------------

Available as part of the Tidelift Subscription

The maintainers of pako and thousands of other packages are working with Tidelift to deliver commercial support and maintenance for the open source dependencies you use to build your applications. Save time, reduce risk, and improve code health, while paying the maintainers of the exact dependencies you use. [Learn more.](https://tidelift.com/subscription/pkg/npm-pako?utm_source=npm-pako&utm_medium=referral&utm_campaign=enterprise&utm_term=repo)


Authors
-------

- Andrey Tupitsin [@anrd83](https://github.com/andr83)
- Vitaly Puzrin [@puzrin](https://github.com/puzrin)

Personal thanks to:

- Vyacheslav Egorov ([@mraleph](https://github.com/mraleph)) for his awesome
  tutorials about optimising JS code for v8, [IRHydra](http://mrale.ph/irhydra/)
  tool and his advices.
- David Duponchel ([@dduponchel](https://github.com/dduponchel)) for help with
  testing.

Original implementation (in C):

- [zlib](http://zlib.net/) by Jean-loup Gailly and Mark Adler.


License
-------

- MIT - all files, except `/lib/zlib` folder
- ZLIB - `/lib/zlib` content


# PHP+JS(pako)前后端数据压缩,节省带宽方案

## 一、准备工具
1.pako脚本库
- gitee地址：https://gitee.com/renew_old_romance/pako
- github地址： https://github.com/nodeca/pako

2.前端Uint8Array与Base64互转函数（代码如下）
```javascript
// uint8array转为base64字符串
function uint8arrayToBase64(u8Arr) {
    let CHUNK_SIZE = 0x8000; //arbitrary number
    let index = 0;
    let length = u8Arr.length;
    let result = '';
    let slice;
    while (index < length) {
        slice = u8Arr.subarray(index, Math.min(index + CHUNK_SIZE, length));
        result += String.fromCharCode.apply(null, slice);
        index += CHUNK_SIZE;
    }
    // web image base64图片格式: "data:image/png;base64," + b64encoded;
    // return  "data:image/png;base64," + btoa(result);
    return btoa(result);
}
// base64字符串转为uint8array数组
function base64ToUint8Array(base64String) {
    let padding = '='.repeat((4 - base64String.length % 4) % 4);
    let base64 = (base64String + padding)
        .replace(/\-/g, '+')
        .replace(/_/g, '/');
    let rawData = window.atob(base64);
    let outputArray = new Uint8Array(rawData.length);
    for (var i = 0; i < rawData.length; ++i) {
        outputArray[i] = rawData.charCodeAt(i);
    }
    return outputArray;
}
```
## 二、具体用法案例
1.前端JS压缩+后端PHP解压
JS压缩
```javascript
// JS压缩，注意：需要引入dist/pako_deflate.js(仅支持压缩)或dist/pako.js(支持压缩和解压)
var rawData = {title:"this is pako.defalte test",author: "slongzhang@qq.com", date: "2021-04-02", content: "test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test"}
var binaryString = pako.deflateRaw(JSON.stringify(rawData), { to: 'string' });
var compressedBase64  = uint8arrayToBase64(binaryString);
console.log(compressedBase64);// q1YqySzJSVWyUirJyCxWAKKCxOx8vZTUtMScklSFktTiEiUdpcTSkoz8IqCi4pz8vPSqjMS8dIfCQr3k/FygZEpiCUi/kYGRoa6Bia6BEVAsOT+vJDWvBGQs0ASFUWKUwEco1QIA
```
![](https://ftp.bmp.ovh/imgs/2021/06/fe0d5642f01b3afb.jpg)

PHP解压
```php
// PHP解压
$base64String = 'q1YqySzJSVWyUirJyCxWAKKCxOx8vZTUtMScklSFktTiEiUdpcTSkoz8IqCi4pz8vPSqjMS8dIfCQr3k/FygZEpiCUi/kYGRoa6Bia6BEVAsOT+vJDWvBGQs0ASFUWKUwEco1QIA';
print_r(gzinflate(base64_decode($base64String)));
```
![](https://ftp.bmp.ovh/imgs/2021/06/fb32285b321cb243.jpg)

2.后端PHP压缩+前端JS解压
PHP压缩
```php
// php压缩
$array = array(
  "title"       => "this is pako.defalte test",
  "author"      => "slongzhang@qq.com",
  "date"        => "2021-04-02",
  "content"       => "test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test test"
);
function compress($str) { return base64_encode(gzdeflate($str, 9)); }
echo compress(json_encode($array,256));
// q1YqySzJSVWyUirJyCxWAKKCxOx8vZTUtMScklSFktTiEiUdpcTSkoz8IqCi4pz8vPSqjMS8dIfCQr3k/FygZEpiCUi/kYGRoa6Bia6BEVAsOT+vJDWvBGQs0ASFUWKUwEco1QIA
```
![](https://ftp.bmp.ovh/imgs/2021/06/a5930ef7091ca4a2.jpg)

JS解压
```javascript
// JS解压，注意：需要引入dist/pako_inflate.js(仅支持压缩)或dist/pako.js(支持压缩和解压)
var decompress = function(str){
    return pako.inflateRaw(base64ToUint8Array(str), {to: 'string'});
}
var rawData = decompress('q1YqySzJSVWyUirJyCxWAKKCxOx8vZTUtMScklSFktTiEiUdpcTSkoz8IqCi4pz8vPSqjMS8dIfCQr3k/FygZEpiCUi/kYGRoa6Bia6BEVAsOT+vJDWvBGQs0ASFUWKUwEco1QIA');
console.log(rawData);
```
![](https://ftp.bmp.ovh/imgs/2021/06/60679770b1dc6b0b.jpg)

## 三、注意事项
1.前端JS
- 必须引入Uint8Array与Base64互转函数
- 如果不需要同时处理压缩和解压可按需单独引入脚本pako_deflate.min.js（压缩）| pako_inflate.min.js（解压）；
- 如果需要同时处理压缩和解压那么请直接引入pako.min.js
![](https://ftp.bmp.ovh/imgs/2021/06/ddf209c8744a0bfc.jpg)

2.PHP要求(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)
- 简单分享快乐学习，如有错误请多包涵！