README

A PHP library to compress large JSON documents with repeated structures and values. Helps to reduce the size of a JSON file, for example, during storage or transmission over the network, while preserving the document structure and key names.

Inspired by compress-json. And thanks to @beenotung.

This library is fully compatible with compress-json for NodeJS.

Features

• Supports all JSON types
• Object key order is preserved
• Repeated values are stored only once
• Numbers are encoded in base62 format (0-9A-Za-z)
• Custom Memory providers for store and cache during compress heavy data (see class AbstractMemory). You can pass your custom memory provider through the Compressor::createWithMemory() method
• Passing custom json_encode or json_decode arguments in toJson or decompressJson methods respectively

Special Values

The following special values are supported (v3.2.0 compatibility):

Example:

use CompressJson\Core\Compressor;

$data = [
    'infinity' => INF,
    'negInfinity' => -INF,
    'nan' => NAN,
];

$compressedJson = Compressor::create()
    ->compress($data)
    ->toJson();

// Decompress
$decompressed = Compressor::create()
    ->decompressJson($compressedJson);

var_dump($decompressed['infinity']);    // float(INF)
var_dump($decompressed['negInfinity']); // float(-INF)
var_dump(is_nan($decompressed['nan'])); // bool(true)

Install

Via Composer

composer require inkrot/php-compress-json

Usage

Compress

use CompressJson\Core\Compressor;

$data = [
    'key1' => 'value1',
    'key2' => 'value3',
    'key3' => [
        'nestedKey1' => 'value1'
    ]
];
$compressedJson = Compressor::create()
    ->compress($data)
    ->toJson();

print_r($compressedJson); // encoded string in JSON format

Output:

[["key1","key2","key3","a|0|1|2","value1","value3","nestedKey1","a|6","o|7|4","o|3|4|5|8"],"9"]

Decompress

use CompressJson\Core\Compressor;

$compressedJson = '[["key1","key2","key3","a|0|1|2","value1","value3","nestedKey1","a|6","o|7|4","o|3|4|5|8"],"9"]';
$data = Compressor::create()
    ->decompressJson($compressedJson);

print_r($data); // array

Output:

Array
(
    [key1] => value1
    [key2] => value3
    [key3] => Array
        (
            [nestedKey1] => value1
        )

)

Example structure for efficient compression

use CompressJson\Core\Compressor;
$data = [
    'count' => 3,
    'names' => ['New York', 'London', 'Paris', 'Beijing', 'Moscow'],
    'cities' => [
        [
            'id' => 1,
            'name' => 'New York',
            'countryName' => 'USA',
            'location' => [
                'latitude' => 40.714606,
                'longitude' => -74.002800,
            ],
            'localityType' => 'BIG_CITY',
        ],
        [
            'id' => 2,
            'name' => 'London',
            'countryName' => 'UK',
            'location' => [
                'latitude' => 51.507351,
                'longitude' => -0.127696,
            ],
            'localityType' => 'COUNTRY_CAPITAL',
        ],
        [
            'id' => 3,
            'name' => 'Paris',
            'countryName' => 'France',
            'location' => [
                'latitude' => 48.856663,
                'longitude' => 2.351556,
            ],
            'localityType' => 'COUNTRY_CAPITAL',
        ],
        [
            'id' => 4,
            'name' => 'Beijing',
            'countryName' => 'China',
            'location' => [
                'latitude' => 39.901850,
                'longitude' => 116.391441,
            ],
            'localityType' => 'COUNTRY_CAPITAL',
        ],
        [
            'id' => 5,
            'name' => 'Moscow',
            'countryName' => 'Russia',
            'location' => [
                'latitude' => 55.755864,
                'longitude' => 37.617698,
            ],
            'localityType' => 'COUNTRY_CAPITAL',
        ],
    ]
];
$compressedJson = Compressor::create()
    ->compress($data)
    ->toJson();
    
print_r(json_encode($data));
echo PHP_EOL;
print_r($compressedJson);

Pure JSON (749 chars)

{"count":3,"names":["New York","London","Paris","Beijing","Moscow"],"cities":[{"id":1,"name":"New York","countryName":"USA","location":{"latitude":40.714606,"longitude"
:-74.0028},"localityType":"BIG_CITY"},{"id":2,"name":"London","countryName":"UK","location":{"latitude":51.507351,"longitude":-0.127696},"localityType":"COUNTRY_CAPITAL
"},{"id":3,"name":"Paris","countryName":"France","location":{"latitude":48.856663,"longitude":2.351556},"localityType":"COUNTRY_CAPITAL"},{"id":4,"name":"Beijing","coun
tryName":"China","location":{"latitude":39.90185,"longitude":116.391441},"localityType":"COUNTRY_CAPITAL"},{"id":5,"name":"Moscow","countryName":"Russia","location":{"l
atitude":55.755864,"longitude":37.617698},"localityType":"COUNTRY_CAPITAL"}]}

Compressed JSON (562 chars)

[["count","names","cities","a|0|1|2","n|3","New York","London","Paris","Beijing","Moscow","a|5|6|7|8|9","id","name","countryName","location","localityType","a|B|C|D|E|F
","n|1","USA","latitude","longitude","a|J|K","n|e.2Xkv","n|-1C.28G","o|L|M|N","BIG_CITY","o|G|H|5|I|O|P","n|2","UK","n|p.dz7","n|-0.2vFR","o|L|T|U","COUNTRY_CAPITAL","o
|G|R|6|S|V|W","France","n|m.1XNq","n|2.2kQz","o|L|Z|a","o|G|4|7|Y|b|W","n|4","China","n|d.F7F","n|1s.bVh","o|L|f|g","o|G|d|8|e|h|W","n|5","Russia","n|t.1xtN","n|b.3lHA"
,"o|L|l|m","o|G|j|9|k|n|W","a|Q|X|c|i|o","o|3|4|A|p"],"q"]

In this example, compression gives an efficiency of 25%. However, the more complex and repetitive the structure, the greater the compression efficiency.

Testing

composer test

Credits

• Islam Zaripov (author)
• compress-json by Beeno Tung (the same library for NodeJS)

License

BSD 2-Clause License (Free Open Sourced Software)