README

This is a JSONPath implementation for PHP based on Stefan Goessner's JSONPath script.

JSONPath is an XPath-like expression language for filtering, flattening and extracting data.

This project aims to be a clean and simple implementation with the following goals:

Object-oriented code (should be easier to manage or extend in future)
Expressions are parsed into tokens using code inspired by the Doctrine Lexer. The tokens are cached internally to avoid re-parsing the expressions.
There is no eval() in use
Any combination of objects/arrays/ArrayAccess-objects can be used as the data input which is great if you're de-serializing JSON in to objects or if you want to process your own data structures.

Installation

composer require softcreatr/jsonpath:"^0.9"

JSONPath Examples

JSONPath	Result
`$.store.books[*].author`	the authors of all books in the store
`$..author`	all authors
`$.store..price`	the price of everything in the store.
`$..books[2]`	the third book
`$..books[(@.length-1)]`	the last book in order.
`$..books[-1:]`	the last book in order.
`$..books[0,1]`	the first two books
`$..books[:2]`	the first two books
`$..books[::2]`	every second book starting from first one
`$..books[1:6:3]`	every third book starting from 1 till 6
`$..books[?(@.isbn)]`	filter all books with isbn number
`$..books[?(@.price<10)]`	filter all books cheaper than 10
`$..books.length`	the amount of books
`$..*`	all elements in the data (recursively extracted)

Expression syntax

Symbol	Description
`$`	The root object/element (not strictly necessary)
`@`	The current object/element
`.` or `[]`	Child operator
`..`	Recursive descent
`*`	Wildcard. All child elements regardless their index.
`[,]`	Array indices as a set
`[start:end:step]`	Array slice operator borrowed from ES4/Python.
`?()`	Filters a result set by a script expression
`()`	Uses the result of a script expression as the index

PHP Usage

Using arrays

<?php
require_once __DIR__ . '/vendor/autoload.php';

$data = ['people' => [
    ['name' => 'Sascha'],
    ['name' => 'Bianca'],
    ['name' => 'Alexander'],
    ['name' => 'Maximilian'],
]];

print_r((new \Flow\JSONPath\JSONPath($data))->find('$.people.*.name')->getData());

/*
Array
(
    [0] => Sascha
    [1] => Bianca
    [2] => Alexander
    [3] => Maximilian
)
*/

Using objects

<?php
require_once __DIR__ . '/vendor/autoload.php';

$data = json_decode('{"name":"Sascha Greuel","birthdate":"1987-12-16","city":"Gladbeck","country":"Germany"}', false);

print_r((new \Flow\JSONPath\JSONPath($data))->find('$')->getData()[0]);

/*
stdClass Object
(
    [name] => Sascha Greuel
    [birthdate] => 1987-12-16
    [city] => Gladbeck
    [country] => Germany
)
*/

More examples can be found in the Wiki

Magic method access

The options flag JSONPath::ALLOW_MAGIC will instruct JSONPath when retrieving a value to first check if an object has a magic __get() method and will call this method if available. This feature is iffy and not very predictable as:

wildcard and recursive features will only look at public properties and can't smell which properties are magically accessible
there is no property_exists check for magic methods so an object with a magic __get() will always return true when checking if the property exists
any errors thrown or unpredictable behaviour caused by fetching via __get() is your own problem to deal with

use Flow\JSONPath\JSONPath;

$myObject = (new Foo())->get('bar');
$jsonPath = new JSONPath($myObject, JSONPath::ALLOW_MAGIC);

For more examples, check the JSONPathTest.php tests file.

Script expressions

Script expressions are not supported as the original author intended because:

This would only be achievable through eval (boo).
Using the script engine from different languages defeats the purpose of having a single expression evaluate the same way in different languages which seems like a bit of a flaw if you're creating an abstract expression syntax.

So here are the types of query expressions that are supported:

[?(@._KEY_ _OPERATOR_ _VALUE_)] // <, >, <=, >=, !=, ==, =~, in and nin
e.g.
[?(@.title == "A string")] //
[?(@.title = "A string")]
// A single equals is not an assignment but the SQL-style of '=='
[?(@.title =~ /^a(nother)? string$/i)]
[?(@.title in ["A string", "Another string"])]
[?(@.title nin ["A string", "Another string"])]

Known issues

This project has not implemented multiple string indexes e.g. $[name,year] or $["name","year"]. I have no ETA on that feature, and it would require some re-writing of the parser that uses a very basic regex implementation.

Similar projects

FlowCommunications/JSONPath is the predecessor of this library by Stephen Frank

Other / Similar implementations can be found in the Wiki.

Changelog

A list of changes can be found in the CHANGELOG.md file.

License 🌳

MIT © 1-2.dev

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