JSON Schema for PHP

A PHP Implementation for validating JSON Structures against a given Schema with support for Schemas of Draft-3, Draft-4 or Draft-6.

Features of newer Drafts might not be supported. See Table of All Versions of Everything to get an overview of all existing Drafts. See json-schema for more details about the JSON Schema specification

Compliance

Installation

Library

git clone https://github.com/jsonrainbow/json-schema.git

Composer

Install PHP Composer

composer require justinrainbow/json-schema

Usage

For a complete reference see Understanding JSON Schema.

Note: features of Drafts newer than Draft-4 might not be supported!

Basic usage

<?php

$data = json_decode(file_get_contents('data.json'));

// Validate
$validator = new JsonSchema\Validator;
$validator->validate($data, (object)['$ref' => 'file://' . realpath('schema.json')]);

if ($validator->isValid()) {
    echo "The supplied JSON validates against the schema.\n";
} else {
    echo "JSON does not validate. Violations:\n";
    foreach ($validator->getErrors() as $error) {
        printf("[%s] %s\n", $error['property'], $error['message']);
    }
}

Type coercion

If you're validating data passed to your application via HTTP, you can cast strings and booleans to the expected types defined by your schema:

<?php

use JsonSchema\SchemaStorage;
use JsonSchema\Validator;
use JsonSchema\Constraints\Factory;
use JsonSchema\Constraints\Constraint;

$request = (object)[
    'processRefund'=>"true",
    'refundAmount'=>"17"
];

$validator->validate(
    $request, (object) [
        "type"=>"object",
        "properties"=>(object)[
            "processRefund"=>(object)[
                "type"=>"boolean"
            ],
            "refundAmount"=>(object)[
                "type"=>"number"
            ]
        ]
    ],
    Constraint::CHECK_MODE_COERCE_TYPES
); // validates!

is_bool($request->processRefund); // true
is_int($request->refundAmount); // true

A shorthand method is also available:

$validator->coerce($request, $schema);
// equivalent to $validator->validate($data, $schema, Constraint::CHECK_MODE_COERCE_TYPES);

Default values

If your schema contains default values, you can have these automatically applied during validation:

<?php

use JsonSchema\Validator;
use JsonSchema\Constraints\Constraint;

$request = (object)[
    'refundAmount'=>17
];

$validator = new Validator();

$validator->validate(
    $request,
    (object)[
        "type"=>"object",
        "properties"=>(object)[
            "processRefund"=>(object)[
                "type"=>"boolean",
                "default"=>true
            ]
        ]
    ],
    Constraint::CHECK_MODE_APPLY_DEFAULTS
); //validates, and sets defaults for missing properties

is_bool($request->processRefund); // true
$request->processRefund; // true

With inline references

<?php

use JsonSchema\SchemaStorage;
use JsonSchema\Validator;
use JsonSchema\Constraints\Factory;

$jsonSchema = <<<'JSON'
{
    "type": "object",
    "properties": {
        "data": {
            "oneOf": [
                { "$ref": "#/definitions/integerData" },
                { "$ref": "#/definitions/stringData" }
            ]
        }
    },
    "required": ["data"],
    "definitions": {
        "integerData" : {
            "type": "integer",
            "minimum" : 0
        },
        "stringData" : {
            "type": "string"
        }
    }
}
JSON;

// Schema must be decoded before it can be used for validation
$jsonSchemaObject = json_decode($jsonSchema);

// The SchemaStorage can resolve references, loading additional schemas from file as needed, etc.
$schemaStorage = new SchemaStorage();

// This does two things:
// 1) Mutates $jsonSchemaObject to normalize the references (to file://mySchema#/definitions/integerData, etc)
// 2) Tells $schemaStorage that references to file://mySchema... should be resolved by looking in $jsonSchemaObject
$schemaStorage->addSchema('file://mySchema', $jsonSchemaObject);

// Provide $schemaStorage to the Validator so that references can be resolved during validation
$jsonValidator = new Validator(new Factory($schemaStorage));

// JSON must be decoded before it can be validated
$jsonToValidateObject = json_decode('{"data":123}');

// Do validation (use isValid() and getErrors() to check the result)
$jsonValidator->validate($jsonToValidateObject, $jsonSchemaObject);

Configuration Options

A number of flags are available to alter the behavior of the validator. These can be passed as the third argument to Validator::validate(), or can be provided as the third argument to Factory::__construct() if you wish to persist them across multiple validate() calls.

Flag	Description
Constraint::CHECK_MODE_NORMAL	Validate in 'normal' mode - this is the default
Constraint::CHECK_MODE_TYPE_CAST	Enable fuzzy type checking for associative arrays and objects
Constraint::CHECK_MODE_COERCE_TYPES 12	Convert data types to match the schema where possible
Constraint::CHECK_MODE_EARLY_COERCE 2	Apply type coercion as soon as possible
Constraint::CHECK_MODE_APPLY_DEFAULTS 1	Apply default values from the schema if not set
Constraint::CHECK_MODE_ONLY_REQUIRED_DEFAULTS	When applying defaults, only set values that are required
Constraint::CHECK_MODE_EXCEPTIONS	Throw an exception immediately if validation fails
Constraint::CHECK_MODE_DISABLE_FORMAT	Do not validate "format" constraints
Constraint::CHECK_MODE_VALIDATE_SCHEMA	Validate the schema as well as the provided document
Constraint::CHECK_MODE_STRICT 3	Validate the scheme using strict mode using the specified draft

Running the tests

composer test                            # run all unit tests
composer testOnly TestClass              # run specific unit test class
composer testOnly TestClass::testMethod  # run specific unit test method
composer style-check                     # check code style for errors
composer style-fix                       # automatically fix code style errors

Contributors ✨

Thanks go to these wonderful people, without their effort this project wasn't possible.

Footnotes

1. Please note that using CHECK_MODE_COERCE_TYPES or CHECK_MODE_APPLY_DEFAULTS will modify your original data. ↩ ↩²

2. CHECK_MODE_EARLY_COERCE has no effect unless used in combination with CHECK_MODE_COERCE_TYPES. If enabled, the validator will use (and coerce) the first compatible type it encounters, even if the schema defines another type that matches directly and does not require coercion. ↩ ↩²

3. CHECK_MODE_STRICT only can be used for Draft-6 at this point. ↩