JSON Schema for PHP

A PHP Implementation for validating JSON Structures against a given Schema.

See json-schema for more details.

Installation

Library

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

Composer

Install PHP Composer

composer require justinrainbow/json-schema

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) {
        echo sprintf("[%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, Convert data types to match the schema where possible, Constraint::CHECK_MODE_EARLY_COERCE, Apply type coercion as soon as possible, Constraint::CHECK_MODE_APPLY_DEFAULTS, 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, Please note that using CHECK_MODE_COERCE_TYPES or CHECK_MODE_APPLY_DEFAULTS will modify your
original data.

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.

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