webmozart / json

src/Validation/ValidatingConverter.php

<?php

/*
 * This file is part of the webmozart/json package.
 *
 * (c) Bernhard Schussek <bschussek@gmail.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Webmozart\Json\Validation;

use Webmozart\Json\Conversion\ConversionFailedException;
use Webmozart\Json\Conversion\JsonConverter;
use Webmozart\Json\InvalidSchemaException;
use Webmozart\Json\JsonValidator;

/**
 * A decorator for a {@link JsonCoverter} that validates the JSON data.
 *
 * Pass the path to the schema to the constructor:
 *
 * ~~~php
 * $converter = ConfigFileConverter();
 *
 * // Decorate the converter
 * $converter = new ValidatingConverter($converter, __DIR__.'/schema.json');
 * ~~~
 *
 * Whenever you load or dump data as JSON, the JSON structure is validated
 * against the schema:
 *
 * ~~~php
 * $jsonDecoder = new JsonDecoder();
 * $configFile = $converter->fromJson($jsonDecoder->decode($json));
 *
 * $jsonEncoder = new JsonEncoder();
 * $jsonEncoder->encode($converter->toJson($configFile));
 * ~~~
 *
 * If you want to dynamically determine the path to the schema file, pass a
 * callable instead of the string. This is especially useful when versioning
 * your JSON data:
 *
 * ~~~php
 * $converter = ConfigFileConverter();
 *
 * // Calculate the schema path based on the "version" key in the JSON object
 * $getSchemaPath = function ($jsonData) {
 *     return __DIR__.'/schema-'.$jsonData->version.'.json';
 * }
 *
 * // Decorate the converter
 * $converter = new ValidatingConverter($converter, $getSchemaPath);
 * ~~~
 *
 * @since  1.3
 *
 * @author Bernhard Schussek <bschussek@gmail.com>
 */
class ValidatingConverter implements JsonConverter
{
    /**
     * @var JsonConverter
     */
    private $innerConverter;

    /**
     * @var mixed
     */
    private $schema;

    /**
     * @var JsonValidator
     */
    private $jsonValidator;

    /**
     * Creates the converter.
     *
     * @param JsonConverter        $innerConverter The decorated converter
     * @param string|callable|null $schema         The path to the schema file
     *                                             or a callable for calculating
     *                                             the path dynamically for a
     *                                             given JSON data. If `null`,
     *                                             the schema is taken from the
     *                                             `$schema` property of the
     *                                             JSON data
     * @param JsonValidator        $jsonValidator  The JSON validator (optional)

Should the type for parameter $jsonValidator not be null|JsonValidator?

     */
    public function __construct(JsonConverter $innerConverter, $schema = null, JsonValidator $jsonValidator = null)
    {
        $this->innerConverter = $innerConverter;
        $this->schema = $schema;
        $this->jsonValidator = $jsonValidator ?: new JsonValidator();
    }

    /**
     * {@inheritdoc}
     */
    public function toJson($data, array $options = array())
    {
        $jsonData = $this->innerConverter->toJson($data, $options);

        $this->validate($jsonData);

        return $jsonData;
    }

    /**
     * {@inheritdoc}
     */
    public function fromJson($jsonData, array $options = array())
    {
        $this->validate($jsonData);

        return $this->innerConverter->fromJson($jsonData, $options);
    }

    private function validate($jsonData)
    {
        $schema = $this->schema;

        if (is_callable($schema)) {
            $schema = $schema($jsonData);
        }

        try {
            $errors = $this->jsonValidator->validate($jsonData, $schema);
        } catch (InvalidSchemaException $e) {
            throw new ConversionFailedException(sprintf(
                'An error occurred while loading the JSON schema (%s): %s',
                is_string($schema) ? '"'.$schema.'"' : gettype($schema),
                $e->getMessage()
            ), 0, $e);
        }

        if (count($errors) > 0) {
            throw new ConversionFailedException(sprintf(
                "The passed JSON did not match the schema:\n%s",
                implode("\n", $errors)
            ));
        }
    }
}