rfc:is_json

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revision		Previous revision
Last revisionBoth sides next revision
rfc:is_json [2022/08/15 19:12] – juan_moralesrfc:is_json [2022/08/17 14:00] – juan_morales
Line 5: Line 5:
   * Status: Draft   * Status: Draft
   * First Published at: http://wiki.php.net/rfc/is_json   * First Published at: http://wiki.php.net/rfc/is_json
 +  * Implementation: https://github.com/php/php-src/pull/9355
  
 ===== Preliminary note ===== ===== Preliminary note =====
Line 14: Line 15:
  
 Most userland implementations to achieve this are done using json_decode() which by design generates an object/array while parsing the string, ergo using memory and processing, that could be save. Most userland implementations to achieve this are done using json_decode() which by design generates an object/array while parsing the string, ergo using memory and processing, that could be save.
- 
-===== Fundaments/Reasons ===== 
-==== Disadvantages of using json_decode ==== 
- 
-By design, json_decode() generates an object/array while parsing the string, ergo using memory and processing for it, that is not needed if the only thing to discover is if a string contains a valid json. 
- 
-==== Disadvantages of using regex ==== 
- 
-Using a regex for this task forces different, error-prone, hard to maintain, implementations. 
- 
-==== Needs from major projects and developers ==== 
- 
-In the "References" section, there is a list of major open-source php projects needing this feature; also in th mntioned section can find a link to one of the most popular StackOverflow questions, which somehow reflects the need from our developers to have a feature like this included. 
- 
-==== Why not using a 3rd party package for this ==== 
- 
-- This feature is very web related, which is a huge coincidence with the first lines of the default RFC template provided to "us": 
-<blockquote> 
-PHP is and should remain: 
-> 1) a pragmatic web-focused language .... 
-</blockquote> 
- 
-- We should not force the community to install 3rd party packages for this kind of features (feature totally aligned with PHP's principles, and very easy to achieve), which would generate a dependency between the project and the package. 
- 
-==== Complexity added in the core ==== 
- 
-At the moment, there is a JSON parser in the core, used by json_decode to do its job, so there is no need to write a new JSON parser for this RFC; the proposed function will use the existing JSON parser exclusively to parse an string without generating any object/array in memory for it. 
- 
-==== Name of the function ==== 
- 
-If the links provided in the "References" section are checked, one can see that some of those major projects have created a function called this isJson(). 
  
 ===== Proposal ===== ===== Proposal =====
Line 76: Line 46:
  
 Returns **true** if the string passed contains a valid json, otherwise returns **false**. Returns **true** if the string passed contains a valid json, otherwise returns **false**.
 +
 +==== Extra behavior ====
 +-
 +==== Examples ====
 +-
 +===== Fundaments/Reasons =====
 +==== Disadvantages of using json_decode ====
 +
 +By design, json_decode() generates an object/array while parsing the string, ergo using memory and processing for it, that is not needed if the only thing to discover is if a string contains a valid json.
 +
 +==== Disadvantages of using regex ====
 +
 +Using a regex for this task forces different, error-prone, hard to maintain, implementations.
 +
 +==== Needs from major projects and developers ====
 +
 +In the "References" section, there is a list of major open-source php projects needing this feature; also in th mntioned section can find a link to one of the most popular StackOverflow questions, which somehow reflects the need from our developers to have a feature like this included.
 +
 +==== Complexity added in the core ====
 +
 +At the moment, there is a JSON parser in the core, used by json_decode to do its job, so there is no need to write a new JSON parser for this RFC; the proposed function will use the existing JSON parser exclusively to parse an string without generating any object/array in memory for it.
  
 ===== Backward Incompatible Changes ===== ===== Backward Incompatible Changes =====
Line 101: Line 92:
  
 ===== References ===== ===== References =====
-- (To be done later) + 
--- Links to external references, discussions or RFCs +__Major Open-Source projects needing this__ 
--- Links to major open-source projects emulating this function using json_decode + 
--- Link to Stackoverflow pointing the question, which this proposed function satisfy the needs+[[https://github.com/symfony/symfony/blob/870eeb975feb1abb4b8a1722e1fd57beeab2b230/src/Symfony/Component/Validator/Constraints/JsonValidator.php|Symfony Framework]] 
 + 
 +<code php> 
 +class JsonValidator extends ConstraintValidator 
 +</code> 
 + 
 +[[https://github.com/laravel/framework/blob/302a579f00ebcb2573f481054cbeadad9c970605/src/Illuminate/Validation/Concerns/ValidatesAttributes.php|Laravel Framework]] 
 + 
 +<code php> 
 +    public function validateJson($attribute, $value) 
 +    { 
 +        if (is_array($value)) { 
 +            return false; 
 +        } 
 + 
 +        if (! is_scalar($value) && ! is_null($value) && ! method_exists($value, '__toString')) { 
 +            return false; 
 +        } 
 + 
 +        json_decode($value); 
 + 
 +        return json_last_error() === JSON_ERROR_NONE; 
 +    } 
 +</code> 
 + 
 +[[https://github.com/laravel/framework/blob/61eac9cae4717699ecb3941b16c3d775820d4ca2/src/Illuminate/Support/Str.php|Laravel Framework]] 
 + 
 +<code php> 
 +    public static function isJson($value) 
 +    { 
 +</code> 
 + 
 +[[https://github.com/magento/magento2/blob/7c6b6365a3c099509d6f6e6c306cb1821910aab0/app/code/Magento/User/Block/Role/Grid/User.php|Magento]] 
 + 
 +<code php> 
 +    private function getJSONString($input) 
 +    { 
 +        $output = json_decode($input); 
 +        return $output ? $this->_jsonEncoder->encode($output) : '{}'; 
 +    } 
 +</code> 
 + 
 +[[https://github.com/magento/magento2/blob/7c6b6365a3c099509d6f6e6c306cb1821910aab0/lib/internal/Magento/Framework/DB/DataConverter/SerializedToJson.php|Magento]] 
 + 
 +<code php> 
 +    protected function isValidJsonValue($value) 
 +    { 
 +        if (in_array($value, ['null', 'false', '0', '""', '[]']) 
 +            || (json_decode($value) !== null && json_last_error() === JSON_ERROR_NONE) 
 +        ) { 
 +            return true; 
 +        } 
 +        //JSON last error reset 
 +        json_encode([]); 
 +        return false; 
 +    } 
 +</code> 
 + 
 +[[https://github.com/magento/magento2/blob/7c6b6365a3c099509d6f6e6c306cb1821910aab0/lib/internal/Magento/Framework/Serialize/JsonValidator.php|Magento]] 
 + 
 +<code php> 
 +    public function isValid($string) 
 +    { 
 +        if ($string !== false && $string !== null && $string !== '') { 
 +            json_decode($string); 
 +            if (json_last_error() === JSON_ERROR_NONE) { 
 +                return true; 
 +            } 
 +        } 
 +        return false; 
 +    } 
 +</code> 
 + 
 + 
 +[[https://github.com/getgrav/grav/blob/3e7f67f589267e61f823d19824f3ee1b9a8a38ff/system/src/Grav/Common/Data/Validation.php|getgrav]] 
 + 
 +<code php> 
 +    public static function validateJson($value, $params) 
 +    { 
 +        return (bool) (@json_decode($value)); 
 +    } 
 +</code> 
 + 
 + 
 +[[https://github.com/symfony/http-kernel/blob/94986633e4c3e7facb7defbd094a2e1170486ab5/DataCollector/RequestDataCollector.php|Symfony htp-kernel ]] 
 + 
 +<code php> 
 +    public function getPrettyJson() 
 +    { 
 +        $decoded = json_decode($this->getContent()); //<------ here  
 + 
 +        return \JSON_ERROR_NONE === json_last_error() ? json_encode($decoded, \JSON_PRETTY_PRINT) : null; 
 +    } 
 +</code> 
 + 
 + 
 +[[https://github.com/Respect/Validation/blob/3dcd859d986f1b586b5539ea19962723ab7352ed/library/Rules/Json.php|Respect / Validation]] 
 + 
 +<code php> 
 +final class Json extends AbstractRule 
 +{ 
 +    /** 
 +     * {@inheritDoc} 
 +     */ 
 +    public function validate($input): bool 
 +    { 
 +        if (!is_string($input) || $input === '') { 
 +            return false; 
 +        } 
 + 
 +        json_decode($input); 
 + 
 +        return json_last_error() === JSON_ERROR_NONE; 
 +    } 
 +} 
 +</code> 
 + 
 +[[https://github.com/Respect/Validation/blob/3dcd859d986f1b586b5539ea19962723ab7352ed/library/Rules/Json.php|Respect / Validation]] 
 + 
 +<code php> 
 +final class Json extends AbstractRule 
 +{ 
 +    /** 
 +     * {@inheritDoc} 
 +     */ 
 +    public function validate($input): bool 
 +    { 
 +        if (!is_string($input) || $input === '') { 
 +            return false; 
 +        } 
 + 
 +        json_decode($input); 
 + 
 +        return json_last_error() === JSON_ERROR_NONE; 
 +    } 
 +} 
 +</code> 
 + 
 +[[https://github.com/humhub/humhub/blob/26d7e2667a9317057abe335a056ac8e8f4d675fb/protected/humhub/modules/web/security/controllers/ReportController.php|humhub]] 
 + 
 + 
 +<code php> 
 +    public function actionIndex() 
 +    { 
 +        Yii::$app->response->statusCode = 204; 
 + 
 +        if(!SecuritySettings::isReportingEnabled()) { 
 +            return; 
 +        } 
 + 
 +        $json_data = file_get_contents('php://input'); 
 +        if ($json_data = json_decode($json_data)) { //<----- json_decode() just to check if is valid json-string only 
 +            $json_data = json_encode($json_data, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES); 
 +            $json_data = preg_replace('/\'nonce-[^\']*\'/', "'nonce-xxxxxxxxxxxxxxxxxxxxxxxx'", $json_data); 
 +            Yii::error($json_data, 'web.security'); 
 +        } 
 +    } 
 +</code> 
 + 
 +[[https://github.com/PrestaShop/PrestaShop/blob/24f9e510ecb0cb002ac3f4834f3210e8d9359899/classes/Validate.php|Prestashop]] 
 + 
 +<code php> 
 +    public static function isJson($string) 
 +    { 
 +        json_decode($string); 
 + 
 +        return json_last_error() == JSON_ERROR_NONE; 
 +    } 
 +</code> 
 + 
 +[[https://github.com/wp-cli/wp-cli/blob/f3e4b0785aa3d3132ee73be30aedca8838a8fa06/php/utils.php|Wordpress CLI]] 
 + 
 +<code php> 
 +function is_json( $argument, $ignore_scalars = true ) { 
 +    if ( ! is_string( $argument ) || '' === $argument ) { 
 +        return false; 
 +    } 
 + 
 +    if ( $ignore_scalars && ! in_array( $argument[0], [ '{', '[' ], true ) ) { 
 +        return false; 
 +    } 
 + 
 +    json_decode( $argument, $assoc = true ); 
 + 
 +    return json_last_error() === JSON_ERROR_NONE; 
 +} 
 +</code> 
 + 
 +[[https://github.com/joomla/joomla-cms/blob/09d14c65f25f9bc76f2698e69c4d7b35f43bc848/libraries/src/Form/Field/AccessiblemediaField.php|JOOMLA CMS]] 
 + 
 +<code php> 
 +if (\is_string($value)) { 
 +    json_decode($value); //<------ HERE 
 + 
 +    // Check if value is a valid JSON string. 
 +    if ($value !== '' && json_last_error() !== JSON_ERROR_NONE) { 
 +        /** 
 +         * If the value is not empty and is not a valid JSON string, 
 +         * it is most likely a custom field created in Joomla 3 and 
 +         * the value is a string that contains the file name. 
 +        */ 
 +        if (is_file(JPATH_ROOT . '/' . $value)) { 
 +            $value = '{"imagefile":"' . $value . '","alt_text":""}'; 
 +        } else { 
 +            $value = ''; 
 +        } 
 +    } 
 + 
 +</code> 
 + 
 + 
 + 
 +__Stackoverflow questions related to this__ 
 + 
 +In PHP, this question is one of the most high ranked questions related to json && php in stackoverflow, "Fastest way to check if a string is JSON in PHP?" 
 + 
 +[[https://stackoverflow.com/questions/6041741/fastest-way-to-check-if-a-string-is-json-in-php|The question]] 
 + 
 +Viewed 484k times 
 + 
 +[[https://stackoverflow.com/questions/tagged/php%20json?sort=MostVotes&edited=true|The ranking]] 
 + 
 +__Person asking how to do exactly this, also providing a real use case; eventhough in python, the programming language is not important.__ 
 + 
 +[[https://stackoverflow.com/questions/5508509/how-do-i-check-if-a-string-is-valid-json-in-python|In Python]] 
 + 
 +__Someone has also doing exactly this , in JAVA__ 
 + 
 +[[https://stackoverflow.com/questions/3679479/check-if-file-is-json-java|In Java]]
  
 ===== Rejected Features ===== ===== Rejected Features =====
 - No rejected features currently. - No rejected features currently.
rfc/is_json.txt · Last modified: 2022/08/17 14:04 by juan_morales

Page Tools