json_validate

    (PHP 8 >= 8.3.0)

    json_validate — Checks if a string contains valid JSON

    Descripción

    json_validate(string $json, int $depth = 512, int $flags = 0): bool

    Returns whether the given string is syntactically valid JSON. If json_validate() returns true, json_decode() will successfully decode the given string when using the same depth and flags.

    If json_validate() returns false, the cause can be retrieved using json_last_error() and json_last_error_msg().

    json_validate() uses less memory than json_decode() if the decoded JSON payload is not used, because it does not need to build the array or object structure containing the payload.

    Precaución

    Calling json_validate() immediately before json_decode() will unnecessarily parse the string twice, as json_decode() implicitly performs validation during decoding.

    json_validate() should therefore only be used if the decode JSON payload is not immediately used and knowing whether the string contains valid JSON is needed.

    Parámetros

    json

    The string to validate.

    This function only works with UTF-8 encoded strings.

    Nota:

    PHP implementa un superconjunto de JSON tal como se especifica en la » RFC 7159 original.

    depth

    Maximum nesting depth of the structure being decoded. The value must be greater than 0, and less than or equal to 2147483647.

    flags

    Currently only JSON_INVALID_UTF8_IGNORE is accepted.

    Valores devueltos

    Returns true if the given string is syntactically valid JSON, otherwise returns false.

    Errores/Excepciones

    If depth is outside the allowed range, a ValueError is thrown.

    If flags is not a valid flag, a ValueError is thrown.

    Ejemplos

    Ejemplo #1 json_validate() examples

    <?php
    var_dump    (json_validate('{ "test": { "foo": "bar" } }'));
    var_dump(json_validate('{ "": "": "" } }'));
    ?>

    El resultado del ejemplo sería:

    bool(true)
bool(false)

    Ver también

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    User Contributed Notes 2 notes

    up
    20
    Behrad
    11 months ago
    ---------------- PHP < 8.3 ----------------

    function json_validate(string $string): bool {
    json_decode($string);

    return json_last_error() === JSON_ERROR_NONE;
    }

    var_dump(json_validate('{ "test": { "foo": "bar" } }')); // true

    ---------------- PHP >= 8.3 ----------------

    var_dump(json_validate('{ "test": { "foo": "bar" } }')); // true

    Note: code from https://www.php.net/releases/8.3/en.php
    up
    10
    Julien T.
    10 months ago
    Building upon Allan R.'s initial idea, I've developed an improved version of the json_validate function for those using PHP 8.2 and earlier versions. This function emulates the functionality introduced in PHP 8.3, providing an effective way to validate JSON strings in earlier PHP versions.

    ```php
    if (!function_exists('json_validate')) {
    /**
    * Validates a JSON string.
    *
    * @param string $json The JSON string to validate.
    * @param int $depth Maximum depth. Must be greater than zero.
    * @param int $flags Bitmask of JSON decode options.
    * @return bool Returns true if the string is a valid JSON, otherwise false.
    */
    function json_validate($json, $depth = 512, $flags = 0) {
    if (!is_string($json)) {
    return false;
    }

    try {
    json_decode($json, false, $depth, $flags | JSON_THROW_ON_ERROR);
    return true;
    } catch (\JsonException $e) {
    return false;
    }
    }
    }
    ```

    Key Improvements:

    - String Check: Added a validation to ensure the input is a string.
    - Error Handling: Utilizes try-catch to effectively catch and handle JsonException.
    - Backward Compatibility: Safely integrable in older PHP versions, automatically deferring to native functionality in PHP 8.3+.
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