simple class wrapper for encoding and decoding JSON via : http://phpfashion.com/how-to-encode-and-decode-json-in-php

classJson.php

<?php 
class Json
{
    private static $messages = array(
        JSON_ERROR_DEPTH => 'The maximum stack depth has been exceeded',
        JSON_ERROR_STATE_MISMATCH => 'Syntax error, malformed JSON',
        JSON_ERROR_CTRL_CHAR => 'Unexpected control character found',
        JSON_ERROR_SYNTAX => 'Syntax error, malformed JSON',
        5 /*JSON_ERROR_UTF8*/ => 'Invalid UTF-8 sequence',
        6 /*JSON_ERROR_RECURSION*/ => 'Recursion detected',
        7 /*JSON_ERROR_INF_OR_NAN*/ => 'Inf and NaN cannot be JSON encoded',
        8 /*JSON_ERROR_UNSUPPORTED_TYPE*/ => 'Type is not supported',
    );


    public static function encode($value)
    {
        // needed to receive 'Invalid UTF-8 sequence' error; PHP bugs #52397, #54109, #63004
        if (function_exists('ini_set')) { // ini_set is disabled on some hosts :-(
            $old = ini_set('display_errors', 0);
        }

        // needed to receive 'recursion detected' error
        set_error_handler(function($severity, $message) {
            restore_error_handler();
            throw new JsonException($message);
        });

        $json = json_encode($value);

        restore_error_handler();
        if (isset($old)) {
            ini_set('display_errors', $old);
        }
        if ($error = json_last_error()) {
            $message = isset(static::$messages[$error]) ? static::$messages[$error] : 'Unknown error';
            throw new JsonException($message, $error);
        }
        return $json;
    }


    public static function decode($json)
    {
        if (!preg_match('##u', $json)) { // workaround for PHP < 5.3.3 & PECL JSON-C
            throw new JsonException('Invalid UTF-8 sequence', 5);
        }

        $value = json_decode($json);

        if ($value === NULL
            && $json !== ''  // it doesn't clean json_last_error flag until 5.3.7
            && $json !== 'null' // in this case NULL is not failure
        ) {
            $error = json_last_error();
            $message = isset(static::$messages[$error]) ? static::$messages[$error] : 'Unknown error';
            throw new JsonException($message, $error);
        }
        return $value;
    }
}

?>