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<?php /** * Checks whether a string is valid json. * * @param string $string * @return boolean */ function json_is($string) { try { // try to decode string json_decode($string); } catch (ErrorException $e) { // exception has been caught which means argument wasn't a string and thus is definitely no json. return FALSE; } // check if error occured return (json_last_error() == JSON_ERROR_NONE); } // Make sure the string is not empty and is, in fact, a string. An empty string is not valid JSON. function isJson($string, $assoc = false) { if(!empty($string) && is_string($string)) { json_decode($string, $assoc); return (json_last_error() == JSON_ERROR_NONE); // return json_decode($str) != null; } return false; } $a=['arraiii'=>['dentro'=>234]]; $b=json_encode($a); $c=''; var_dump(isJson($c));
Output for 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.10, 7.2.0 - 7.2.33, 7.3.12 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
bool(false)
Output for 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29
Parse error: syntax error, unexpected '[' in /in/4Q492 on line 63
Process exited with code 255.
Output for 5.0.0 - 5.0.5
Parse error: parse error, unexpected '[' in /in/4Q492 on line 63
Process exited with code 255.
Output for 4.4.2 - 4.4.9
Parse error: syntax error, unexpected '{' in /in/4Q492 on line 12
Process exited with code 255.
Output for 4.3.0 - 4.3.1, 4.3.5 - 4.3.11, 4.4.0 - 4.4.1
Parse error: parse error, unexpected '{' in /in/4Q492 on line 12
Process exited with code 255.
Output for 4.3.2 - 4.3.4
Parse error: parse error in /in/4Q492 on line 12
Process exited with code 255.

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