PHP `is_json`

// Check for valid JSON string // Usage: `if (is_json($text)) { … }` function is_json($x) { if (!is_string($x) || trim($x) === "") return false; return $x === 'null' || ( // Maybe an empty string, array or object $x === '""' || $x === '[]' || $x === '{}' || // Maybe an encoded JSON string $x[0] === '"' && substr($x, -1) === '"' || // Maybe a numeric array $x[0] === '[' && substr($x, -1) === ']' || // Maybe an associative array $x[0] === '{' && substr($x, -1) === '}' ) && json_decode($x) !== null; }
Check if string is a valid JSON.

1 Response

I added that because `null` is also a valid JSON. And PHP `json_decode` simply return the string into `null` if it is invalid or broken.

• Values true, false and null are returned as TRUE, FALSE and NULL respectively.
• NULL is returned if the JSON cannot be decoded or if the encoded data is deeper than the recursion limit.

http://php.net/manual/en/function.json-decode.php#refsect1-function.json-decode-returnvalues

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