humanizeHtml($contentHtml); // humanizes /
prose, keeps headings
* $score = $ud->detect($humanHtml); // ['result'=>0-100 AI%, 'human'=>0-100]
*/
class Undetectable {
const HUMANIZE_URL = 'https://humanize.undetectable.ai';
const DETECT_URL = 'https://ai-detect.undetectable.ai';
const MIN_CHARS = 50; // humanizer minimum input length
private $apiKey;
public function __construct($apiKey = null) {
$this->apiKey = $apiKey ?: (defined('UNDETECTABLE_API_KEY') ? UNDETECTABLE_API_KEY : '');
}
/**
* Humanize a plain-text block (submit -> poll /document).
* Returns the humanized text, or the ORIGINAL text on failure/timeout
* (never null, so callers can never blank out content).
*/
public function humanize($text, $opts = array(), $maxWaitSec = 120) {
$text = (string) $text;
if (strlen(trim($text)) < self::MIN_CHARS) {
return $text;
}
$payload = array(
'content' => $text,
'readability' => isset($opts['readability']) ? $opts['readability'] : 'University',
'purpose' => isset($opts['purpose']) ? $opts['purpose'] : 'Article',
// "More Human" + v11 measured ~100% -> ~7% AI in testing; "Balanced"/v2
// left it at ~100%. Evasion is the goal, so default to the strong combo.
'strength' => isset($opts['strength']) ? $opts['strength'] : 'More Human',
'model' => isset($opts['model']) ? $opts['model'] : 'v11',
);
$sub = $this->request(self::HUMANIZE_URL . '/submit', $payload, true);
$id = isset($sub['id']) ? $sub['id'] : null;
if (!$id) {
return $text;
}
$waited = 0;
while ($waited < $maxWaitSec) {
sleep(5);
$waited += 5;
$doc = $this->request(self::HUMANIZE_URL . '/document', array('id' => $id), true);
if (!empty($doc['output'])) {
return $doc['output'];
}
}
return $text;
}
/**
* Run AI detection on text (submit -> poll /query).
* HTML is stripped first; ~200+ words recommended for accuracy.
* Returns array('result'=>float 0-100 AI-likelihood, 'human'=>float) or null.
*/
public function detect($text) {
$text = trim(strip_tags((string) $text));
if ($text === '') {
return null;
}
$payload = array(
'text' => $text,
'key' => $this->apiKey,
'model' => 'xlm_ud_detector',
'retry_count' => 0,
);
$sub = $this->request(self::DETECT_URL . '/detect', $payload, false);
$id = isset($sub['id']) ? $sub['id'] : null;
if (!$id) {
return null;
}
for ($i = 0; $i < 15; $i++) {
sleep(2);
$q = $this->request(self::DETECT_URL . '/query', array('id' => $id), false);
if (isset($q['status']) && $q['status'] === 'done') {
return array(
'result' => isset($q['result']) ? (float) $q['result'] : null,
'human' => isset($q['result_details']['human']) ? (float) $q['result_details']['human'] : null,
);
}
}
return null;
}
/**
* Humanize the prose of an HTML article ( and
blocks only),
* leaving headings and other markup intact so SEO keywords in
* H1/H2/H3 are preserved.
*/
public function humanizeHtml($html, $opts = array()) {
$self = $this;
return preg_replace_callback(
'/<(p|li)\b([^>]*)>(.*?)<\/\1>/is',
function ($m) use ($self, $opts) {
$plain = trim(strip_tags($m[3]));
if (strlen($plain) < Undetectable::MIN_CHARS) {
return $m[0];
}
$human = $self->humanize($plain, $opts);
return '<' . $m[1] . $m[2] . '>' . $human . '';
},
$html
);
}
/** Remaining word credits, or null on failure. */
public function credits() {
$res = $this->request(self::DETECT_URL . '/check-user-credits', null, true, 'GET');
return isset($res['credits']) ? (float) $res['credits'] : null;
}
/**
* @param bool $headerAuth true => send apikey header; false => key is in the body.
*/
private function request($url, $payload, $headerAuth, $method = 'POST') {
$ch = curl_init();
$headers = array('Content-Type: application/json', 'accept: application/json');
if ($headerAuth && $this->apiKey) {
$headers[] = 'apikey: ' . $this->apiKey;
}
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_TIMEOUT, 120);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
if (strtoupper($method) === 'POST') {
$json = json_encode($payload);
if ($json === false && is_array($payload)) {
// Content stored as latin1 (e.g. smart quotes) is invalid UTF-8 and
// makes json_encode return false -> empty body -> silent API no-op.
// Coerce strings to UTF-8 so the call actually goes through.
array_walk_recursive($payload, function (&$v) {
if (is_string($v) && !mb_check_encoding($v, 'UTF-8')) {
$v = mb_convert_encoding($v, 'UTF-8', 'ISO-8859-1');
}
});
$json = json_encode($payload);
}
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, $json);
}
$resp = curl_exec($ch);
curl_close($ch);
if ($resp === false) {
return array();
}
$data = json_decode($resp, true);
return is_array($data) ? $data : array();
}
}