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<?php
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
use XRay\Formats;
class Parse {
public $http;
public $mc;
private $_cacheTime = 300;
private $_pretty = false;
public function __construct() {
$this->http = new p3k\HTTP();
if(class_exists('Memcache')) {
$this->mc = new Memcache();
$this->mc->addServer('127.0.0.1');
}
}
public static function debug($msg, $header='X-Parse-Debug') {
syslog(LOG_INFO, $msg);
if(array_key_exists('REMOTE_ADDR', $_SERVER))
header($header . ": " . $msg);
}
private function respond(Response $response, $code, $params, $headers=[]) {
$response->setStatusCode($code);
foreach($headers as $k=>$v) {
$response->headers->set($k, $v);
}
$response->headers->set('Content-Type', 'application/json');
$opts = JSON_UNESCAPED_SLASHES;
if($this->_pretty) $opts += JSON_PRETTY_PRINT;
$response->setContent(json_encode($params, $opts)."\n");
return $response;
}
private static function toHtmlEntities($input) {
return mb_convert_encoding($input, 'HTML-ENTITIES', mb_detect_encoding($input));
}
public function parse(Request $request, Response $response) {
if($request->get('timeout')) {
// We might make 2 HTTP requests, so each request gets half the desired timeout
$this->http->timeout = $request->get('timeout') / 2;
}
if($request->get('max_redirects')) {
$this->http->max_redirects = (int)$request->get('max_redirects');
}
if($request->get('pretty')) {
$this->_pretty = true;
}
$url = $request->get('url');
$html = $request->get('html');
if(!$url && !$html) {
return $this->respond($response, 400, [
'error' => 'missing_url',
'error_description' => 'Provide a URL or HTML to fetch'
]);
}
if($html) {
// If HTML is provided in the request, parse that, and use the URL provided as the base URL for mf2 resolving
$result['body'] = $html;
$result['url'] = $url;
} else {
// Attempt some basic URL validation
$scheme = parse_url($url, PHP_URL_SCHEME);
if(!in_array($scheme, ['http','https'])) {
return $this->respond($response, 400, [
'error' => 'invalid_url',
'error_description' => 'Only http and https URLs are supported'
]);
}
$host = parse_url($url, PHP_URL_HOST);
if(!$host) {
return $this->respond($response, 400, [
'error' => 'invalid_url',
'error_description' => 'The URL provided was not valid'
]);
}
$url = \normalize_url($url);
// Now fetch the URL and check for any curl errors
if($this->mc) {
$cacheKey = 'xray-'.md5($url);
if($cached=$this->mc->get($cacheKey)) {
$result = json_decode($cached, true);
self::debug('using HTML from cache', 'X-Cache-Debug');
} else {
$result = $this->http->get($url);
$cacheData = json_encode($result);
// App Engine limits the size of cached items, so don't cache ones larger than that
if(strlen($cacheData) < 1000000)
$this->mc->set($cacheKey, $cacheData, MEMCACHE_COMPRESSED, $this->_cacheTime);
}
} else {
$result = $this->http->get($url);
}
if($result['error']) {
return $this->respond($response, 200, [
'error' => $result['error'],
'error_description' => $result['error_description']
]);
}
if(trim($result['body']) == '') {
return $this->respond($response, 200, [
'error' => 'no_content',
'error_description' => 'We did not get a response body when fetching the URL'
]);
}
}
// attempt to parse the page as HTML
$doc = new DOMDocument();
@$doc->loadHTML(self::toHtmlEntities($result['body']));
if(!$doc) {
return $this->respond($response, 200, [
'error' => 'invalid_content',
'error_description' => 'The document could not be parsed as HTML'
]);
}
// If a target parameter was provided, make sure a link to it exists on the page
if($target=$request->get('target')) {
$xpath = new DOMXPath($doc);
$found = [];
foreach($xpath->query('//a[@href]') as $href) {
$u = $href->getAttribute('href');
if($target) {
# target parameter was provided
if($u == $target) {
$found[$u] = null;
}
}
}
if(!$found) {
return $this->respond($response, 200, [
'error' => 'no_link_found',
'error_description' => 'The source document does not have a link to the target URL'
]);
}
}
// Now start pulling in the data from the page. Start by looking for microformats2
$mf2 = mf2\Parse($result['body'], $result['url']);
if($mf2 && count($mf2['items']) > 0) {
$data = Formats\Mf2::parse($mf2, $result['url'], $this->http);
if($data) {
return $this->respond($response, 200, $data);
}
}
// TODO: look for other content like OEmbed or other known services later
return $this->respond($response, 200, [
'data' => [
'type' => 'unknown',
]
]);
}
}