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<?php
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
use XRay\Formats;
class Parse {
public $http;
public function __construct() {
$this->http = new p3k\HTTP();
}
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');
$response->setContent(json_encode($params));
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;
}
$url = $request->get('url');
if(!$url) {
return $this->respond($response, 400, [
'error' => 'missing_url',
'error_description' => 'Provide a URL to fetch'
]);
}
// 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
$result = $this->http->get($url);
if($result['error']) {
return $this->respond($response, 400, [
'error' => $result['error'],
'error_description' => $result['error_description']
]);
}
// attempt to parse the page as HTML
$doc = new DOMDocument();
@$doc->loadHTML(self::toHtmlEntities($result['body']));
if(!$doc) {
return $this->respond($response, 400, [
'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) {
$url = $href->getAttribute('href');
if($target) {
# target parameter was provided
if($url == $target) {
$found[$url] = null;
}
}
}
if(!$found) {
return $this->respond($response, 400, [
'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'], $url);
if($mf2 && count($mf2['items']) > 0) {
$data = Formats\Mf2::parse($mf2, $url, $this->http);
if($data) {
return $this->respond($response, 200, [
'data' => $data,
]);
}
}
// TODO: look for other content like OEmbed or other known services later
return $this->respond($response, 400, [
'error' => 'no_content',
'error_description' => 'No usable content could be found at the given URL'
]);
}
}