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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 = 120;
private $_pretty = false;
public function __construct() {
$this->http = new p3k\HTTP();
if(Config::$cache && 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);
// Check if this is a Twitter URL and if they've provided API credentials, use the API
if(preg_match('/https?:\/\/(?:mobile\.twitter\.com|twitter\.com|twtr\.io)\/(?:[a-z0-9_\/!#]+statuse?s?\/([0-9]+)|([a-zA-Z0-9_]+))/i', $url, $match)) {
return $this->parseTwitterURL($request, $response, $url, $match);
}
// Now fetch the URL and check for any curl errors
// Don't cache the response if a token is used to fetch it
if($this->mc && !$request->get('token')) {
$cacheKey = 'xray-'.md5($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 {
$headers = [];
if($request->get('token')) {
$headers[] = 'Authorization: Bearer ' . $request->get('token');
}
$result = $this->http->get($url, $headers);
}
if($result['error']) {
return $this->respond($response, 200, [
'error' => $result['error'],
'error_description' => $result['error_description'],
'url' => $result['url'],
'code' => $result['code']
]);
}
if(trim($result['body']) == '') {
if($result['code'] == 410) {
// 410 Gone responses are valid and should not return an error
return $this->respond($response, 200, [
'data' => [
'type' => 'unknown'
],
'url' => $result['url'],
'code' => $result['code']
]);
}
return $this->respond($response, 200, [
'error' => 'no_content',
'error_description' => 'We did not get a response body when fetching the URL',
'url' => $result['url'],
'code' => $result['code']
]);
}
// Check for HTTP 401/403
if($result['code'] == 401) {
return $this->respond($response, 200, [
'error' => 'unauthorized',
'error_description' => 'The URL returned "HTTP 401 Unauthorized"',
'url' => $result['url'],
'code' => 401
]);
}
if($result['code'] == 403) {
return $this->respond($response, 200, [
'error' => 'forbidden',
'error_description' => 'The URL returned "HTTP 403 Forbidden"',
'url' => $result['url'],
'code' => 403
]);
}
}
// Check for known services
$host = parse_url($result['url'], PHP_URL_HOST);
if(in_array($host, ['www.instagram.com','instagram.com'])) {
list($data, $parsed) = Formats\Instagram::parse($result['body'], $result['url'], $this->http);
if($request->get('include_original'))
$data['original'] = $parsed;
$data['url'] = $result['url'];
$data['code'] = $result['code'];
return $this->respond($response, 200, $data);
}
// 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'
]);
}
$xpath = new DOMXPath($doc);
// Check for meta http equiv and replace the status code if present
foreach($xpath->query('//meta[translate(@http-equiv,\'STATUS\',\'status\')=\'status\']') as $el) {
$equivStatus = ''.$el->getAttribute('content');
if($equivStatus && is_string($equivStatus)) {
if(preg_match('/^(\d+)/', $equivStatus, $match)) {
$result['code'] = (int)$match[1];
}
}
}
// If a target parameter was provided, make sure a link to it exists on the page
if($target=$request->get('target')) {
$found = [];
if($target) {
self::xPathFindNodeWithAttribute($xpath, 'a', 'href', function($u) use($target, &$found){
if($u == $target) {
$found[$u] = null;
}
});
self::xPathFindNodeWithAttribute($xpath, 'img', 'src', function($u) use($target, &$found){
if($u == $target) {
$found[$u] = null;
}
});
self::xPathFindNodeWithAttribute($xpath, 'video', 'src', function($u) use($target, &$found){
if($u == $target) {
$found[$u] = null;
}
});
self::xPathFindNodeWithAttribute($xpath, 'audio', 'src', function($u) use($target, &$found){
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',
'url' => $result['url'],
'code' => $result['code'],
]);
}
}
// If the URL has a fragment ID, find the DOM starting at that node and parse it instead
$html = $result['body'];
$fragment = parse_url($url, PHP_URL_FRAGMENT);
if($fragment) {
$fragElement = self::xPathGetElementById($xpath, $fragment);
if($fragElement) {
$html = $doc->saveHTML($fragElement);
$foundFragment = true;
} else {
$foundFragment = false;
}
}
// Now start pulling in the data from the page. Start by looking for microformats2
$mf2 = mf2\Parse($html, $result['url']);
if($mf2 && count($mf2['items']) > 0) {
$data = Formats\Mf2::parse($mf2, $result['url'], $this->http);
if($data) {
if($fragment) {
$data['info'] = [
'found_fragment' => $foundFragment
];
}
if($request->get('include_original'))
$data['original'] = $html;
$data['url'] = $result['url']; // this will be the effective URL after following redirects
$data['code'] = $result['code'];
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',
],
'url' => $result['url'],
'code' => $result['code']
]);
}
private static function xPathFindNodeWithAttribute($xpath, $node, $attr, $callback) {
foreach($xpath->query('//'.$node.'[@'.$attr.']') as $el) {
$v = $el->getAttribute($attr);
$callback($v);
}
}
private static function xPathGetElementById($xpath, $id) {
$element = null;
foreach($xpath->query("//*[@id='$id']") as $el) {
$element = $el;
}
return $element;
}
private function parseTwitterURL(&$request, &$response, $url, $match) {
$fields = ['twitter_api_key','twitter_api_secret','twitter_access_token','twitter_access_token_secret'];
$creds = [];
foreach($fields as $f) {
if($v=$request->get($f))
$creds[$f] = $v;
}
$data = false;
if(count($creds) == 4) {
list($data, $parsed) = Formats\Twitter::parse($url, $match[1], $creds);
} elseif(count($creds) > 0) {
// If only some Twitter credentials were present, return an error
return $this->respond($response, 400, [
'error' => 'missing_parameters',
'error_description' => 'All 4 Twitter credentials must be included in the request'
]);
} else {
// Accept Tweet JSON and parse that if provided
$json = $request->get('json');
if($json) {
list($data, $parsed) = Formats\Twitter::parse($url, $match[1], null, $json);
}
// Skip parsing from the Twitter API if they didn't include credentials
}
if($data) {
if($request->get('include_original'))
$data['original'] = $parsed;
$data['url'] = $url;
$data['code'] = 200;
return $this->respond($response, 200, $data);
} else {
return $this->respond($response, 200, [
'data' => [
'type' => 'unknown'
],
'url' => $url,
'code' => 0
]);
}
}
}