+<?php
+
+namespace Tweeper;
+
+/**
+ * @file
+ * Tweeper - a Twitter to RSS web scraper.
+ *
+ * Copyright (C) 2013-2015 Antonio Ospite <ao2@ao2.it>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+use DOMDocument;
+use XSLTProcessor;
+
+require_once 'Symfony/Component/Serializer/autoload.php';
+
+use Symfony\Component\Serializer\Serializer;
+use Symfony\Component\Serializer\Encoder\XmlEncoder;
+use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
+
+date_default_timezone_set('UTC');
+
+/**
+ * Scrape supported websites and perform conversion to RSS.
+ */
+class Tweeper {
+
+ private static $userAgent = "Mozilla/5.0 (Windows NT 6.1; rv:22.0) Gecko/20130405 Firefox/22.0";
+
+ /**
+ * Constructor sets up {@link $generate_enclosure}.
+ */
+ public function __construct($generate_enclosure = FALSE) {
+ $this->generate_enclosure = $generate_enclosure;
+ }
+
+ /**
+ * Convert numeric Epoch to the date format expected in a RSS document.
+ */
+ public static function epochToRssDate($timestamp) {
+ if (!is_numeric($timestamp) || is_nan($timestamp)) {
+ $timestamp = 0;
+ }
+
+ return gmdate(DATE_RSS, $timestamp);
+ }
+
+ /**
+ * Convert generic date string to the date format expected in a RSS document.
+ */
+ public static function strToRssDate($date) {
+ $timestamp = strtotime($date);
+ if (FALSE === $timestamp) {
+ $timestamp = 0;
+ }
+
+ return Tweeper::epochToRssDate($timestamp);
+ }
+
+ /**
+ * Convert string to UpperCamelCase.
+ */
+ public static function toUpperCamelCase($str, $delim = ' ') {
+ $str_upper = ucwords($str, $delim);
+ $str_camel_case = str_replace($delim, '', $str_upper);
+ return $str_camel_case;
+ }
+
+ /**
+ * Get the contents from a URL.
+ */
+ private static function getUrlContents($url) {
+ $ch = curl_init($url);
+ curl_setopt_array($ch, array(
+ CURLOPT_HEADER => FALSE,
+ // Follow http redirects to get the real URL.
+ CURLOPT_FOLLOWLOCATION => TRUE,
+ CURLOPT_RETURNTRANSFER => TRUE,
+ CURLOPT_SSL_VERIFYHOST => FALSE,
+ CURLOPT_SSL_VERIFYPEER => FALSE,
+ CURLOPT_HTTPHEADER => array('Accept-language: en'),
+ CURLOPT_USERAGENT => Tweeper::$userAgent,
+ ));
+ $contents = curl_exec($ch);
+ if (FALSE === $contents) {
+ trigger_error(curl_error($ch));
+ }
+ curl_close($ch);
+
+ return $contents;
+ }
+
+ /**
+ * Get the headers from a URL.
+ */
+ private static function getUrlInfo($url) {
+ $ch = curl_init($url);
+ curl_setopt_array($ch, array(
+ CURLOPT_HEADER => TRUE,
+ CURLOPT_NOBODY => TRUE,
+ // Follow http redirects to get the real URL.
+ CURLOPT_FOLLOWLOCATION => TRUE,
+ CURLOPT_RETURNTRANSFER => TRUE,
+ CURLOPT_SSL_VERIFYHOST => FALSE,
+ CURLOPT_SSL_VERIFYPEER => FALSE,
+ CURLOPT_USERAGENT => Tweeper::$userAgent,
+ ));
+ curl_exec($ch);
+ $url_info = curl_getinfo($ch);
+ if (FALSE === $url_info) {
+ trigger_error(curl_error($ch));
+ }
+ curl_close($ch);
+
+ return $url_info;
+ }
+
+ /**
+ * Generate an RSS <enclosure/> element.
+ */
+ public static function generateEnclosure($url) {
+ $supported_content_types = array(
+ "application/octet-stream",
+ "application/ogg",
+ "application/pdf",
+ "audio/aac",
+ "audio/mp4",
+ "audio/mpeg",
+ "audio/ogg",
+ "audio/vorbis",
+ "audio/wav",
+ "audio/webm",
+ "audio/x-midi",
+ "image/gif",
+ "image/jpeg",
+ "image/png",
+ "video/avi",
+ "video/mp4",
+ "video/mpeg",
+ "video/ogg",
+ );
+
+ $url_info = Tweeper::getUrlInfo($url);
+
+ $supported = in_array($url_info['content_type'], $supported_content_types);
+ if (!$supported) {
+ error_log("Unsupported enclosure content type \"" . $url_info['content_type'] . "\" for URL: " . $url_info['url']);
+ return '';
+ }
+
+ // The RSS specification says that the enclosure element URL must be http.
+ // See http://sourceforge.net/p/feedvalidator/bugs/72/
+ $http_url = preg_replace("/^https/", "http", $url_info['url']);
+
+ $dom = new DOMDocument();
+ $enc = $dom->createElement('enclosure');
+ $enc->setAttribute('url', $http_url);
+ $enc->setAttribute('length', $url_info['download_content_length']);
+ $enc->setAttribute('type', $url_info['content_type']);
+
+ return $enc;
+ }
+
+ /**
+ * Mimic the message from libxml.c::php_libxml_ctx_error_level()
+ */
+ private static function logXmlError($error) {
+ $output = "";
+
+ switch ($error->level) {
+ case LIBXML_ERR_WARNING:
+ $output .= "Warning $error->code: ";
+ break;
+
+ case LIBXML_ERR_ERROR:
+ $output .= "Error $error->code: ";
+ break;
+
+ case LIBXML_ERR_FATAL:
+ $output .= "Fatal Error $error->code: ";
+ break;
+ }
+
+ $output .= trim($error->message);
+
+ if ($error->file) {
+ $output .= " in $error->file";
+ }
+ else {
+ $output .= " in Entity,";
+ }
+
+ $output .= " line $error->line";
+
+ error_log($output);
+ }
+
+ /**
+ * Convert json to XML.
+ */
+ private static function jsonToXml($json, $root_node_name) {
+ // Apparently the ObjectNormalizer used afterwards is not able to handle
+ // the stdClass object created by json_decode() with the default setting
+ // $assoc = false; so use $assoc = true.
+ $data = json_decode($json, $assoc = TRUE);
+ if (!$data) {
+ return NULL;
+ }
+
+ $encoder = new XmlEncoder();
+ $normalizer = new ObjectNormalizer();
+ $serializer = new Serializer(array($normalizer), array($encoder));
+
+ $serializer_options = array(
+ 'xml_encoding' => "UTF-8",
+ 'xml_format_output' => TRUE,
+ 'xml_root_node_name' => $root_node_name,
+ );
+
+ $xml_data = $serializer->serialize($data, 'xml', $serializer_options);
+ if (!$xml_data) {
+ trigger_error("Cannot serialize data", E_USER_ERROR);
+ return NULL;
+ }
+
+ return $xml_data;
+ }
+
+ /**
+ * Convert the Instagram content to XML.
+ */
+ private function getXmlInstagramCom($html) {
+ // Extract the json data from the html code.
+ $json_match_expr = '/window._sharedData = (.*);/';
+ $ret = preg_match($json_match_expr, $html, $matches);
+ if ($ret !== 1) {
+ trigger_error("Cannot match expression: $json_match_expr\n", E_USER_ERROR);
+ return NULL;
+ }
+
+ return Tweeper::jsonToXml($matches[1], 'instagram');
+ }
+
+ /**
+ * Make the Facebook HTML processable.
+ */
+ private function preprocessHtmlFacebookCom($html) {
+ $html = str_replace('<!--', '', $html);
+ $html = str_replace('-->', '', $html);
+ return $html;
+ }
+
+ /**
+ * Convert the HTML retrieved from the site to XML.
+ */
+ private function htmlToXml($html, $host) {
+ $xmlDoc = new DOMDocument();
+
+ // Handle warnings and errors when loading invalid HTML.
+ $xml_errors_value = libxml_use_internal_errors(TRUE);
+
+ // If there is a host-specific method to get the XML data, use it!
+ $get_xml_host_method = 'getXml' . Tweeper::toUpperCamelCase($host, '.');
+ if (method_exists($this, $get_xml_host_method)) {
+ $xml_data = call_user_func_array(array($this, $get_xml_host_method), array($html));
+ $xmlDoc->loadXML($xml_data);
+ }
+ else {
+ $xmlDoc->loadHTML($html);
+ }
+
+ foreach (libxml_get_errors() as $xml_error) {
+ Tweeper::logXmlError($xml_error);
+ }
+ libxml_clear_errors();
+ libxml_use_internal_errors($xml_errors_value);
+
+ return $xmlDoc;
+ }
+
+ /**
+ * Load a stylesheet if the web site is supported.
+ */
+ private function loadStylesheet($host) {
+ $stylesheet = "file://" . __DIR__ . "/rss_converter_" . $host . ".xsl";
+ if (FALSE === file_exists($stylesheet)) {
+ trigger_error("Conversion to RSS not supported for $host ($stylesheet not found)", E_USER_ERROR);
+ return NULL;
+ }
+
+ $stylesheet_contents = Tweeper::getUrlContents($stylesheet);
+
+ $xslDoc = new DOMDocument();
+ $xslDoc->loadXML($stylesheet_contents);
+
+ $xsltProcessor = new XSLTProcessor();
+ $xsltProcessor->registerPHPFunctions();
+ $xsltProcessor->setParameter('', 'generate-enclosure', $this->generate_enclosure);
+ $xsltProcessor->importStylesheet($xslDoc);
+
+ return $xsltProcessor;
+ }
+
+ /**
+ * Convert the site content to RSS.
+ */
+ public function tweep($src_url) {
+ $url = parse_url($src_url);
+ if (FALSE === $url || empty($url["host"])) {
+ trigger_error("Invalid URL: $src_url", E_USER_ERROR);
+ return NULL;
+ }
+
+ $scheme = $url["scheme"];
+ if (!in_array($scheme, array("http", "https"))) {
+ trigger_error("unsupported scheme: $scheme", E_USER_ERROR);
+ return NULL;
+ }
+
+ // Strip the leading www. to be more forgiving on input URLs.
+ $host = preg_replace('/^www\./', '', $url["host"]);
+
+ $xsltProcessor = $this->loadStylesheet($host);
+ if (NULL === $xsltProcessor) {
+ return NULL;
+ }
+
+ $html = Tweeper::getUrlContents($src_url);
+ if (FALSE === $html) {
+ return NULL;
+ }
+
+ $preprocess_html_host_method = 'preprocessHtml' . Tweeper::toUpperCamelCase($host, '.');
+ if (method_exists($this, $preprocess_html_host_method)) {
+ $html = call_user_func_array(array($this, $preprocess_html_host_method), array($html));
+ }
+
+ $xmlDoc = $this->htmlToXml($html, $host);
+ if (NULL === $xmlDoc) {
+ return NULL;
+ }
+
+ $output = $xsltProcessor->transformToXML($xmlDoc);
+
+ if (FALSE === $output) {
+ trigger_error('XSL transformation failed.', E_USER_ERROR);
+ return NULL;
+ }
+ return $output;
+ }
+
+}
projects / tweeper.git / commitdiff