tweeper.php: factor out an html_to_xml() function from the tweep() method

[tweeper.git] / tweeper.php

diff --git a/tweeper.php b/tweeper.php
old mode 100755 (executable)
new mode 100644 (file)
index 3b8fb2d..524928a
--- a/tweeper.php
+++ b/tweeper.php
@@ -1,75 +1,207 @@
 <?php
 /*
  * tweeper - a Twitter to RSS web scraper
 <?php
 /*
  * tweeper - a Twitter to RSS web scraper

- * 
- * Copyright (C) 2013  Antonio Ospite <ospite@studenti.unina.it>
- * 
+ *
+ * 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 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.
  * 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/>.
  */
 
 date_default_timezone_set('UTC');
 
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 date_default_timezone_set('UTC');
 

-function str_to_gmdate($date)
-{
-  $timestamp = strtotime($date);
-  return epoch_to_gmdate($timestamp);
-}
+class Tweeper {

 
 

-function epoch_to_gmdate($timestamp)
-{
-  return gmdate('D, d M Y H:i:s', $timestamp) . ' GMT';
-}
+  private static $USER_AGENT = "Mozilla/5.0 (Windows NT 6.1; rv:22.0) Gecko/20130405 Firefox/22.0";

 
 

-class Tweeper {
+  public function __construct($generate_enclosure = FALSE) {
+    $this->generate_enclosure = $generate_enclosure;
+  }

 
 

-  private $USER_AGENT = "Mozilla/5.0 (Windows NT 6.1; rv:22.0) Gecko/20130405 Firefox/22.0";
+  public static function epoch_to_gmdate($timestamp)
+  {
+    return gmdate('D, d M Y H:i:s', $timestamp) . ' GMT';
+  }

 
 

-  public function __construct($stylesheet) {
-    $stylesheet_contents = $this->get_contents($stylesheet);
+  public static function str_to_gmdate($date)
+  {
+    $timestamp = strtotime($date);
+    return Tweeper::epoch_to_gmdate($timestamp);
+  }

 
 

-    $xslDoc = new DOMDocument();
-    $xslDoc->loadXML($stylesheet_contents);
+  private static function get_contents($url)
+  {
+    $ch = curl_init($url);
+    curl_setopt_array($ch, array(
+      CURLOPT_HEADER => FALSE,
+      CURLOPT_FOLLOWLOCATION => TRUE,  // follow http redirects to get the real URL
+      CURLOPT_RETURNTRANSFER => TRUE,
+      CURLOPT_SSL_VERIFYHOST => FALSE,
+      CURLOPT_SSL_VERIFYPEER => FALSE,
+      CURLOPT_HTTPHEADER => array('Accept-language: en'),
+      CURLOPT_USERAGENT => Tweeper::$USER_AGENT,
+    ));
+    $contents = curl_exec($ch);
+    curl_close($ch);

 
 

-    $this->xsltProcessor = new XSLTProcessor();
-    $this->xsltProcessor->registerPHPFunctions();
-    $this->xsltProcessor->importStylesheet($xslDoc);
+    return $contents;

   }
 
   }
 

-  private function get_contents($uri) {
-    # https://www.wjsams.com/c/docs/Wiki/Php-HowToSetUserAgentOnFileGetContents
-    $opts = array(
-      'http' => array(
-        'method' => "GET",
-        'header' => join(array(
-          "Accept-language: en\r\n",
-          "User-Agent: {$this->USER_AGENT}\r\n"
-        ))
-      )
+  private static function get_info($url)
+  {
+    $ch = curl_init($url);
+    curl_setopt_array($ch, array(
+      CURLOPT_HEADER => TRUE,
+      CURLOPT_NOBODY => TRUE,
+      CURLOPT_FOLLOWLOCATION => TRUE,  // follow http redirects to get the real URL
+      CURLOPT_RETURNTRANSFER => TRUE,
+      CURLOPT_SSL_VERIFYHOST => FALSE,
+      CURLOPT_SSL_VERIFYPEER => FALSE,
+      CURLOPT_USERAGENT => Tweeper::$USER_AGENT,
+    ));
+    curl_exec($ch);
+    $url_info = curl_getinfo($ch);
+    curl_close($ch);
+
+    return $url_info;
+  }
+
+  public static function generate_enclosure($url)
+  {
+    $supported_content_types = array(
+      "application/ogg",
+      "audio/aac",
+      "audio/mp4",
+      "audio/mpeg",
+      "audio/ogg",
+      "audio/vorbis",
+      "audio/wav",
+      "audio/webm",
+      "audio/x-midi",
+      "image/gif",
+      "image/jpeg",
+      "video/avi",
+      "video/mp4",
+      "video/mpeg",
+      "video/ogg",

     );
 
     );
 

-    $context = stream_context_create($opts);
-    $contents = file_get_contents($uri, false, $context);
-    return $contents;
+    $url_info = Tweeper::get_info($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 '';
+    }
+
+    $dom = new DomDocument();
+    $enc = $dom->createElement('enclosure');
+    $enc->setAttribute('url', $url_info['url']);
+    $enc->setAttribute('length', $url_info['download_content_length']);
+    $enc->setAttribute('type', $url_info['content_type']);
+
+    $dom->appendChild($enc);
+
+    return $dom->saveXML($enc);
+  }
+
+  /* Mimic the message from libxml.c::php_libxml_ctx_error_level() */
+  private function log_xml_error($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);

   }
 
   }
 

-  public function tweep($uri) {
-    $html = $this->get_contents($uri);
+  private function load_stylesheet($host) {
+    $stylesheet = "file://" . __DIR__ . "/rss_converter_" . $host . ".xsl";
+    if (FALSE === file_exists($stylesheet)) {
+      trigger_error("Conversion to RSS not supported: $host", E_USER_ERROR);
+      return NULL;
+    }
+
+    $stylesheet_contents = $this->get_contents($stylesheet);
+
+    $xslDoc = new DOMDocument();
+    $xslDoc->loadXML($stylesheet_contents);
+
+    $xsltProcessor = new XSLTProcessor();
+    $xsltProcessor->registerPHPFunctions();
+    $xsltProcessor->setParameter('', 'generateEnclosure', $this->generate_enclosure);
+    $xsltProcessor->importStylesheet($xslDoc);

 
 

+    return $xsltProcessor;
+  }
+
+  private function html_to_xml($html) {

     $xmlDoc = new DOMDocument();
     $xmlDoc = new DOMDocument();

+
+    // Handle warnings and errors when loading invalid HTML.
+    $xml_errors_value = libxml_use_internal_errors(true);

     $xmlDoc->loadHTML($html);
     $xmlDoc->loadHTML($html);

+    foreach (libxml_get_errors() as $xml_error) {
+      $this->log_xml_error($xml_error);
+    }
+    libxml_clear_errors();
+    libxml_use_internal_errors($xml_errors_value);
+
+    return $xmlDoc;
+  }

 
 

-    $output = $this->xsltProcessor->transformToXML($xmlDoc);
+  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;
+    }
+
+    $xsltProcessor = $this->load_stylesheet($url["host"]);
+    if (NULL === $xsltProcessor) {
+      return NULL;
+    }
+
+    $html = $this->get_contents($src_url);
+    if (FALSE === $html) {
+      return NULL;
+    }
+
+    $xmlDoc = $this->html_to_xml($html);
+    if (NULL === $xmlDoc) {
+      return NULL;
+    }
+
+    $output = $xsltProcessor->transformToXML($xmlDoc);

 
     if (FALSE === $output) {
       trigger_error('XSL transformation failed.', E_USER_ERROR);
 
     if (FALSE === $output) {
       trigger_error('XSL transformation failed.', E_USER_ERROR);


@@ -82,32 +214,71 @@ class Tweeper {
 function usage($argv)
 {
   if (php_sapi_name() != 'cli')
 function usage($argv)
 {
   if (php_sapi_name() != 'cli')

-    $usage = htmlentities("{$_SERVER['SCRIPT_NAME']}?src_url=<src_url>");
+    $usage = htmlentities("{$_SERVER['SCRIPT_NAME']}?src_url=<src_url>&generate_enclosure=<0|1>");

   else
   else

-    $usage = "{$argv[0]} <src_url>\n";
+    $usage = "{$argv[0]} [-e|-h|--help] <src_url>\n";

 
   return "usage: $usage";
 }
 
 
   return "usage: $usage";
 }
 

-if (isset($_GET['src_url'])) {
-  $src_url = $_GET['src_url'];
-} else if (isset($argv[1])) {
-  if ($argv[1] == "-h" || $argv[1] == "--help") {
-    echo usage($argv);
-    return 0;
+function parse_options_cli($argv, $argc)
+{
+  $options = array(
+    'generate_enclosure' => FALSE
+  );
+
+  if ($argc < 2)
+    return $options;
+
+  $cli_options = getopt("eh", array("help"));
+  foreach ($cli_options as $opt => $val) {
+    switch ($opt) {
+    case 'e':
+      $options['generate_enclosure'] = TRUE;
+      break;
+    case 'h':
+    case 'help':
+      echo usage($argv);
+      exit(0);
+    default:
+      fwrite(STDERR, usage($argv));
+      exit(1);
+    }

   }
   }

-  $src_url = $argv[1];
-} else {
-  die(usage($argv));
+
+  $options['src_url'] = $argv[count($cli_options) + 1];
+
+  return $options;
+}
+
+function parse_options_query_string()
+{
+  $options = array(
+    'generate_enclosure' => FALSE
+  );
+
+  if (isset($_GET['src_url']))
+    $options['src_url'] = $_GET['src_url'];
+
+  if (isset($_GET['generate_enclosure']))
+    $options['generate_enclosure'] = $_GET['generate_enclosure'] == 1;
+
+  return $options;

 }
 
 }
 

-$url = parse_url($src_url);
-if (FALSE === $url || empty($url["host"]))
-  die("Invalid url: $url\n");

 
 

-$stylesheet = __DIR__ . "/rss_converter_" . $url["host"] . ".xsl";
-if (FALSE === file_exists($stylesheet))
-  die("Conversion to RSS not supported: {$url["host"]}\n");
+if (php_sapi_name() != 'cli') {
+  $options = parse_options_query_string();
+  $ERROR_STREAM = fopen('php://output', 'w');
+} else {
+  $options = parse_options_cli($argv, $argc);
+  $ERROR_STREAM = fopen('php://stderr', 'w');
+}
+
+if (!isset($options['src_url'])) {
+  fwrite($ERROR_STREAM, usage($argv));
+  exit(1);
+}

 
 

-$tweeper = new Tweeper($stylesheet);
-echo $tweeper->tweep($src_url);
+$tweeper = new Tweeper($options['generate_enclosure']);
+echo $tweeper->tweep($options['src_url']);