tweeper.1.asciidoc: document how to use the PHP built-in web server

[tweeper.git] / tweeper.php

diff --git a/tweeper.php b/tweeper.php
index 74dc14f..a9fce9b 100644 (file)
--- a/tweeper.php
+++ b/tweeper.php
@@ -1,134 +1,279 @@
 <?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/>.
  */
 
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 

+require_once 'XML/Serializer.php';
+

 date_default_timezone_set('UTC');
 
 date_default_timezone_set('UTC');
 

-define('USER_AGENT', 'Mozilla/5.0 (Windows NT 6.1; rv:22.0) Gecko/20130405 Firefox/22.0');
+class Tweeper {
+
+  private static $USER_AGENT = "Mozilla/5.0 (Windows NT 6.1; rv:22.0) Gecko/20130405 Firefox/22.0";

 
 

-function get_url_info($url)
-{
-  $ch = curl_init($url);
-  curl_setopt_array($ch, array(
+  public function __construct($generate_enclosure = FALSE) {
+    $this->generate_enclosure = $generate_enclosure;
+  }
+
+  public static function epoch_to_gmdate($timestamp)
+  {
+    if (!is_numeric($timestamp) || is_nan($timestamp)) {
+      $timestamp = 0;
+    }
+
+    return gmdate('D, d M Y H:i:s', $timestamp) . ' GMT';
+  }
+
+  public static function str_to_gmdate($date)
+  {
+    $timestamp = strtotime($date);
+    if (FALSE === $timestamp) {
+      $timestamp = 0;
+    }
+
+    return Tweeper::epoch_to_gmdate($timestamp);
+  }
+
+  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);
+
+    return $contents;
+  }
+
+  private static function get_info($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_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 => USER_AGENT,
-  ));
-  curl_exec($ch);
-  $url_info = curl_getinfo($ch);;
-  curl_close($ch);
+      CURLOPT_USERAGENT => Tweeper::$USER_AGENT,
+    ));
+    curl_exec($ch);
+    $url_info = curl_getinfo($ch);
+    curl_close($ch);

 
 

-  return $url_info;
-}
+    return $url_info;
+  }

 
 

-function generate_enclosure($url)
-{
-  $supported_content_types = array(
-    "application/ogg",
-    "audio/aac",
-    "audio/mp4",
-    "audio/mpeg",
-    "audio/vorbis",
-    "audio/wav",
-    "audio/webm",
-    "audio/x-midi",
-    "image/gif",
-    "image/jpeg",
-    "video/avi",
-    "video/mp4",
-    "video/mpeg",
-    "video/ogg",
-  );
+  public static function generate_enclosure($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",
+    );
+
+    // 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);
+
+    $url_info = Tweeper::get_info($http_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']);

 
 

-  $url_info = get_url_info($url);
+    $dom->appendChild($enc);

 
 

-  $supported = in_array($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 '';
+    return $dom->saveXML($enc);

   }
 
   }
 

-  $dom = new DomDocument();
-  $enc = $dom->createElement('enclosure');
-  $enc->setAttribute('url', $url_info['url']);
-  $enc->setAttribute('length', $url_info['download_content_length']);
-  $enc->setAttribute('type', $url_info['content_type']);
+  /* Mimic the message from libxml.c::php_libxml_ctx_error_level() */
+  private function log_xml_error($error) {
+    $output = "";

 
 

-  $dom->appendChild($enc);
+    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;
+    }

 
 

-  return $dom->saveXML($enc);
-}
+    $output .= trim($error->message);

 
 

+    if ($error->file) {
+      $output .= " in $error->file";
+    } else {
+      $output .= " in Entity,";
+    }

 
 

-class Tweeper {
+    $output .=" line $error->line";
+
+    error_log($output);
+  }
+
+  private function load_stylesheet($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;
+    }

 
 

-  public function __construct($stylesheet, $generate_enclosure = FALSE) {

     $stylesheet_contents = $this->get_contents($stylesheet);
 
     $xslDoc = new DOMDocument();
     $xslDoc->loadXML($stylesheet_contents);
 
     $stylesheet_contents = $this->get_contents($stylesheet);
 
     $xslDoc = new DOMDocument();
     $xslDoc->loadXML($stylesheet_contents);
 

-    $this->xsltProcessor = new XSLTProcessor();
-    $this->xsltProcessor->registerPHPFunctions();
-    $this->xsltProcessor->setParameter('', 'generateEnclosure', $generate_enclosure);
-    $this->xsltProcessor->importStylesheet($xslDoc);
-  }
+    $xsltProcessor = new XSLTProcessor();
+    $xsltProcessor->registerPHPFunctions();
+    $xsltProcessor->setParameter('', 'generateEnclosure', $this->generate_enclosure);
+    $xsltProcessor->importStylesheet($xslDoc);

 
 

-  public static function epoch_to_gmdate($timestamp)
-  {
-    return gmdate('D, d M Y H:i:s', $timestamp) . ' GMT';
+    return $xsltProcessor;

   }
 
   }
 

-  public static function str_to_gmdate($date)
-  {
-    $timestamp = strtotime($date);
-    return Tweeper::epoch_to_gmdate($timestamp);
-  }
+  private function json_to_xml($html, $json_match_expr, $rootName) {
+    // pre-process, convert json to XML
+    $ret = preg_match($json_match_expr, $html, $matches);
+    if ($ret !== 1) {
+      trigger_error("Cannot match expression: $json_match_expr\n", E_USER_ERROR);
+      return NULL;
+    }

 
 

-  private static 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: {" + USER_AGENT + "}\r\n"
-        ))
-      )
+    $data = json_decode($matches[1]);
+    if (!$data) {
+      return NULL;
+    }
+
+    $serializer_options = array (
+      'addDecl' => TRUE,
+      'encoding' => "UTF-8",
+      'indent' => '  ',
+      'rootName' => $rootName,

     );
 
     );
 

-    $context = stream_context_create($opts);
-    $contents = file_get_contents($uri, false, $context);
-    return $contents;
+    $serializer = new XML_Serializer($serializer_options);
+
+    $status = $serializer->serialize($data);
+    if (PEAR::isError($status)) {
+      trigger_error($status->getMessage(), E_USER_ERROR);
+      return NULL;
+    }
+
+    return $serializer->getSerializedData();

   }
 
   }
 

-  public function tweep($uri) {
-    $html = Tweeper::get_contents($uri);
+  private function get_xml_instagram_com($html) {
+    return $this->json_to_xml($html, '/window._sharedData = (.*);/', 'instagram');
+  }
+
+  private function preprocess_html_facebook_com($html) {
+    $html = str_replace('<!--', '', $html);
+    $html = str_replace('-->', '', $html);
+    return $html;
+  }

 
 

+  private function html_to_xml($html, $host) {

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

-    $xmlDoc->loadHTML($html);

 
 

-    $output = $this->xsltProcessor->transformToXML($xmlDoc);
+    // 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 = 'get_xml_' . str_replace(".", "_", $host);
+    if (method_exists($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) {
+      $this->log_xml_error($xml_error);
+    }
+    libxml_clear_errors();
+    libxml_use_internal_errors($xml_errors_value);
+
+    return $xmlDoc;
+  }
+
+  public function tweep($src_url) {
+    $url = parse_url($src_url);
+    if (FALSE === $url || empty($url["host"])) {
+      trigger_error("Invalid url: $src_url", E_USER_ERROR);
+      return NULL;
+    }
+
+    // Strip the leading www. to be more forgiving on input URLs
+    $host = preg_replace('/^www\./', '', $url["host"]);
+
+    $xsltProcessor = $this->load_stylesheet($host);
+    if (NULL === $xsltProcessor) {
+      return NULL;
+    }
+
+    $html = $this->get_contents($src_url);
+    if (FALSE === $html) {
+      return NULL;
+    }
+
+    $preprocess_html_host_method = 'preprocess_html_' . str_replace(".", "_", $host);
+    if (method_exists($this, $preprocess_html_host_method)) {
+      $html = call_user_func_array(array($this, $preprocess_html_host_method), array($html));
+    }
+
+    $xmlDoc = $this->html_to_xml($html, $host);
+    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);


@@ -138,12 +283,18 @@ class Tweeper {
   }
 }
 
   }
 }
 

+function is_cli()
+{
+  return (php_sapi_name() === "cli");
+}
+

 function usage($argv)
 {
 function usage($argv)
 {

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

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

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

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


@@ -168,7 +319,8 @@ function parse_options_cli($argv, $argc)
       echo usage($argv);
       exit(0);
     default:
       echo usage($argv);
       exit(0);
     default:

-      die(usage($argv));
+      fwrite(STDERR, usage($argv));
+      exit(1);

     }
   }
 
     }
   }
 


@@ -193,21 +345,18 @@ function parse_options_query_string()
 }
 
 
 }
 
 

-if (php_sapi_name() != 'cli')
-  $options = parse_options_query_string();
-else
+if (is_cli()) {

   $options = parse_options_cli($argv, $argc);
   $options = parse_options_cli($argv, $argc);

+  $ERROR_STREAM = fopen('php://stderr', 'w');
+} else {
+  $options = parse_options_query_string();
+  $ERROR_STREAM = fopen('php://output', 'w');
+}

 
 

-if (!isset($options['src_url']))
-  die(usage($argv));
-
-$url = parse_url($options['src_url']);
-if (FALSE === $url || empty($url["host"]))
-  die("Invalid url: ${options['src_url']}\n");
-
-$stylesheet = __DIR__ . "/rss_converter_" . $url["host"] . ".xsl";
-if (FALSE === file_exists($stylesheet))
-  die("Conversion to RSS not supported: {$url["host"]}\n");
+if (!isset($options['src_url'])) {
+  fwrite($ERROR_STREAM, usage(is_cli() ? $argv : NULL));
+  exit(1);
+}

 
 

-$tweeper = new Tweeper($stylesheet, $options['generate_enclosure']);
+$tweeper = new Tweeper($options['generate_enclosure']);

 echo $tweeper->tweep($options['src_url']);
 echo $tweeper->tweep($options['src_url']);