<?php
  /*
   * Project:     MagpieRSS: a simple RSS integration tool
   * File:        rss_fetch.inc, a simple functional interface
                  to fetching and parsing RSS files, via the
                  function fetch_rss()
   * Author:      Kellan Elliott-McCrea <kellan@protest.net>
   * License:     GPL
   *
   * The lastest version of MagpieRSS can be obtained from:
   * http://magpierss.sourceforge.net
   *
   * For questions, help, comments, discussion, etc., please join the
   * Magpie mailing list:
   * magpierss-general@lists.sourceforge.net
   *
   */
   
  // Setup MAGPIE_DIR for use on hosts that don't include
  // the current path in include_path.
  // with thanks to rajiv and smarty
  if (!defined('DIR_SEP')) {
      define('DIR_SEP', DIRECTORY_SEPARATOR);
  }
  
  if (!defined('MAGPIE_DIR')) {
      define('MAGPIE_DIR', dirname(__FILE__) . DIR_SEP);
  }
  
  require_once( MAGPIE_DIR . 'rss_parse.inc' );
  require_once( MAGPIE_DIR . 'rss_cache.inc' );
  
  // for including 3rd party libraries
  define('MAGPIE_EXTLIB', MAGPIE_DIR . 'extlib' . DIR_SEP);
  require_once( MAGPIE_EXTLIB . 'Snoopy.class.inc');
  
  /* 
   * CONSTANTS - redefine these in your script to change the
   * behaviour of fetch_rss() currently, most options effect the cache
   *
   * MAGPIE_CACHE_ON - Should Magpie cache parsed RSS objects? 
   * For me a built in cache was essential to creating a "PHP-like" 
   * feel to Magpie, see rss_cache.inc for rationale
   *
   *
   * MAGPIE_CACHE_DIR - Where should Magpie cache parsed RSS objects?
   * This should be a location that the webserver can write to.   If this 
   * directory does not already exist Mapie will try to be smart and create 
   * it.  This will often fail for permissions reasons.
   *
   *
   * MAGPIE_CACHE_AGE - How long to store cached RSS objects? In seconds.
   *
   *
   * MAGPIE_CACHE_FRESH_ONLY - If remote fetch fails, throw error
   * instead of returning stale object?
   *
   * MAGPIE_DEBUG - Display debugging notices?
   *
  */
  
  /*=======================================================================*\
      Function: fetch_rss: 
      Purpose:  return RSS object for the give url
                maintain the cache
      Input:    url of RSS file
      Output:   parsed RSS object (see rss_parse.inc)
  
      NOTES ON CACHEING:  
      If caching is on (MAGPIE_CACHE_ON) fetch_rss will first check the cache.
      
      NOTES ON RETRIEVING REMOTE FILES:
      If conditional gets are on (MAGPIE_CONDITIONAL_GET_ON) fetch_rss will
      return a cached object, and touch the cache object upon recieving a
      304.
      
      NOTES ON FAILED REQUESTS:
      If there is an HTTP error while fetching an RSS object, the cached
      version will be return, if it exists (and if MAGPIE_CACHE_FRESH_ONLY is off)
  \*=======================================================================*/
  
  define('MAGPIE_VERSION', '0.72');
  
  $MAGPIE\_ERROR\; =\; "";\; function\; fetch\_rss\; ($url) {
      // initialize constants
      init();
      
      if ( !isset($url)\; )\; \{\; error("fetch\_rss\; called\; without\; a\; url");\; return\; false;\; \}\; //\; if\; cache\; is\; disabled\; if\; (\; !MAGPIE\_CACHE\_ON\; )\; \{\; //\; fetch\; file,\; and\; parse\; it$resp = _fetch_remote_file( $url\; );\; if\; (\; is\_success($resp->status ) ) {
              return _response_to_rss( $resp\; );\; \}\; else\; \{\; error("Failed\; to\; fetch$url and cache is off");
              return false;
          }
      } 
      // else cache is ON
      else {
          // Flow
          // 1. check cache
          // 2. if there is a hit, make sure its fresh
          // 3. if cached obj fails freshness check, fetch remote
          // 4. if remote fails, return stale object, or error
          
          $cache\; =\; new\; RSSCache(\; MAGPIE\_CACHE\_DIR,\; MAGPIE\_CACHE\_AGE\; );\; if\; (MAGPIE\_DEBUG\; and$cache->ERROR) {
              debug($cache->ERROR,\; E\_USER\_WARNING);\; \}$cache_status    = 0;       // response of check_cache
          $request\_headers\; =\; array();\; //\; HTTP\; headers\; to\; send\; with\; fetch$rss             = 0;       // parsed RSS object
          $errormsg\; =\; 0;\; //\; errors,\; if\; any\; //\; store\; parsed\; XML\; by\; desired\; output\; encoding\; //\; as\; character\; munging\; happens\; at\; parse\; time$cache_key       = $url\; .\; MAGPIE\_OUTPUT\_ENCODING;\; if\; (!$cache->ERROR) {
              // return cache HIT, MISS, or STALE
              $cache\_status\; =$cache->check_cache( $cache\_key);\; \}\; //\; if\; object\; cached,\; and\; cache\; is\; fresh,\; return\; cached\; obj\; if\; ($cache_status == 'HIT' ) {
              $rss\; =$cache->get( $cache\_key\; );\; if\; (\; isset($rss) and $rss\; )\; \{\; //\; should\; be\; cache\; age$rss->from_cache = 1;
                  if ( MAGPIE_DEBUG > 1) {
                      debug("MagpieRSS: Cache HIT", E_USER_NOTICE);
                  }
                  return $rss;\; \}\; \}\; //\; else\; attempt\; a\; conditional\; get\; //\; setup\; headers\; if\; ($cache_status == 'STALE' ) {
              $rss\; =$cache->get( $cache\_key\; );\; if\; ($rss and $rss->etag\; and$rss->last_modified ) {
                  $request\_headers[\text{'}If-None-Match\text{'}]\; =$rss->etag;
                  $request\_headers[\text{'}If-Last-Modified\text{'}]\; =$rss->last_modified;
              }
          }
          
          $resp\; =\; \_fetch\_remote\_file($url, $request\_headers\; );\; if\; (isset($resp) and $resp)\; \{\; if\; ($resp->status == '304' ) {
                  // we have the most current copy
                  if ( MAGPIE_DEBUG > 1) {
                      debug("Got 304 for $url");\; \}\; //\; reset\; cache\; on\; 304\; (at\; minutillo\; insistent\; prodding)$cache->set($cache\_key,$rss);
                  return $rss;\; \}\; elseif\; (\; is\_success($resp->status ) ) {
                  $rss\; =\; \_response\_to\_rss($resp );
                  if ( $rss\; )\; \{\; if\; (MAGPIE\_DEBUG\; >\; 1)\; \{\; debug("Fetch\; successful");\; \}\; //\; add\; object\; to\; cache$cache->set( $cache\_key,$rss );
                      return $rss;\; \}\; \}\; else\; \{$errormsg = "Failed to fetch $url\; ";\; if\; ($resp->status == '-100' ) {
                      $errormsg\; .=\; "(Request\; timed\; out\; after\; "\; .\; MAGPIE\_FETCH\_TIME\_OUT\; .\; "\; seconds)";\; \}\; elseif\; ($resp->error ) {
                      # compensate for Snoopy's annoying habbit to tacking
                      # on '\n'
                      $http\_error\; =\; substr($resp->error, 0, -2); 
                      $errormsg\; .=\; "(HTTP\; Error:$http_error)";
                  }
                  else {
                      $errormsg\; .=\; "(HTTP\; Response:\; "\; .$resp->response_code .')';
                  }
              }
          }
          else {
              $errormsg\; =\; "Unable\; to\; retrieve\; RSS\; file\; for\; unknown\; reasons.";\; \}\; //\; else\; fetch\; failed\; //\; attempt\; to\; return\; cached\; object\; if\; ($rss) {
              if ( MAGPIE_DEBUG ) {
                  debug("Returning STALE object for $url");\; \}\; return$rss;
          }
          
          // else we totally failed
          error( $errormsg\; );\; return\; false;\; \}\; //\; end\; if\; (\; !MAGPIE\_CACHE\_ON\; )\; \{\; \}\; //\; end\; fetch\_rss()$/*=======================================================================*\
      Function:   error
      Purpose:    set MAGPIE_ERROR, and trigger error
  \*=======================================================================*/
  
  function error (errormsg, $lvl=E\_USER\_WARNING)\; \{\; global$MAGPIE_ERROR;
          
          // append PHP's error message if track_errors enabled
          if ( isset($php\_errormsg)\; )\; \{$errormsg .= " ($php\_errormsg)";\; \}\; if\; ($errormsg ) {
              $errormsg\; =\; "MagpieRSS:$errormsg";
              $MAGPIE\_ERROR\; =$errormsg;
              trigger_error( $errormsg,$lvl);                
          }
  }
  
  function debug ($debugmsg,$lvl=E_USER_NOTICE) {
      trigger_error("MagpieRSS [debug] $debugmsg",$lvl);
  }
              
  /*=======================================================================*\
      Function:   magpie_error
      Purpose:    accessor for the magpie error variable
  \*=======================================================================*/
  function magpie_error ($errormsg="")\; \{\; global$MAGPIE_ERROR;
      
      if ( isset($errormsg)\; and$errormsg ) { 
          $MAGPIE\_ERROR\; =$errormsg;
      }
      
      return $MAGPIE\_ERROR;\; \}$/*=======================================================================*\
      Function:   _fetch_remote_file
      Purpose:    retrieve an arbitrary remote file
      Input:      url of the remote file
                  headers to send along with the request (optional)
      Output:     an HTTP response object (see Snoopy.class.inc)  
  \*=======================================================================*/
  function _fetch_remote_file (url, $headers\; =\; ""\; )\; \{$// Snoopy is an HTTP client in PHP
      client = new Snoopy();
      $client->agent\; =\; MAGPIE\_USER\_AGENT;$client->read_timeout = MAGPIE_FETCH_TIME_OUT;
      $client->use\_gzip\; =\; MAGPIE\_USE\_GZIP;\; if\; (is\_array($headers) ) {
          $client->rawheaders\; =$headers;
      }
      
      @$client->fetch($url);
      return $client;\; \}$/*=======================================================================*\
      Function:   _response_to_rss
      Purpose:    parse an HTTP response object into an RSS object
      Input:      an HTTP response object (see Snoopy)
      Output:     parsed RSS object (see rss_parse)
  \*=======================================================================*/
  function _response_to_rss (resp) {
      $rss\; =\; new\; MagpieRSS($resp->results, MAGPIE_OUTPUT_ENCODING, MAGPIE_INPUT_ENCODING, MAGPIE_DETECT_ENCODING );
      
      // if RSS parsed successfully       
      if ( $rss\; and\; !$rss->ERROR) {
          
          // find Etag, and Last-Modified
          foreach($resp->headers\; as$h) {
              // 2003-03-02 - Nicola Asuni (www.tecnick.com) - fixed bug "Undefined offset: 1"
              if (strpos($h,\; ":\; "))\; \{\; list($field, $val)\; =\; explode(":\; ",$h, 2);
              }
              else {
                  $field\; =$h;
                  $val\; =\; "";\; \}\; if\; ($field == 'ETag' ) {
                  $rss->etag\; =$val;
              }
              
              if ( $field\; ==\; \text{'}Last-Modified\text{'}\; )\; \{$rss->last_modified = $val;\; \}\; \}\; return$rss;    
      } // else construct error message
      else {
          $errormsg\; =\; "Failed\; to\; parse\; RSS\; file.";\; if\; ($rss) {
              $errormsg\; .=\; "\; ("\; .$rss->ERROR . ")";
          }
          error($errormsg);\; return\; false;\; \}\; //\; end\; if\; ($rss and !$rss->error)\; \}$/*=======================================================================*\
      Function:   init
      Purpose:    setup constants with default values
                  check for user overrides
  \*=======================================================================*/
  function init () {
      if ( defined('MAGPIE_INITALIZED') ) {
          return;
      }
      else {
          define('MAGPIE_INITALIZED', true);
      }
      
      if ( !defined('MAGPIE_CACHE_ON') ) {
          define('MAGPIE_CACHE_ON', true);
      }
  
      if ( !defined('MAGPIE_CACHE_DIR') ) {
          define('MAGPIE_CACHE_DIR', './cache');
      }
  
      if ( !defined('MAGPIE_CACHE_AGE') ) {
          define('MAGPIE_CACHE_AGE', 60*60); // one hour
      }
  
      if ( !defined('MAGPIE_CACHE_FRESH_ONLY') ) {
          define('MAGPIE_CACHE_FRESH_ONLY', false);
      }
  
      if ( !defined('MAGPIE_OUTPUT_ENCODING') ) {
          define('MAGPIE_OUTPUT_ENCODING', 'ISO-8859-1');
      }
      
      if ( !defined('MAGPIE_INPUT_ENCODING') ) {
          define('MAGPIE_INPUT_ENCODING', null);
      }
      
      if ( !defined('MAGPIE_DETECT_ENCODING') ) {
          define('MAGPIE_DETECT_ENCODING', true);
      }
      
      if ( !defined('MAGPIE_DEBUG') ) {
          define('MAGPIE_DEBUG', 0);
      }
      
      if ( !defined('MAGPIE_USER_AGENT') ) {
          ua = 'MagpieRSS/'. MAGPIE_VERSION . ' (+http://magpierss.sf.net';
          
          if ( MAGPIE_CACHE_ON ) {
              $ua\; =$ua . ')';
          }
          else {
              $ua\; =$ua . '; No cache)';
          }
          
          define('MAGPIE_USER_AGENT', $ua);\; \}\; if\; (\; !defined(\text{'}MAGPIE\_FETCH\_TIME\_OUT\text{'})\; )\; \{\; define(\text{'}MAGPIE\_FETCH\_TIME\_OUT\text{'},\; 5);\; //\; 5\; second\; timeout\; \}\; //\; use\; gzip\; encoding\; to\; fetch\; rss\; files\; if\; supported?\; if\; (\; !defined(\text{'}MAGPIE\_USE\_GZIP\text{'})\; )\; \{\; define(\text{'}MAGPIE\_USE\_GZIP\text{'},\; true);\; \}\; \}\; //\; NOTE:\; the\; following\; code\; should\; really\; be\; in\; Snoopy,\; or\; at\; least\; //\; somewhere\; other\; then\; rss\_fetch!$/*=======================================================================*\
      HTTP STATUS CODE PREDICATES
      These functions attempt to classify an HTTP status code
      based on RFC 2616 and RFC 2518.
      
      All of them take an HTTP status code as input, and return true or false
  
      All this code is adapted from LWP's HTTP::Status.
  \*=======================================================================*/
  
  /*=======================================================================*\
      Function:   is_info
      Purpose:    return true if Informational status code
  \*=======================================================================*/
  function is_info (sc) { 
      return sc < 200; 
  }
  
  /*=======================================================================*\
      Function:   is_success
      Purpose:    return true if Successful status code
  \*=======================================================================*/
  function is_success ($sc)\; \{\; return$sc >= 200 && /*=======================================================================*\
      Function:   is_redirect
      Purpose:    return true if Redirection status code
  \*=======================================================================*/
  function is_redirect (sc) { 
      return sc < 400; 
  }
  
  /*=======================================================================*\
      Function:   is_error
      Purpose:    return true if Error status code
  \*=======================================================================*/
  function is_error ($sc)\; \{\; return$sc >= 400 && /*=======================================================================*\
      Function:   is_client_error
      Purpose:    return true if Error status code, and its a client error
  \*=======================================================================*/
  function is_client_error (sc) { 
      return sc < 500; 
  }
  
  /*=======================================================================*\
      Function:   is_client_error
      Purpose:    return true if Error status code, and its a server error
  \*=======================================================================*/
  function is_server_error ($sc)\; \{\; return$sc >= 500 &&