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Diffstat (limited to 'inc/magpie/rss_fetch.inc')
| -rw-r--r-- | inc/magpie/rss_fetch.inc | 438 |
1 files changed, 438 insertions, 0 deletions
diff --git a/inc/magpie/rss_fetch.inc b/inc/magpie/rss_fetch.inc new file mode 100644 index 000000000..5c559baef --- /dev/null +++ b/inc/magpie/rss_fetch.inc @@ -0,0 +1,438 @@ +<?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', '0.61'); + +$MAGPIE_ERROR = ""; + +function fetch_rss ($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 + $errormsg = 0; // errors, if any + + if (!$cache->ERROR) { + // return cache HIT, MISS, or STALE + $cache_status = $cache->check_cache( $url ); + } + + // if object cached, and cache is fresh, return cached obj + if ( $cache_status == 'HIT' ) { + $rss = $cache->get( $url ); + if ( isset($rss) and $rss ) { + $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( $url ); + if ( $rss->etag and $rss->last_modified ) { + $request_headers['If-None-Match'] = $rss->etag; + $request_headers['If-Last-Modified'] = $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) + $cache->set($url, $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( $url, $rss ); + return $rss; + } + } + else { + $errormsg = "Failed to fetch $url. "; + if ( $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 ); + + // 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 == 'Last-Modified' ) { + $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', 1); + } + + if ( !defined('MAGPIE_CACHE_ON') ) { + define('MAGPIE_CACHE_ON', 1); + } + + 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', 0); + } + + 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', $ua); + } + + if ( !defined('MAGPIE_FETCH_TIME_OUT') ) { + define('MAGPIE_FETCH_TIME_OUT', 5); // 5 second timeout + } + + // use gzip encoding to fetch rss files if supported? + if ( !defined('MAGPIE_USE_GZIP') ) { + define('MAGPIE_USE_GZIP', true); + } +} + +// NOTE: the following code should really be in Snoopy, or at least +// somewhere other then rss_fetch! + +/*=======================================================================*\ + HTTP STATUS CODE PREDICATES + These functions attempt to classify an HTTP status code + based on RFC 2616 and RFC 2518. + + All of them take an HTTP status code as input, and return true or false + + All this code is adapted from LWP's HTTP::Status. +\*=======================================================================*/ + + +/*=======================================================================*\ + Function: is_info + Purpose: return true if Informational status code +\*=======================================================================*/ +function is_info ($sc) { + return $sc >= 100 && $sc < 200; +} + +/*=======================================================================*\ + Function: is_success + Purpose: return true if Successful status code +\*=======================================================================*/ +function is_success ($sc) { + return $sc >= 200 && $sc < 300; +} + +/*=======================================================================*\ + Function: is_redirect + Purpose: return true if Redirection status code +\*=======================================================================*/ +function is_redirect ($sc) { + return $sc >= 300 && $sc < 400; +} + +/*=======================================================================*\ + Function: is_error + Purpose: return true if Error status code +\*=======================================================================*/ +function is_error ($sc) { + return $sc >= 400 && $sc < 600; +} + +/*=======================================================================*\ + Function: is_client_error + Purpose: return true if Error status code, and its a client error +\*=======================================================================*/ +function is_client_error ($sc) { + return $sc >= 400 && $sc < 500; +} + +/*=======================================================================*\ + Function: is_client_error + Purpose: return true if Error status code, and its a server error +\*=======================================================================*/ +function is_server_error ($sc) { + return $sc >= 500 && $sc < 600; +} + +?> |