462 lines
15 KiB
PHP
462 lines
15 KiB
PHP
<?php
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/*
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* Project: MagpieRSS: a simple RSS integration tool
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* File: rss_fetch.inc, a simple functional interface
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to fetching and parsing RSS files, via the
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function fetch_rss()
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* Author: Kellan Elliott-McCrea <kellan@protest.net>
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* License: GPL
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*
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* The lastest version of MagpieRSS can be obtained from:
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* http://magpierss.sourceforge.net
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*
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* For questions, help, comments, discussion, etc., please join the
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* Magpie mailing list:
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* magpierss-general@lists.sourceforge.net
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*
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*/
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// Setup MAGPIE_DIR for use on hosts that don't include
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// the current path in include_path.
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// with thanks to rajiv and smarty
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if (!defined('DIR_SEP')) {
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define('DIR_SEP', DIRECTORY_SEPARATOR);
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}
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if (!defined('MAGPIE_DIR')) {
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define('MAGPIE_DIR', dirname(__FILE__) . DIR_SEP);
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}
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require_once( MAGPIE_DIR . 'rss_parse.inc' );
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require_once( MAGPIE_DIR . 'rss_cache.inc' );
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// for including 3rd party libraries
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define('MAGPIE_EXTLIB', MAGPIE_DIR . 'extlib' . DIR_SEP);
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require_once( MAGPIE_EXTLIB . 'Snoopy.class.inc');
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/*
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* CONSTANTS - redefine these in your script to change the
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* behaviour of fetch_rss() currently, most options effect the cache
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*
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* MAGPIE_CACHE_ON - Should Magpie cache parsed RSS objects?
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* For me a built in cache was essential to creating a "PHP-like"
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* feel to Magpie, see rss_cache.inc for rationale
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*
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*
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* MAGPIE_CACHE_DIR - Where should Magpie cache parsed RSS objects?
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* This should be a location that the webserver can write to. If this
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* directory does not already exist Mapie will try to be smart and create
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* it. This will often fail for permissions reasons.
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*
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*
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* MAGPIE_CACHE_AGE - How long to store cached RSS objects? In seconds.
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*
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*
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* MAGPIE_CACHE_FRESH_ONLY - If remote fetch fails, throw error
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* instead of returning stale object?
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*
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* MAGPIE_DEBUG - Display debugging notices?
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*
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*/
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/*=======================================================================*\
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Function: fetch_rss:
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Purpose: return RSS object for the give url
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maintain the cache
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Input: url of RSS file
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Output: parsed RSS object (see rss_parse.inc)
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NOTES ON CACHEING:
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If caching is on (MAGPIE_CACHE_ON) fetch_rss will first check the cache.
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NOTES ON RETRIEVING REMOTE FILES:
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If conditional gets are on (MAGPIE_CONDITIONAL_GET_ON) fetch_rss will
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return a cached object, and touch the cache object upon recieving a
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304.
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NOTES ON FAILED REQUESTS:
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If there is an HTTP error while fetching an RSS object, the cached
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version will be return, if it exists (and if MAGPIE_CACHE_FRESH_ONLY is off)
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\*=======================================================================*/
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define('MAGPIE_VERSION', '0.72');
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$MAGPIE_ERROR = "";
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function fetch_rss ($url) {
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// initialize constants
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init();
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if ( !isset($url) ) {
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error("fetch_rss called without a url");
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return false;
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}
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// if cache is disabled
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if ( !MAGPIE_CACHE_ON ) {
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// fetch file, and parse it
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$resp = _fetch_remote_file( $url );
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if ( is_success( $resp->status ) ) {
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return _response_to_rss( $resp );
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}
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else {
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error("Failed to fetch $url and cache is off");
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return false;
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}
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}
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// else cache is ON
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else {
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// Flow
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// 1. check cache
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// 2. if there is a hit, make sure its fresh
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// 3. if cached obj fails freshness check, fetch remote
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// 4. if remote fails, return stale object, or error
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$cache = new RSSCache( MAGPIE_CACHE_DIR, MAGPIE_CACHE_AGE );
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if (MAGPIE_DEBUG and $cache->ERROR) {
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debug($cache->ERROR, E_USER_WARNING);
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}
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$cache_status = 0; // response of check_cache
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$request_headers = array(); // HTTP headers to send with fetch
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$rss = 0; // parsed RSS object
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$errormsg = 0; // errors, if any
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// store parsed XML by desired output encoding
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// as character munging happens at parse time
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$cache_key = $url . MAGPIE_OUTPUT_ENCODING;
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if (!$cache->ERROR) {
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// return cache HIT, MISS, or STALE
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$cache_status = $cache->check_cache( $cache_key);
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}
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// if object cached, and cache is fresh, return cached obj
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if ( $cache_status == 'HIT' ) {
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$rss = $cache->get( $cache_key );
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if ( isset($rss) and $rss ) {
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// should be cache age
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$rss->from_cache = 1;
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if ( MAGPIE_DEBUG > 1) {
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debug("MagpieRSS: Cache HIT", E_USER_NOTICE);
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}
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return $rss;
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}
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}
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// else attempt a conditional get
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// setup headers
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if ( $cache_status == 'STALE' ) {
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$rss = $cache->get( $cache_key );
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if ( $rss and $rss->etag and $rss->last_modified ) {
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$request_headers['If-None-Match'] = $rss->etag;
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$request_headers['If-Last-Modified'] = $rss->last_modified;
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}
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}
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$resp = _fetch_remote_file( $url, $request_headers );
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if (isset($resp) and $resp) {
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if ($resp->status == '304' ) {
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// we have the most current copy
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if ( MAGPIE_DEBUG > 1) {
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debug("Got 304 for $url");
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}
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// reset cache on 304 (at minutillo insistent prodding)
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$cache->set($cache_key, $rss);
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return $rss;
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}
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elseif ( is_success( $resp->status ) ) {
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$rss = _response_to_rss( $resp );
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if ( $rss ) {
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if (MAGPIE_DEBUG > 1) {
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debug("Fetch successful");
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}
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// add object to cache
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$cache->set( $cache_key, $rss );
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return $rss;
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}
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}
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else {
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$errormsg = "Failed to fetch $url ";
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if ( $resp->status == '-100' ) {
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$errormsg .= "(Request timed out after " . MAGPIE_FETCH_TIME_OUT . " seconds)";
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}
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elseif ( $resp->error ) {
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# compensate for Snoopy's annoying habbit to tacking
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# on '\n'
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$http_error = substr($resp->error, 0, -2);
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$errormsg .= "(HTTP Error: $http_error)";
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}
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else {
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$errormsg .= "(HTTP Response: " . $resp->response_code .')';
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}
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}
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}
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else {
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$errormsg = "Unable to retrieve RSS file for unknown reasons.";
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}
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// else fetch failed
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// attempt to return cached object
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if ($rss) {
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if ( MAGPIE_DEBUG ) {
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debug("Returning STALE object for $url");
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}
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return $rss;
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}
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// else we totally failed
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error( $errormsg );
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return false;
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} // end if ( !MAGPIE_CACHE_ON ) {
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} // end fetch_rss()
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/*=======================================================================*\
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Function: error
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Purpose: set MAGPIE_ERROR, and trigger error
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\*=======================================================================*/
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function error ($errormsg, $lvl=E_USER_WARNING) {
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global $MAGPIE_ERROR;
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// append PHP's error message if track_errors enabled
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if ( isset($php_errormsg) ) {
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$errormsg .= " ($php_errormsg)";
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}
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if ( $errormsg ) {
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$errormsg = "MagpieRSS: $errormsg";
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$MAGPIE_ERROR = $errormsg;
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trigger_error( $errormsg, $lvl);
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}
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}
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function debug ($debugmsg, $lvl=E_USER_NOTICE) {
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trigger_error("MagpieRSS [debug] $debugmsg", $lvl);
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}
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/*=======================================================================*\
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Function: magpie_error
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Purpose: accessor for the magpie error variable
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\*=======================================================================*/
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function magpie_error ($errormsg="") {
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global $MAGPIE_ERROR;
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if ( isset($errormsg) and $errormsg ) {
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$MAGPIE_ERROR = $errormsg;
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}
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return $MAGPIE_ERROR;
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}
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/*=======================================================================*\
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Function: _fetch_remote_file
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Purpose: retrieve an arbitrary remote file
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Input: url of the remote file
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headers to send along with the request (optional)
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Output: an HTTP response object (see Snoopy.class.inc)
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\*=======================================================================*/
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function _fetch_remote_file ($url, $headers = "" ) {
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// Snoopy is an HTTP client in PHP
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$client = new Snoopy();
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$client->agent = MAGPIE_USER_AGENT;
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$client->read_timeout = MAGPIE_FETCH_TIME_OUT;
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$client->use_gzip = MAGPIE_USE_GZIP;
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if (is_array($headers) ) {
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$client->rawheaders = $headers;
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}
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@$client->fetch($url);
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return $client;
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}
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/*=======================================================================*\
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Function: _response_to_rss
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Purpose: parse an HTTP response object into an RSS object
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Input: an HTTP response object (see Snoopy)
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Output: parsed RSS object (see rss_parse)
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\*=======================================================================*/
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function _response_to_rss ($resp) {
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$rss = new MagpieRSS( $resp->results, MAGPIE_OUTPUT_ENCODING, MAGPIE_INPUT_ENCODING, MAGPIE_DETECT_ENCODING );
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// if RSS parsed successfully
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if ( $rss and !$rss->ERROR) {
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// find Etag, and Last-Modified
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foreach($resp->headers as $h) {
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// 2003-03-02 - Nicola Asuni (www.tecnick.com) - fixed bug "Undefined offset: 1"
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if (strpos($h, ": ")) {
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list($field, $val) = explode(": ", $h, 2);
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}
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else {
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$field = $h;
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$val = "";
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}
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if ( $field == 'ETag' ) {
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$rss->etag = $val;
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}
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if ( $field == 'Last-Modified' ) {
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$rss->last_modified = $val;
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}
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}
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return $rss;
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} // else construct error message
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else {
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$errormsg = "Failed to parse RSS file.";
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if ($rss) {
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$errormsg .= " (" . $rss->ERROR . ")";
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}
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error($errormsg);
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return false;
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} // end if ($rss and !$rss->error)
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}
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/*=======================================================================*\
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Function: init
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Purpose: setup constants with default values
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check for user overrides
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\*=======================================================================*/
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function init () {
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if ( defined('MAGPIE_INITALIZED') ) {
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return;
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}
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else {
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define('MAGPIE_INITALIZED', true);
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}
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if ( !defined('MAGPIE_CACHE_ON') ) {
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define('MAGPIE_CACHE_ON', true);
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}
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if ( !defined('MAGPIE_CACHE_DIR') ) {
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define('MAGPIE_CACHE_DIR', './cache');
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}
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if ( !defined('MAGPIE_CACHE_AGE') ) {
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define('MAGPIE_CACHE_AGE', 60*60); // one hour
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}
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if ( !defined('MAGPIE_CACHE_FRESH_ONLY') ) {
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define('MAGPIE_CACHE_FRESH_ONLY', false);
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}
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if ( !defined('MAGPIE_OUTPUT_ENCODING') ) {
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define('MAGPIE_OUTPUT_ENCODING', 'ISO-8859-1');
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}
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if ( !defined('MAGPIE_INPUT_ENCODING') ) {
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define('MAGPIE_INPUT_ENCODING', null);
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}
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if ( !defined('MAGPIE_DETECT_ENCODING') ) {
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define('MAGPIE_DETECT_ENCODING', true);
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}
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if ( !defined('MAGPIE_DEBUG') ) {
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define('MAGPIE_DEBUG', 0);
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}
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if ( !defined('MAGPIE_USER_AGENT') ) {
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$ua = 'MagpieRSS/'. MAGPIE_VERSION . ' (+http://magpierss.sf.net';
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if ( MAGPIE_CACHE_ON ) {
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$ua = $ua . ')';
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}
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else {
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$ua = $ua . '; No cache)';
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}
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if ( defined('MAGPIE_USER_AGENT_EXT') ) {
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$ua = $ua . MAGPIE_USER_AGENT_EXT;
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}
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define('MAGPIE_USER_AGENT', $ua);
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}
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if ( !defined('MAGPIE_FETCH_TIME_OUT') ) {
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define('MAGPIE_FETCH_TIME_OUT', 5); // 5 second timeout
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}
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// use gzip encoding to fetch rss files if supported?
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if ( !defined('MAGPIE_USE_GZIP') ) {
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define('MAGPIE_USE_GZIP', true);
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}
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}
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// NOTE: the following code should really be in Snoopy, or at least
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// somewhere other then rss_fetch!
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/*=======================================================================*\
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HTTP STATUS CODE PREDICATES
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These functions attempt to classify an HTTP status code
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based on RFC 2616 and RFC 2518.
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All of them take an HTTP status code as input, and return true or false
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All this code is adapted from LWP's HTTP::Status.
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\*=======================================================================*/
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/*=======================================================================*\
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Function: is_info
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Purpose: return true if Informational status code
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\*=======================================================================*/
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function is_info ($sc) {
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return $sc >= 100 && $sc < 200;
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}
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/*=======================================================================*\
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Function: is_success
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Purpose: return true if Successful status code
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\*=======================================================================*/
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function is_success ($sc) {
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return $sc >= 200 && $sc < 300;
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}
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/*=======================================================================*\
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Function: is_redirect
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Purpose: return true if Redirection status code
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\*=======================================================================*/
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function is_redirect ($sc) {
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return $sc >= 300 && $sc < 400;
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}
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/*=======================================================================*\
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Function: is_error
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Purpose: return true if Error status code
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\*=======================================================================*/
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function is_error ($sc) {
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return $sc >= 400 && $sc < 600;
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}
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/*=======================================================================*\
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Function: is_client_error
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Purpose: return true if Error status code, and its a client error
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\*=======================================================================*/
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function is_client_error ($sc) {
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return $sc >= 400 && $sc < 500;
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}
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/*=======================================================================*\
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Function: is_client_error
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Purpose: return true if Error status code, and its a server error
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\*=======================================================================*/
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function is_server_error ($sc) {
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return $sc >= 500 && $sc < 600;
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}
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?>
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