Jamie Pratt
179 lines
6.9 KiB
PHP
179 lines
6.9 KiB
PHP
<?php // $Id$
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/**
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* Enable cookieless sessions by including $CFG->usesid=true;
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* in config.php.
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* Based on code from php manual by Richard at postamble.co.uk
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* Attempts to use cookies if cookies not present then uses session ids attached to all urls and forms to pass session id from page to page.
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* If site is open to google, google is given guest access as usual and there are no sessions. No session ids will be attached to urls for googlebot.
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* This doesn't require trans_sid to be turned on but this is recommended for better performance
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* you should put :
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* session.use_trans_sid = 1
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* in your php.ini file and make sure that you don't have a line like this in your php.ini
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* session.use_only_cookies = 1
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* @author Richard at postamble.co.uk and Jamie Pratt
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* @license http://www.gnu.org/copyleft/gpl.html GNU Public License
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*/
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class cookieless_sid {
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/**
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* @var string Using this variable to store $CFG->wwwroot. Found that in some versions of php the $CFG global was null in
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* the callback functions used by the output buffer.
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*/
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var $httproot = null;
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/**
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* @var string Using this variable to store $CFG->httpswwwroot.
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*/
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var $httpsroot = null;
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/**
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* @var boolean Using this variable to store $CFG->usesid.
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*/
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var $usesid = false;
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/**
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* You won't call this function directly. This function is used to process
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* text buffered by php in an output buffer. All output is run through this function
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* before it is ouput.
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* @param string $buffer is the output sent from php
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* @return string the output sent to the browser
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*/
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function ob_rewrite($buffer){
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$replacements = array(
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'/(<\s*(a|link|script|frame|area)\s[^>]*(href|src)\s*=\s*")([^"]*)(")/i',
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'/(<\s*(a|link|script|frame|area)\s[^>]*(href|src)\s*=\s*\')([^\']*)(\')/i');
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$buffer = preg_replace_callback($replacements, array($this, "rewrite_link_tag"), $buffer);
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$buffer = preg_replace('/<form\s[^>]*>/i',
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'\0<input type="hidden" name="' . session_name() . '" value="' . session_id() . '"/>', $buffer);
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return $buffer;
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}
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/**
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* You won't call this function directly. This function is used to process
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* text buffered by php in an output buffer. All output is run through this function
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* before it is ouput.
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* This function only processes absolute urls, it is used when we decide that
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* php is processing other urls itself but needs some help with internal absolute urls still.
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* @param string $buffer is the output sent from php
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* @return string the output sent to the browser
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*/
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function ob_rewrite_absolute($buffer){
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$replacements = array(
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'/(<\s*(a|link|script|frame|area)\s[^>]*(href|src)\s*=\s*")((?:http|https)[^"]*)(")/i',
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'/(<\s*(a|link|script|frame|area)\s[^>]*(href|src)\s*=\s*\')((?:http|https)[^\']*)(\')/i');
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$buffer = preg_replace_callback($replacements, array($this, "rewrite_link_tag"), $buffer);
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$buffer = preg_replace('/<form\s[^>]*>/i',
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'\0<input type="hidden" name="' . session_name() . '" value="' . session_id() . '"/>', $buffer);
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return $buffer;
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}
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/**
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* A function to process link, a and script tags found
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* by preg_replace_callback in ob_rewrite($buffer).
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*/
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function rewrite_link_tag($matches){
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$url = $matches[4];
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$url= $this->process_url($url);
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return $matches[1]. $url.$matches[5];
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}
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/**
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* You can call this function directly. This function is used to process
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* urls to add a moodle session id to the url for internal links.
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* @param string $url is a url
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* @return string the processed url
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*/
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function process_url($url) {
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if ((preg_match('/^(http|https):/i', $url)) // absolute url
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&& ((stripos($url, $this->httproot)!==0) && stripos($url, $this->httpsroot)!==0)) { // and not local one
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//error_log("non local url : $url ; \$CFG->wwwroot : ".$this->httproot);
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return $url; //don't attach sessid to non local urls
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}
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if ($url[0]=='#' || (stripos($url, 'javascript:')===0)) {
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//error_log("anchor : $url");
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return $url; //don't attach sessid to anchors
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}
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if (strpos($url, session_name())!==FALSE)
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{
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//error_log("already has one sessid : $url");
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return $url; //don't attach sessid to url that already has one sessid
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}
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if (strpos($url, "?")===FALSE){
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$append="?".strip_tags(session_name() . '=' . session_id() );
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} else {
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$append="&".strip_tags(session_name() . '=' . session_id() );
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}
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//put sessid before any anchor
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$p = strpos($url, "#");
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if($p!==FALSE){
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$anch = substr($url, $p);
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$url = substr($url, 0, $p).$append.$anch ;
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} else {
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$url .= $append ;
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}
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//error_log("added sid : $url");
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return $url;
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}
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/**
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* Call this function before there has been any output to the browser to
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* buffer output and add session ids to all internal links.
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*/
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function start_ob(){
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global $CFG;
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$this->httproot = $CFG->wwwroot;
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$this->httpsroot = $CFG->httpswwwroot;
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$this->usesid = !empty($CFG->usesid);
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//don't attach sess id for bots
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if (!empty($_SERVER['HTTP_USER_AGENT'])) {
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if (!empty($CFG->opentogoogle)) {
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if (strpos($_SERVER['HTTP_USER_AGENT'], 'Googlebot') !== false ) {
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@ini_set('session.use_trans_sid', '0'); // try and turn off trans_sid
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$CFG->usesid=false;
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return;
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}
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if (strpos($_SERVER['HTTP_USER_AGENT'], 'google.com') !== false ) {
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@ini_set('session.use_trans_sid', '0'); // try and turn off trans_sid
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$CFG->usesid=false;
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return;
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}
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}
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if (strpos($_SERVER['HTTP_USER_AGENT'], 'W3C_Validator') !== false ) {
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@ini_set('session.use_trans_sid', '0'); // try and turn off trans_sid
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$CFG->usesid=false;
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return;
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}
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}
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@ini_set('session.use_trans_sid', '1'); // try and turn on trans_sid
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if (ini_get('session.use_trans_sid')!=0 ){
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// use trans sid as its available
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ini_set('url_rewriter.tags', 'a=href,area=href,script=src,link=href,'
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. 'frame=src,form=fakeentry');
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ob_start(array($this, 'ob_rewrite_absolute'));
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}else{
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//rewrite all links ourselves
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ob_start(array($this, 'ob_rewrite'));
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}
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}
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}
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$url_processor_for_cookieless_sessions = new cookieless_sid();
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$url_processor_for_cookieless_sessions->start_ob();
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/**
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* You can call this function directly. This function is used to process
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* urls to add a moodle session id to the url for internal links.
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* Still using this function as a facade to access the instantiated object,
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* that actually does the processing, to preserve the old api.
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* @param string $url is a url
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* @return string the processed url
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*/
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function sid_process_url($url) {
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global $url_processor_for_cookieless_sessions;
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return $url_processor_for_cookieless_sessions->process_url($url);
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}
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?>
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