cache, metadata & purgefile updates

Cache
- add dependency for metadata renderer file
- check metadata for end of page life, "date valid end".

Metadata Renderer
- RSS syntax mode now sets rendered page expiry, "date valid end"
  and includes the feed URL in "relation haspart".

Purgefile
For all wiki installations the purgefile records the earliest
time before which no cache purge (based on data consistency)
is required. Cache files older than this time MAY need to be
purged.
- remove purgeonadd configuration setting

darcs-hash:20060924202157-9b6ab-4531e91411c41914eeab2b6a8160c3d46b001cee.gz

4 files changed, 36 insertions, 11 deletions

diff --git a/inc/cache.php b/inc/cache.php
index ae27f4e9e..767ad8a35 100644
--- a/inc/cache.php
+++ b/inc/cache.php
@@ -36,6 +36,7 @@ class cache {
    * @param  array   $depends   array of cache dependencies, support dependecies:
    *                            'age'   => max age of the cache in seconds
    *                            'files' => cache must be younger than mtime of each file
+   *                                       (nb. dependency passes if file doesn't exist)
    *
    * @return bool    true if cache can be used, false otherwise
    */
@@ -218,14 +219,21 @@ class cache_renderer extends cache_parser {
 
     if (!parent::_useCache()) return false;
 
-    // for wiki pages, check for internal link status changes
+    // for wiki pages, check metadata dependencies
     if (isset($this->page)) {
+      $metadata = p_get_metadata($this->page);
 
-      // check the purgefile
+      // page has an expiry time, after which it should be re-rendered (RSS feeds use this)
+      $page_expiry = $metadata['date']['valid']['end'];
+      if (!empty($page_expiry) && (time() > $page_expiry)) return false;
+
+      // check currnent link existence is consistent with cache version
+      // first check the purgefile
       // - if the cache is more recent that the purgefile we know no links can have been updated
       if ($this->_time < @filemtime($conf['cachedir'].'/purgefile')) {
 
-        $links = p_get_metadata($this->page,"relation references");
+#       $links = p_get_metadata($this->page,"relation references");
+        $links = $metadata['relation']['references'];
 
         if (!empty($links)) {
           foreach ($links as $id => $exists) {
@@ -242,9 +250,20 @@ class cache_renderer extends cache_parser {
 
     // renderer cache file dependencies ...
     $files = array(
-                   DOKU_INC.'inc/parser/'.$this->mode.'.php',            // ... the renderer
+                   DOKU_INC.'inc/parser/'.$this->mode.'.php',       // ... the renderer
              );
-    if (isset($this->page)) { $files[] = metaFN($this->page,'.meta'); }  // ... the page's own metadata
+
+    // page implies metadata and possibly some other dependencies
+    if (isset($this->page)) {
+      $metafile = metaFN($this->page,'.meta');
+      if (@file_exists($metafile)) {
+        $files[] = $metafile;                                       // ... the page's own metadata
+        $files[] = DOKU_INC.'inc/parser/metadata.php';              // ... the metadata renderer
+      } else {
+        $this->depends['purge'] = true;                             // ... purging cache will generate metadata
+				return;
+      }
+    }
 
     $this->depends['files'] = !empty($this->depends['files']) ? array_merge($files, $this->depends['files']) : $files;
     parent::_addDependencies();
diff --git a/inc/common.php b/inc/common.php
index 9a3cd6d8b..c2a6903ab 100644
--- a/inc/common.php
+++ b/inc/common.php
@@ -722,10 +722,8 @@ function saveWikiText($id,$text,$summary,$minor=false){
   notify($id,'admin',$old,$summary,$minor);
   notify($id,'subscribers',$old,$summary,$minor);
 
-  //purge cache on add by updating the purgefile
-  if($conf['purgeonadd'] && (!$old || $del)){
-    io_saveFile($conf['cachedir'].'/purgefile',time());
-  }
+  // update the purgefile (timestamp of the last time anything within the wiki was changed)
+  io_saveFile($conf['cachedir'].'/purgefile',time());
 }
 
 /**
diff --git a/inc/parser/metadata.php b/inc/parser/metadata.php
index fea2d48f2..9704c0475 100644
--- a/inc/parser/metadata.php
+++ b/inc/parser/metadata.php
@@ -325,7 +325,15 @@ class Doku_Renderer_metadata extends Doku_Renderer {
     if ($this->capture && $title) $this->doc .= '['.$title.']';
   }
 
-  function rss($url){}
+  function rss($url,$params) {
+    global $conf;
+
+    $this->meta['relation']['haspart'][$url] = true;
+    $this->meta['date']['valid']['end'] =
+         empty($this->meta['date']['valid']['end']) ?
+             time() + $conf['rss_update'] :
+             min($this->meta['date']['valid']['end'], time() + $conf['rss_update']);
+  }
 
   function table_open($maxcols = NULL, $numrows = NULL){}
   function table_close(){}
diff --git a/inc/parser/xhtml.php b/inc/parser/xhtml.php
index c805dae70..c56367f47 100644
--- a/inc/parser/xhtml.php
+++ b/inc/parser/xhtml.php
@@ -502,7 +502,7 @@ class Doku_Renderer_xhtml extends Doku_Renderer {
         }
 
         //keep hash anchor
-        list($id,$hash) = split('#',$id,2);
+        list($id,$hash) = explode('#',$id,2);
 
         //prepare for formating
         $link['target'] = $conf['target']['wiki'];