Hi,

This plugins in not compatible with farming techniques described in https://www.dokuwiki.org/farms#b_htaccess_based_setup . This technique adds an HTTP GET parametre.

When the doku text is parsed, a cachefilename is computed based on the md5 sum of the graph parametres, and the img URL that contains the parametres is created. When the browser later GETs the image, the farming rewriting rules add the animal=foo parametre to the URL parametre list. Graphviz plugin then computes the md5 out of the parametre list, which just happens to be different from the initial parametre list. Cache file has a different name, is not found; user gets the error image :-(.

This simple patch filters out any unexpected GET parameters in the _imgfile function, making the plugin compatible with the farming technique.

diff -Naur syntax.php.orig syntax.php 
--- syntax.php.orig 2013-04-03 05:41:13.111977071 +0200
+++ syntax.php  2013-04-03 06:08:48.652007895 +0200
@@ -119,6 +119,8 @@
      * Return path to the rendered image on our local system
      */
     function _imgfile($data){
+   // filter out unwanted GET parametres
+   $data=array_intersect_key( $data, array( 'width' => 1, 'height' => 1, 'layout' => 1, 'align' => 1, 'version' => 1, 'md5' => 1 ));
         $cache  = $this->_cachename($data,'png');

         // create the file if needed

/Schplurtz