Question

As mentioned in BulletListNotRenderedOnOutputOfPlugin, I have a plugin that extracts form data and displays it. I now came across a bug in my plugin when rendering a preview page: Within the plugin, I use TWiki::Func::readTopic() to extract the meta data and read form fields from that. The problem is that when rendering the preview page, my plugin still uses the data stored on disk to render the field's value instead of the data entered on the edit page.

Is there a way to get the topic's data (text and meta) from within a plugin when previewing a topic?

Environment

-- ThomasJachmann - 02 Oct 2003

Answer

I hacked a solution myself now, unfortunately having to change TWiki core code:

• preview script

  $text = $meta->write( $text );  # add meta data for Plugin callback
  TWiki::Plugins::afterEditHandler( $text, $topic, $webName );
  $meta = TWiki::Meta->remove();  # remove all meta data
  $text = $meta->read( $text );   # restore meta data
       

  instead of just

  TWiki::Plugins::afterEditHandler( $text, $topic, $webName );
       

  This code is taken from TWiki::Store::saveTopic

• TWiki::Plugins::KnowledgeBasePlugin::afterEditHandler
  This method now takes the meta data from the $text variable and extracts the meta data which will be used in subsequent calls to the plugin during preview

BTW: Is there a reason why meta data is contained within $text for say beforeSaveHandler but not for afterEditHandler?

Maybe someone can approve/disapprove my approach.

-- ThomasJachmann - 10 Oct 2003

What you describe seems very convoluted. TWiki::Form::fieldVars2Meta( $webName, $query, $meta ) is available to convert query parameters to $meta; you should probably use this instead of touching the core code.

The various handler APIs are not well specced; the asymmetry in the calls is probably just due to the way the handler calls were added and the needs at the time of the person who added them. I suspect there is no "plan" behind the difference.

-- CrawfordCurrie - 02 Jun 2004