Handlers and Filters

PAW differentiates between Handlers and Filters.

Handlers act on HTTP requests, while Filters act on the HTTP responses.

 Custom Filters

Custom Filters () are not part of the HTTP proxy filter chain!


Junkbuster Blocklist
(standard Handler in the Brazil package from SUN)
Filters unwanted websites. If such a site is found only a transparent GIF is returned, leaving the page empty.
Blocked sites can be configured in the file blockfile.
Request Headers Allows the modificatin of Request Headers (insert and delete).
Header configuration is stored in the file headers.


RegExp Filter
This filter is used to filter HTTP responses with regular expression.
Replace and size filters are supported.

onLoad Filter Filters onLoad JavasScript instructions in HTML pages to stop them from executing scripts on startup.

onUnLoad Filter Filters onUnLoad JavasScript instructions in HTML pages to stop them from executing scripts when leaving the page.

MS Smart Tag Filter Inserts a meta tag in HTML pages to disallow MS Smart Tags.

Appelet Filters Removes applets from Web Pages.

ActiveX Filter Removes ActiveX Controls (Object tags) from Web Pages.

Image Filter Removes images from Web Pages.

Pop-Up Filter Removes popups from Web Pages. But it is still possible to open windows after the Web page has been loaded.
This filter should be used together with the onLoad Filter to make sure that popups are not opened by using the unLoad instruction.

Enable Right-Click Menu Filter This filter enables right-mouse click on web pages where right-mouse click is disabled.

Banner size Filter This filter removes images with specific sizes from web pages. The sizes are specified in the file bannersizes.Note: If there are a log of sizes specified this filter may slowdown the serve. In this case it is recommended to disable this filter and to rely on theGIF Size Filter which also uses the file bannersizes.

WebBug Filter Filters images with specified sizes. This filter is used to filter fake images with very small sizes (mostly 1x1 pixels) which may trigger unwanted scripts on a remote server.

GIF Filter

Filters animated gif images in the way that it removed all but the first frame.
GIF Size Filter
Filters GIF images by size. It uses the file bannersizes for size information.
Virus Filter
This filter is highly experimental!
This filter allows to plug in a virus scanner. The drawback is, that the file has first to be completely downloaded by the PAW Server, before it can be delivered to the user.
Thew filter has been tested with f-prot beta for Linux.
For more details on the configuration see the file virus.conf