goofyproxy

goofyproxy acts as an HTTP proxy that filters received data through an external process.
To use it, run it and go in network preferences of your browser to configure localhost:PORT as proxy for HTTP connections.

Build

• Get the Qt Library version 4.5.0 or higher
• Run: qmake && make

Usage and examples

goofyproxy PORT CONTENTTYPEPREFIX COMMAND [COMMANDARGS]

Open an HTTP proxy on port PORT. Each response with a Content-Type that starts with CONTENTTYPEPREFIX gets its payload sent through COMMAND's stdin. Stdout is sent back to the client.

Using sed

goofyproxy 8080 text/html sed '{s/<p\([> ]\)/<h1\1/; s/<\/p>/<\/h1>/}'
would change every occurence of <p></p> for <h1></h1> in HTML resources.

Using ImageMagick

goofyproxy 8080 image/ convert - -colorspace Gray -sketch 0x20+120 -

goofyproxy 8080 image/ convert - -paint 3 -

Using perl

goofyproxy 8080 text/html perl -nle ' $_=~ s/(?!<.*?)([^\w])cat(?![^<>]*?>)/\1Batman/ig; print $_'

Tested platforms

Linux, Mac OS X

A serious issue is often seen on Windows machines, at least on mine, where the client connection would be closed automatically when putting the software under medium load.

Limitations

HTTPS is not supported and pages using SPDY might cause problems.