Fiddler(core) - modify built-in pac script

Question

I noticed today that Fiddler has the ability to deliver a PAC file rather than setting its self up as a system-wide proxy. For example if you set your autoconfig URL in Internet Explorer to http://localhost:8888/proxy.pac fiddler delivers the following:

HTTP/1.1 200 OK Content-Length: 275 Content-Type: application/x-ns-proxy-autoconfig Cache-Control: max-age=60 Connection: close

// Autogenerated file; do not edit. Rewritten on attach and detach of Fiddler.

// Get the URL to this file from Fiddler by clicking Tools > Fiddler Options > Connections > Copy Browser Proxy Configuration URL.

function FindProxyForURL(url, host){ return 'DIRECT'; }

I would however like to edit this file so that I can choose which websites I would like to send to fiddler for debugging.

The reason for this is that sometimes I find Fiddler slows down my internet browsing (possibly due to issues with my Fiddler Script) and having the ability to bypass Fiddler for other sites that i'm not debugging would be really handy.

Answer 1

Fiddler's default script body is return 'PROXY 127.0.0.1:8888';

You can change this by setting a preference:

FiddlerApplication.Prefs.SetStringPref("fiddler.proxy.pacfile.text", "your script body goes here...");