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I have a proxy server running on localhost (127.0.0.1) and i have grown tired of having to train users on how to switch proxies in firefox to bypass blocked websites.
I decided to write an addon. I wonder how to use xpcom to tell firefox to use a certain proxy eg
for http, use 127.0.0.1 port 8080.
Examples on the internet are scarce.

Thanks

Dr Deo
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1 Answers1

6

Proxy settings are stored in the preferences. You probably want to change network.proxy.type, network.proxy.http and network.proxy.http_port (documentation). Like this:

Components.utils.import("resource://gre/modules/Services.jsm");
Services.prefs.setIntPref("network.proxy.type", 1);
Services.prefs.setCharPref("network.proxy.http", "127.0.0.1");
Services.prefs.setIntPref("network.proxy.http_port", 8080);

If you need to determine the proxy dynamically for each URL, you can use the functionality provider by nsIProtocolProxyService interface - it allows you to define a "proxy filter". Something like this should work:

var pps = Components.classes["@mozilla.org/network/protocol-proxy-service;1"]
          .getService(Components.interfaces.nsIProtocolProxyService);

// Create the proxy info object in advance to avoid creating one every time
var myProxyInfo = pps.newProxyInfo("http", "127.0.0.1", 8080, 0, -1, 0);

var filter = {
  applyFilter: function(pps, uri, proxy)
  {
    if (uri.spec == ...)
      return myProxyInfo;
    else
      return proxy;
  }
};
pps.registerFilter(filter, 1000);
Wladimir Palant
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  • Thanks. I have seen this somewhere. But it has a problem of changing the proxy globally, yet i prefer it does it per page – Dr Deo May 15 '12 at 17:53
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    @DrDeo: It's generally a good idea to put this kind of thing into the question ;) I think that the only way is changing the global proxy settings when the page starts loading, from what I remember there is no proxy setting for a load group. But if the proxy selection logic is fixed then you could put it into a PAC file. – Wladimir Palant May 15 '12 at 18:41
  • @DrDeo: Looked into this, apparently I was wrong - there is a way to set the proxy dynamically for each URL. Edited my answer. – Wladimir Palant May 15 '12 at 20:28