Re: Switch forward rules on-the-fly?

On Wednesday 10 October 2018 15:55,
Fabian Keil <[email protected]> put forth the proposition:
> Az <[email protected]> wrote:
>
> > On Sunday 7 October 2018 08:49,
> > Az <[email protected]> put forth the proposition:
> > > On Sunday 7 October 2018 07:59,
> > > Az <[email protected]> put forth the proposition:
> > > > On Sunday 7 October 2018 06:25,
> > > > Az <[email protected]> put forth the proposition:
>
> > > > > I use a text browser with Tor quite a lot and often come up against
> > > > > captchas. When this happens I usually go through a different proxy,
> > > > > but then I lose the privoxy protection. It's either that or boot X11
> > > > > and a GUI browser, find the site again and complete the captcha.
> > > > >
> > > > > Is there a way of switching from one proxy to another somehow via my
> > > > > browser that doesn't involve turning off privoxy or adding a rule for
> > > > > each site that this happens with? With my regular sites I do add
> > > > > rules to go direct or via a plain http proxy, but I don't want to do
> > > > > it for every random site that uses cloudflare etc., which seem to be
> > > > > on the increase now.
> > > > >
> > > > > I'm kind of thinking something I could add to the URL to let privoxy
> > > > > know that I need to use a different forward rule. I looked at tags,
> > > > > but I'm not sure I really understand if they could work for what I
> > > > > want.
> > > >
> > > > Well I almost had something working. I added /1234567890 on to the
> > > > end of a URL and set up a simple redirect like s@/1234567890$@@. It
> > > > worked OK for http, but of course not for https.
> > > >
> > > > Then I tried adding a subdomain 'forward-socks5.' to the start, but
> > > > it fails with this error:
> > > >
> > > > Error: pcrs command "s@forward-socks5.@@" changed
> > > > "forward-socks5.duckduckgo.com:443" to "duckduckgo.com:443" (1 hit), but the
> > > > result doesn't look like a valid URL and will be ignored.
> > > >
> > > > Why is this URL seen as an error?
> > > >
> > > > The actual URL I entered in the browser was
> > > >
> > > > https://forward-socks5.duckduckgo.com/lite/
> > >
> > > Sorry to keep answering my own questions :)
> > >
> > > I found add the https:// seems to work so far.
> >
> > OK. Redirect obviously isn't going to work, because the browser will
> > get passed to Tor again after the redirect. What I need is to
> > *rewrite* the URL without the browser knowing.
> >
> > So far the only thing I can see that may work is to add a TAG: on the
> > user agent, and have a script to change the user agent in my browser.
> > The problem is making sure that it gets changed back, or that the
> > rule has a timer. Adding weird user agents isn't a great idea though.
> >
> > Dunno. Maybe there's a better way.
>
> A better way is to use a client-specific tag that sets the
> forward-override action:
> https://www.privoxy.org/user-manual/config.html#CLIENT-SPECIFIC-TAG
> https://www.privoxy.org/user-manual/actions-file.html#FORWARD-OVERRIDE
>
> While this will affect all requests (from the IP address)
> you can set a small timeout that is sufficient to load
> the capture-using website.
>
> Fabian

Thanks for the reply.

I did see that section but I haven't tried it yet. I gather it means
first going to a CGI web page and selecting a tag, then going on to
the original blocked page?

What I'm using at the moment is a private browser window and setting
the user agent via a command line flag. Then a matching TAG: rule
sees it and forwards it. When I'm done I just close the window and
continue from where I was before.

I'm using elinks and so I've just set an action to send the current
page URL to an external script that runs the private browser window
using -no-connect in a new screen window.

Seems OK so far anyway.

--
Az