Re: External filter never executes

--===============6211610223184971198==
Content-Type: multipart/signed; boundary="Sig_/ks8kOy/PIw=5hErY9=4=x6L";
 protocol="application/pgp-signature"; micalg=pgp-sha256

--Sig_/ks8kOy/PIw=5hErY9=4=x6L
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: quoted-printable

Tibor Pataky via Privoxy-users <[email protected]> wrote on 2=
025-08-17 at 16:25:59:

> I've only just recently discovered privoxy and I thought I'll give it a t=
ry!

Great.

> One thing I can't get to work though is external filters (perhaps any
> filters at all?).
> I stripped down the config as much as possible, my user.action and
> user.filter files look like this:
> user.action:
> { +external-filter{my-filter} }
> /
>=20
> user.filter:
> EXTERNAL-FILTER: my-filter why you no work?
> /usr/bin/tee /var/tmp/privoxy/out
>=20
> When I run privoxy with: --no-daemon /etc/privoxy/config
> and run the following: curl --proxy localhost:8118 https://www.privoxy.or=
g/
> I get the following output:
> 2025-08-17 15:01:41.411 7ad19d4f0740 Info: Privoxy version 4.0.0
> 2025-08-17 15:01:41.411 7ad19d4f0740 Info: Program name:
> /workdir/privoxy/privoxy
> 2025-08-17 15:01:41.413 7ad19d4f0740 Error: Config option single-threaded
> disables connection keep-alive.
> 2025-08-17 15:01:41.413 7ad19d4f0740 Info: Loading filter file:
> /etc/privoxy/user.filter
> 2025-08-17 15:01:41.413 7ad19d4f0740 Re-Filter: Reading in filter
> "timed-filter" ("why you no work?")
> 2025-08-17 15:01:41.413 7ad19d4f0740 Info: Loading actions file:
> /etc/privoxy/user.action
> 2025-08-17 15:01:41.413 7ad19d4f0740 Info: Listening on port 8118 on IP
> address 0.0.0.0
> 2025-08-17 15:01:48.322 7ad19d4f0740 Request: www.privoxy.org:443/
> 2025-08-17 15:01:48.322 7ad19d4f0740 Actions: +external-filter{my-filter}
>=20
> This deceptively shows that it executes my-filter, but it never actually
> runs the tee command, the file under /var/tmp/privoxy never appeared.

Actually the "Actions:" message only shows that the external-filter{} action
"applies".

To actually execute any filters Privoxy has to buffer the content and it
looks like you didn't enable HTTPS inspection so Privoxy isn't doing that.
=20
> I got to the point where I built privoxy from source (the v_4_0_0 tag) wi=
th
> debug symbols and ran it under gdb.
> I set various breakpoints in handle_established_connection, but couldn't
> really figure out what is going wrong. What I noticed is that the variable
> buffer_and_filter_content which guards the call to execute_content_filters
> is only ever set where it is declared. The main loop in
> handle_established_connection exits after a couple of iterations when it
> runs onto the break statement at line 3413. As far as I can tell the only
> place where buffer_and_filter_content is possibly set to a nonzero value =
is
> in line 4111, but execution never reaches this line.
>=20
> At this point I'm really out of ideas what to try next...

For a quick test, try a http:// URL.

> Is there some extra config I forgot to set to enable external filters?

As mentioned above, to filter https:// content you have to enable
HTTPS inspection. There's a HOWTO at:
<https://www.privoxy.org/user-manual/howto.html#H2-HTTPS-INSPECTION>

> Is it a header that's behind this?

No.
=20
> What should I check for in gdb?

Enabling HTTPS inspection should be sufficient to solve this without
involving gdb.

Don't forget to remove the single-threaded directive again as it results
in poor performance.

Fabian

--Sig_/ks8kOy/PIw=5hErY9=4=x6L
Content-Type: application/pgp-signature
Content-Description: OpenPGP digital signature

-----BEGIN PGP SIGNATURE-----
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=Vt7p
-----END PGP SIGNATURE-----

--Sig_/ks8kOy/PIw=5hErY9=4=x6L--

--===============6211610223184971198==
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: inline

_______________________________________________
Privoxy-users mailing list
[email protected]
https://lists.privoxy.org/mailman/listinfo/privoxy-users

--===============6211610223184971198==--