[Filterproxy-devel] Re: FilterProxy-0.30 and upstream auth proxy problem

[Bob M. <mce...@dr...>]

John Straw [joh...@be...] wrote:
> Bob McElrath writes:
>  > Could you try commenting out the line:
>  >     $agent  -   env_proxy();    # process http_proxy environment varia=
ble
>  > in FilterProxy.pl and see if it fixes your POST problem?  From my
>  > reading of LWP::UserAgent, it won't, but it should.  *then* we should
>  > file a bug.  ;)  This is an easy fix though, maybe I'll submit a patch
>  > against LWP.
>=20
> I tried the following:
>=20
> 1. reset the http_proxy variable in the FilterProxy.conf file to point
> at my upstream proxy, _without_ the username:password hack.
> http_proxy_user and http_proxy_password are still set in the file.
>=20
> 2. comment out the line in FilterProxy.pl
>=20
> 3. restarted FilterProxy.
>=20
> No change in behavior.  The only thing that works for me (that I know
> about) is the username:password hack, which gets around the fact that
> LWP chokes on the 407 return when performing a POST.
>=20
> (I'm confused about what effect you expect this change to have,
> though, because when FilterProxy has no http_proxy environment
> variable set when I start it (now))

LWP doesn't actually call the get_basic_credentials method when it
encounters a proxy-authorization challenge.  This is basically the bug.
However if the proxy info is set via the http_proxy environment
variable, it is able to get that info correctly.

It kinda makes sense that it should work this way though.  Otherwise how
would you access a website that needed authorization, through a proxy
that needed a *different* authorization?  (get_basic_credentials is what
is used to get the user/pass for regular 'ol non-proxy HTTP basic
authorization)

I can modify FilterProxy to do this automatically, and work with the
data on the config page.  So based on all this I have added to my TODO
file:
  =20
* Check http_proxy environment var and ignore it if it points to me.=20
* Print out what upstream proxy is geing used on startup.
* Prefer config-page entered upstream proxy/user/pass to environment=20
    variable http_proxy if they differ.
* When upstream proxy requires authentication, construct:
        http_proxy =3D http://user:pass@host:port/
    and pass this to $agent->proxy() rather than using get_basic_credential=
s.
    (HTTP authorization challenges should be passed back to browser)
* Investigate HTTP/1.1 and connection cache in LWP/Protocol/http.pm
    do not any more remove keep-alive and other HTTP/1.1 headers?
=20
>  > LWP man page:
>  >     PERL_LWP_USE_HTTP_10
>  > I guess it is using HTTP/1.1 now...that's new.  ;)  I shall have to
>  > investigate further, this could speed up FilterProxy a bit.  Oooohhh...
>  > it looks like it now can keep a connection cache and re-use connections
>  > to upstream servers!  ;)
>=20
> I thought I had seen some stuff about 1.1 in there.  I'll be glad if
> my fumbling leads to productive hacking!

;)  Prolly not for a while.  I'm sooooo busy these days...

If you feel like hacking some perl, go ahead, I prolly won't get to this fo=
r a
while.

Cheers,
-- Bob

Bob McElrath (rsm...@st...)=20
Univ. of Wisconsin at Madison, Department of Physics