Controlling source IP address within urllib2

[Dan]

Does anybody know how to control the source IP address (IPv4) when
using the urllib2 library? I have a Linux box with several IP
addresses in the same subnet, and I want to simulate several
individuals within that subnet accessing web pages independently. I
need the functionality of urllib2 because there will be redirects and
other HTTP-type functions to implement. It would be nice if I could
create (and bind) sockets myself and then tell the urllib functions to
use those sockets. Perhaps there is some sort of "back-door" way of
doing this??? Any hints are appreciated!
-Dan

[Dan]

John,
Thanks for your input. I can kind of see the light in this, but I'm
having difficulty knowing where the "do_open" method comes from. Also,
I'll need to follow redirects, so I assume then I would add a
HTTPRedirectHandler instance to the urllib2.build_opener. (?) Thanks
again for your help.
-Dan

[John J. Lee]

"Dan" <to****@hotmail.com> writes:

John,
Thanks for your input. I can kind of see the light in this, but I'm
having difficulty knowing where the "do_open" method comes from. Also,
AbstractHTTPHandler

I'll need to follow redirects, so I assume then I would add a
HTTPRedirectHandler instance to the urllib2.build_opener. (?) Thanks

No. It does that by default.
John

[Dan]

John,
Thanks again for your help!
I think that the do_open function in AbstractHTTPHandler does not
return the correct object type as required by the opener. When I
include the code you recommended, the implementation comes back with
the message, "urlopen error unknown url type: http". Strange, because
I would think that overriding the "http_open" function in the handler
would have signaled that this function is capable of handling http. If
I call the HTTPHandler base class "http_open" function from within the
derived class, all works okay, but of course, I don't get to use the
source IP address I wanted to use.
I'll keep trying and let you know what I find.
-Dan

[Dan]

Just FYI ... I finally got this to work. Unfortunately, I was unable
to use the urllib2 library. The embedded Linux team here informed me
that the urllib2 library will not be available on the machine I wanted
to deploy on, so I had to go back to using the urllib and httplib
libraries. After trying several things, I finally gave up and hacked
the library code directly. It turned out to be quite easy. I just had
to wedge in a "self.sock.bind()" call in front of the
"self.sock.connect()" call within the HTTPConnection class inside the
httplib library. (I used the bind() function to nail down the source
IP address of the client.) Of course, I had to weave in some code that
allowed me to pass the client IP address through the URLopener class in
the urllib library. Everything seems to work so far.

John, thanks again for your help. You pointed me in the right
direction.

-Dan