web application firewall development
OK, so my guess was basically correct, although I thought it was protecting an app with no or bad security, but it's more about protecting against attacks. In that Case, Django is definitely wrong. It's clearly doable in Python, but don't expect to be able to handle 100.000 requests per second. :) But if it's research and development, I think Python can be a great choice, as it's fast to develop in, and with tools like Cython it can be quite fast to run as well. Should you then end up making a finished product that does need extreme performance, you can take the algorithms and translate them to C/C++.
I'd look into Twisted in your case. That may be the correct solution. 

"It will be used on the server side to control the user transactions via HTTP."
Most web application frameworks have security settings. These are usually not called "firewalls", and you didn't answer my questions, so I'm going to guess here:
You are writing a web proxy that will act to filter out requests which do not have the correct permission because there is an application which does not have any access control at all. Is this correct?
Yes, you can do that in Python. Django is probably not the correct solution. If you need to implement access control with login pages and user management, then you probably want SQL and templating and a lightweight Python framework could be helpful. Otherwise Twisted or just doing it with the functionality in standard lib might be the correct solution.
I have an assignment to develop a web application firewall. I have been researching for some source codes about that.My main source was ModSecurity.
Main question is that:
-Which framework or programming language I can use, to develop a web application firewall? Which one would be the most useful?
-Can I use Django & Python?
It would be a starting point for the project research.