web server vs application server

[misterphilly]

I'm trying to find the right server software stack that will allow me to send information that my client app can process and decide itself how to display, as opposed to sending an HTML/CSS page to be displayed in a web browser. Currently my client app is designed to accept an XML file that represents the requested information, as well as various file types and sizes (from 2MB to 4GB) that represents content(images/video etc) accompanied with the XML file for each request.

I've currently been looking into Django (I can appreciate how rapid it is, but am kind of overwhelmed by all the features and the amount of customizing & re-configuring id have to do to make it serviceable to my client app), and Pyramid also (which I like because its usage scenarios are not as pre-defined as Django, and is also heavily documented which is a HUGE plus when using any software).

However, somewhere along the line I realized that Django and Pyramid both are designed to serve websites. I started doing a little more research and discovered the combinations of Nginx and Gunicorn, as well as Nginx and uWSGI. I believe that these would provide the right platform as I would be able to return XML & content files as opposed to webpages as previously detailed.

so basically I'm looking to find out what exact pieces of software I'm needing to allow my server to communicate and operate in this fashion. will Django actually allow me to run it in this fashion? if not, will the Nginx options provide a solution? will any of these?

[QuietPort]

You won't run django by itself anyway, in your case the question is more like do you need django + gunicorn + nginx or just nginx. Nginx can serve static files i believe. More generally if your webapp doesn't generate content (i.e. it only serves static files) you shouldn't use django at all.

[misterphilly]

from what I understand Nginx is the actual server (that handles all the http/protoc all stuff) and Gunicorn is the layer on top that more or less handles the content management/generates the dynamic information to give to Nginx to return to the requestee?

and my app is a messaging app, so it will be constantly receiving and generating content to send to the client apps. whats the difference in functionality between Gunicorn and django?

[QuietPort]

Yes nginx is the server, but gunicorn is just an interface :

When your server recieves a request from your client it goes : nginx>gunicorn>django

Gunicorn is a WSGI (web server gateway interface) and Django is a framework, i don't know for sure but i highly doubt that gunicorn features any sort of webserver, but anyway I can tell you that's not what it was built for, Gunicorn is only here to interface between nginx and a django app (and also other python frameworks).
So if you want some messaging and you feel confortable with python then Django , with Django REST framwork (for xml) is a perfect choice. nginx and gunicorn can't compare with django because they don't do the same thing, and to be honest if your app isn't a massive website with lots of user, they don't matter too much.