I want to have simple program in python that can process different requests (POST, GET, MULTIPART-FORMDATA). I don't want to use a complete framework.
I basically need to be able to get GET and POST params - probably (but not necessarily) in a way similar to PHP. To get some other SERVER variables like REQUEST_URI, QUERY, etc.
I have installed nginx successfully, but I've failed to find a good example on how to do the rest. So a simple tutorial or any directions and ideas on how to setup nginx to run certain python process for certain virtual host would be most welcome!
Although you can make Python run a webserver by itself with wsgiref, I would recommend using one of the many Python webservers and/or web frameworks around. For pure and simple Python webhosting we have several options available:
gunicorn
tornado
twisted
uwsgi
cherrypy
If you're looking for more features you can look at some web frameworks:
werkzeug
flask
masonite
cherrypy (yes, cherrypy is both a webserver and a framework)
django (for completeness, I know that was not the purpose of the question)
You should look into using Flask -- it's an extremely lightweight interface to a WSGI server (werkzeug) which also includes a templating library, should you ever want to use one. But you can totally ignore it if you'd like.
You can use thttpd. It is a lightweight wsgi server for running cgi scripts. It works well with nginx. How to setup thttpd with Nginx is detailed here: http://nginxlibrary.com/running-cgi-scripts-using-thttpd/
All the same you must use wsgi server, as nginx does not support fully this protocol.
Related
I'm looking at the WSGI specification and I'm trying to figure out how servers like uWSGI fit into the picture. I understand the point of the WSGI spec is to separate web servers like nginx from web applications like something you'd write using Flask. What I don't understand is what uWSGI is for. Why can't nginx directly call my Flask application? Can't flask speak WSGI directly to it? Why does uWSGI need to get in between them?
There are two sides in the WSGI spec: the server and the web app. Which side is uWSGI on?
Okay, I think I get this now.
Why can't nginx directly call my Flask application?
Because nginx doesn't support the WSGI spec. Technically nginx could implement the WSGI spec if they wanted, they just haven't.
That being the case, we need a web server that does implement the spec, which is what the uWSGI server is for.
Note that uWSGI is a full fledged http server that can and does work well on its own. I've used it in this capacity several times and it works great. If you need super high throughput for static content, then you have the option of sticking nginx in front of your uWSGI server. When you do, they will communicate over a low level protocol known as uwsgi.
"What the what?! Another thing called uwsgi?!" you ask. Yeah, it's confusing. When you reference uWSGI you are talking about an http server. When you talk about uwsgi (all lowercase) you are talking about a binary protocol that the uWSGI server uses to talk to other servers like nginx. They picked a bad name on this one.
For anyone who is interested, I wrote a blog article about it with more specifics, a bit of history, and some examples.
NGINX in this case only works as a reverse proxy and render static files not the dynamic files, it receives the requests and proxies them to the application server, that would be UWSGI.
The UWSGI server is responsible for loading your Flask application using the WSGI interface. You can actually make UWSGI listen directly to requests from the internet and remove NGINX if you like, although it's mostly used behind a reverse proxy.
From the docs:
uWSGI supports several methods of integrating with web servers. It is also capable of serving HTTP requests by itself.
WSGI is just an interface specification, in simple terms, it tells you what methods should be implemented for passing requests and responses between the server and the application. When using frameworks such as Flask or Django, this is handled by the framework itself.
In other words, WSGI is basically a contract between python applications (Flask, Django, etc) and web servers (UWSGI, Gunicorn, etc). The benefit is that you can change web servers with little effort because you know they comply with the WSGI specification, which is actually one of the goals, as stated in PEP-333.
Python currently boasts a wide variety of web application frameworks, such as Zope, Quixote, Webware, SkunkWeb, PSO, and Twisted Web -- to name just a few 1. This wide variety of choices can be a problem for new Python users, because generally speaking, their choice of web framework will limit their choice of usable web servers, and vice versa.
A traditional web server does not understand or have any way to run Python applications. That's why WSGI server come in. On the other hand Nginx supports reverse proxy to handle requests and pass back responses for Python WSGI servers.
This link might help you: https://www.fullstackpython.com/wsgi-servers.html
There is an important aspect which we are missing . Flask and Django are web frameworks and we build web applications out of them . uWSGI or Gunicorn process the framework files . Consider it as a software application sitting in between the Django app and Nginx . uWSGI and Nginx communicate using WSGI but there is no communication interface between Django and uWSGI . Check out this video https://www.youtube.com/watch?v=WqrCnVAkLIo
In simple terms, just think of an analogy where you are running a CGI or PHP application with Nginx web server. You will use the respective handlers like php-fpm to run these files since the webserver, in its native form doesn't render these formats.
Do i need to use NginX or am i able to host it without it?
I am developing my first django project and am at the point where i can run the app project using the command:
./manage.py run_gunicorn -c config/gunicorn
I can then view it going to:
http://127.0.0.1:8000/resources/
I would now like to try hosting it so that other PCs can access this.
Gunicorn is wsgi http server. It is best to use Gunicorn behind HTTP proxy server. We strongly advise you to use nginx.
# http://gunicorn.org/#deployment
Although there are many HTTP proxies available, we strongly advise that you use Nginx. If you choose another proxy server you need to make sure that it buffers slow clients when you use default Gunicorn workers. Without this buffering Gunicorn will be easily susceptible to denial-of-service attacks.
# http://docs.gunicorn.org/en/latest/deploy.html
Of course not. You can use lighttpd or any other web server that supports WSGI, SCGI, FastCGI or AJP. You may refer to this python documentation and django documentation, and these two questions on stackoverflow: Cleanest & Fastest server setup for Django, Differences and uses between WSGI, CGI, FastCGI, and mod_python in regards to Python? might be also helpful.
You don't need a frontend proxy; you can put a standalone webserver like gunicorn directly in production. But there are various reasons why you probably want to use a frontend webserver anyway.
I was wondering what is the advantages of mod_wsgi. For most python web framework, I can launch (daemon) the application by python directly and serve it in a port. Then when shall I use mod_wsgi?
Since I answered your other question regarding Flask, I assume you are referring to using Flask's development server. The problem with that is it is single threaded.
Using mod_wsgi, you would be running behind apache, which will do process forking and allow for multiple simultaneous requests to be handled.
There are other options as well. Depending on your particular use case I would consider using eventlet's wsgi server.
Or should I be using a totally different server?
Nginx with mod_wsgi requires the use of a non-blocking asynchronous framework and setup and isn't likely to work out of box with Pylons.
I usually go with the proxy route to a stand-alone Pylons process using the PasteScript#cherrypy WSGI server (as its higher performing than the Paste#http one, though it won't recycle threads if you have leaks...).
If you're set on using Apache and its your server (so you can compile and run Apache mod_wsgi), I'd suggest using that setup as its less maintenance to effectively utilize multiple cores. With a proxy setup, you'd have to use the mod_proxy_balancer with multiple paste processes to effectively utilize multiple cores/cpus.
If you're deploying to someone else's Apache (shared hosting), mod_proxy is generally the easier solution as its stock in Apache 2.2 and above.
Personally, I usually deploy with nginx + proxy to multiple paster processes.
I've also used mod_fastcgi + flup to great success several times now. There are a couple of recipes floating around for setting this up, but unfortunately it will probably still require some tweaking on your part to get everything working:
http://wiki.pylonshq.com/display/pylonscookbook/Production+Deployment+Using+Apache,+FastCGI+and+mod_rewrite
I'd like to serve django application on windows XP/Vista.
The application is an at hoc web interface to a windows program so it won't be put under heavy load (around 100 requests per second).
Do you know any small servers that can be easily deployed on windows to serve a django app? (IIS is not an option as the app should work on all versions of windows)
cherrypy includes a good server. Here's how you set it up to work with django and some benchmarks.
twisted.web has wsgi support and that could be used to run your django application. Here's how you do it.
In fact any wsgi server will do. Here's one more example, this time using spawning:
$ spawn --factory=spawning.django_factory.config_factory mysite.settings
And for using paste, the info is gathered here.
Of course, you could use apache with mod_wsgi. It would be just another wsgi server. Here are the setup instructions.
If you want to give Apache a go, check out XAMPP to see if it'll work for you. You can do a lightweight (read: no installation) "installation." Of course, you'll also want to install mod_python to run Django. This post may help you set everything up. (Note: I have not used python/Django with XAMPP myself.)
Edit: Before someone points this out, XAMPP is not generally a production-ready tool. It's simply a useful way to see whether Apache will work for you. Also, I saw that you're using SQLite after the fact.
Why not Apache ?
Nokia have developed a scaled down version of apache to run on their mobile phones. It supports python.
http://research.nokia.com/research/projects/mobile-web-server/
Also do you need anything else such as database support etc?