A python website no framework needed part 1

#python #webdev

Why would you want to build a website using python with no framework here is some reasons :

you want to understand how this flask , django works
want to build your own framework in the future
you like to build things from scratch

writing a simple python website without a framework is easy if you just want some basics features,
but if you want more advanced features like routing, database connection, validate forms, and add your own template engine then things will become difficult bit by bit

Requirements

requirements or what you need to know before you can start doing this

a basic knowledge about http protocol, this is some resources if you want to learn more about how http work :

MDN Basics of HTTP

W3School HTTP Request Methods
what WSGI is? , some resources if you want to know :
An Introduction to the Python Web Server Gateway Interface

What is WSGI
how to serve a python web app using something like gunicorn , gevent

A simple hello World

here a simple example of a hello web python application

def app(environ, start_fn):
    start_fn('200 OK', [('Content-Type', 'text/plain')])
    return ["Hello World!\n"]

but how to run this ? , first we need to install gunicorn or gevent or something similar, for me i choose gevent because gunicorn will not work with windows.

Installing genvent

pip install gevent

Running the app

we need to import the gevent wsgi class to serve the app

....

if __name__ == '__main__':
    from gevent.pywsgi import WSGIServer
    WSGIServer(('', 8000),app, spawn=None).serve_forever()

want to know why we use

if __name__ == '__main__':

check this stackoverflow answer by Jack

our code will look like this now

def app(environ, start_response):
        data = b"Hello, Web!\n"
        start_response("200 OK", [
            ("Content-Type", "text/plain"),
            ("Content-Length", str(len(data)))
        ])
        return iter([data])


if __name__ == '__main__':
    from gevent.pywsgi import WSGIServer
    WSGIServer(('', 8000),app, spawn=None).serve_forever()