Install Python and Web development tools

Python Django Flask Tornado Pyramid

In this post you can learn how to install and configure Python and web development tools like Django, Tornado, Flask and Pyramid, to implement web applications.

Python is one of the most used programming languages. Above all, there are a lot of reasons to learn and use Python as a multi-purpose development tool:

  • Easy to Learn and Use: It is developer-oriented and high level.
  • Expressive: The syntax is more understandable and readable.
  • Interpreted: Easy to run and debug, suitable for beginners.
  • Cross-platform: Python is portable. You can install and run it in Windows, Linux, Unix and Mac. Also, there are several other ports.
  • Free and Open Source:The source-code is also available.
  • Object-Oriented: Python supports OOP with classes and objects.
  • Multi-paradigm: You can use procedural, object-oriented and functional programming paradigms.
  • Extensible: You can compile and integrate new libraries and tools using languages like C/C++.
  • Large Standard Library: Extensive functionality through a huge collection of modules and libraries through a package/module manager (pip) .
  • GUI Programming: You can implement Graphical user interfaces using Python, for desktop and web applications.
  • Integrated: You can easily integrate  Python with languages like C, C++, JAVA etc.

Installing Python

MacOS Installation

Python is already installed along with other development tools in latest MacOS releases. However, you need to install additional packages and tools to get a lot of new functions available to start a new python development process. First of all, check your current python version:

python -V

Normally, Python 2.7 is installed. However, it’s a basic installation and you probably need more than the core Python packages. First of all, you need to install the core development tools for MacOS, including C/C++ compilers:

xcode-select --install

This command will install and configure basic development tools to compile some packages that will be needed in the next sections. You also may need to configure additional development tools like Homebrew and MacPorts  before, to continue the installation process.

Install Python using HomeBrew

brew install python@2

This will install Python, setup tools(like easy_install) and pip.  easy_install is an installation utility to setup and install remote packages. pip is a complete package manager and installer for Python, recommended over easy_installwith several additional features. Also, the installation will create links like python2, to allow installation of additional python version 3 (default current version), running as python3.  You can install this version using HomeBrew.

brew install python

Now you have 3 commands available: python for the latest version available (v3.7), python2 for version 2.7 and python3 for version 3.7. This could help when you need a specific version to run a specific tool or application. Then, to make sure your default python command points to the latest version installed, you need to add the following path to your ~/.bash_profile:

export PATH="/usr/local/opt/python/libexec/bin:$PATH"

Actually, this path /usr/local/opt/python/libexec/bin contains all the current version links for python.

Linux Installation

On Debian-based systems (Ubuntu), use APT:

sudo apt-get install python3

For Red Hat-based systems, use yum:

sudo yum install python

In SUSE-based distributions, use zypper:

sudo zypper install python3

 

Install Django

Django is a high-level Python Web framework that encourages rapid development and clean, pragmatic design. The simplest way to install Django is using the pip command line:

pip install Django

After installing Django, you can use the Django command django-adminto create a new Django project structure:

django-admin startproject [projectname]

And then, start your web development server with the command:

cd projectname
python manage.py runserver

 

Install Tornado

Tornado is another Python web framework and asynchronous networking library. By using non-blocking network I/O, Tornado can scale to tens of thousands of open connections, making it ideal for long polling, WebSockets, and other applications that require a long-lived connection to each user. You can install Tornado using the pip command:

pip install tornado

This is a basic “hello world” example Web application using tornado:

import tornado.ioloop
import tornado.web

class MainHandler(tornado.web.RequestHandler):
  def get(self):
    self.write("Hello, world")

  def make_app():
    return tornado.web.Application([
      (r"/", MainHandler),
    ])

  if __name__ == "__main__":
    app = make_app()
    app.listen(8888)
    tornado.ioloop.IOLoop.current().start()

Also, there is an asynchronious websockets example in the Github project page.

Install Pyramid

Pyramid is another Web framework for Python. You can start small with this “hello world” minimal request/response web app. This may take you far, especially while learning. As your application grows, Pyramid offers many features that make writing complex software take less effort.

from wsgiref.simple_server import make_server
from pyramid.config import Configurator
from pyramid.response import Response

def hello_world(request):
    return Response('Hello World!')

if __name__ == '__main__':
    with Configurator() as config:
        config.add_route('hello', '/')
        config.add_view(hello_world, route_name='hello')
        app = config.make_wsgi_app()
    server = make_server('0.0.0.0', 6543, app)
    server.serve_forever()

You can install pyramid using the pip command:

pip install "pyramid==1.10.1"

Install Flask

Flask is a Web microframework for Python based on Werkzeug and Jinja 2. Its features are basically: built-in development server and debugger,  integrated unit testing, RESTful request dispatching, Jinja2 templating, and secure cookies (client side sessions). This is a simple “Hello World” to start a project:

from flask import Flask
app = Flask(__name__)

@app.route("/")
def hello():
  return "Hello World!"

To setup and run a local server:

pip install Flask
FLASK_APP=hello.py flask run

 

Note: This article was originally posted on https://developerhowto.com/2018/10/31/install-python-and-web-development-tools/

 

 

 

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