What is Flask?

"Flask is a lightweight web application framework written in Python and based on the WSGI toolkit and Jinja2 template engine. It is BSD licensed."

.... What does this mean?
Flask is a microframework for Python that makes web development easy and fun!

• Microframework - Core is simple and extensible
• Werkzeug - Toolkit for WSGI, the standard Python interface between web applications and a variety of servers for both development and deployment
• Jinja - Renders Templates
• Conventions - templates and static files are stored in subdirectories within the application’s Python source tree, with the names templates and static respectively
• Thread Local Objects - Flask uses thread-local objects internally so that you don’t have to pass objects around from function to function within a request in order to stay threadsafe
• Web templates - Text files that contain variables and control flow statements (if..else, for, etc), and end with an .html or .xml extension

Installing Flask

• virtualenv - A useful tool that creates isolated Python development environments where you can do all your development work.

• $ sudo pip install virtualenv

• $ virtualenv flaskapp //creates a folder called flaskapp

• $ cd flaskapp
  $ . bin/activate
  $ pip install Flask

• //create this folder structure inside flaskapp/
  .
  ├── app
  │   ├── static
  │   │   ├── css
  │   │   ├── img
  │   │   └── js
  │   ├── templates
  │   ├── routes.py
  │   └── README.md

Flask workings

1. A user issues a request for a domain's root URL / to go to its home page
2. routes.py maps the URL / to a Python function
3. The Python function finds a web template living in the templates/ folder.
4. A web template will look in the static/ folder for any images, CSS, or JavaScript files it needs as it renders to HTML
5. Rendered HTML is sent back to routes.py
6. routes.py sends the HTML back to the browser

First swig from my Flask!

Download latest files from git And then add the following functionalities

1. Add an item to the menu for 'register'
2. Register is a page with a form that has a few form elements
3. Submit form to server and return the information in another page

Resources

• Flask Documentation
• Flask QuickStart!
• Flask Tutsplus
• Good Example!