Flask: Templates

Using Jinja 2 Templates with Flask

Perhaps read these first

You may find it helpful to read the following pages before this one.

Common Navigation
Flask

Resources on templates

From the quickstart: http://flask.pocoo.org/docs/0.12/tutorial/templates/
From the longer tutorial: http://flask.pocoo.org/docs/0.12/quickstart/#rendering-templates
The documentation: http://flask.pocoo.org/docs/0.12/templating/
From Miguel Grinberg’s Flask Megatutorial: https://blog.miguelgrinberg.com/post/the-flask-mega-tutorial-part-ii-templates

Why use templates?

When making a website with a web framework, we quickly run into two issues:

It is helpful to keep HTML code and program code (e.g. Python code) separate.

Our tools (IDEs, editors, etc.) can help us better with our code if files that end in .py only have Python, and files that end in .html only have HTML, for example. (The same is true for .css and .js files.
HTML files have lots of repetition.

Each web page needs a <head> element, for example, and the contents of that element— lists of .css and .js files to be inclued—are often identical, or nearly so, for every page on our site.

And, there is the need for common navigation—headers, footers, etc.

Templates to the Rescue

Nearly every server side web framework has some way of doing templating, whether we are talking about PHP, Rails, Django, etc.

Some web frameworks leave templating as a separate concern, and allow the user to choose from among several different templating systems.

Technically, we can say that Flask (the framework we are using in this course) falls into this category—however, nearly all examples that use Flask in practice use a specific templating system called Jinja2. Jinja2 is so commonly used with Flask, that it’s probably easiest to just think of it as part of Flask, though in a very technical sense, they are separate packages.