The simplest complex example that I can think of to show main Flask app concepts.
All examples are in app.py. There are 3 view functions embedded, each showing a different example of how to build Flask apps.
Key concepts applicable throughout:
- View functions
- Routes
- Returning a template.
The first example is under /df. In this example, I show you how to embed a pandas.DataFrame() table inside an HTML page served up using Flask, essentially as a dump of the table.
Key concepts here:
- Jinja2 templating: (
{{ variable_name }}syntax) - Template inheritance: (
{% extends "parent.html" %}) - Styling with Bootstrap CSS
- Marking strings as safe to render: (
{{ string|safe }})
The second example is under /dfcustom. In this example, I show you how to apply custom formatting to a DataFrame rendered as an HTML table.
Key concepts here, building on top of example 1:
- Jinja2 syntax is very Python-like.
- Macros behave like Python functions.
- Looping is very Pythonic.
The second example is /bokehplot. In this example, I show you how to embed a Bokeh plot on an HTML page served up using Flask.
Key concepts here:
- Marking strings as safe to render (see above)
- Refactoring granular logic into a utility function, so that only application "business logic" remains.
- It is possible to cleverly pass strings around so that you can keep things like versioning automatically correct.