Lecture 36

Using Flask

MCS 275 Spring 2022
David Dumas

Lecture 36: Using Flask

Course bulletins:

  • Please install Flask, e.g. with
    python3 -m pip install Flask
    in preparation for using it in upcoming assignments.
  • Start work on Project 4

Today's goal

Build the worker view template

Create the database and link it to the Flask application

WorkSnap DB schema

Table orders has columns:

  • woid - integer uniquely identifying a WO
  • description - string
  • assigned_to - username this WO is assigned to (NULL if not assigned)
  • time_created - time.time() when created

Generating worker view

Route /worker/ddumas/ results in:

  • SELECT query to get ddumas assigned WOs
  • SELECT query to get unassigned WOs
  • Rearrange/format query data for use in template
  • Render a page template to format the data as in mockup

Note part of the URL is an argument. The pattern is /worker/<username>/


Buttons on the worker view form need to perform actions.

We'll make Flask routes for this, e.g. /wo/58/assign_to/ddumas/.

Requesting that URL should perform an action. But what content will it serve?


Every HTTP request results in a numerical status.

So far, we've seen 404 (NOT FOUND) and 200 (OK, generated by Flask when we return HTML).

There are also codes that instruct the browser to load another resource, e.g. 302 (FOUND).

Return flask.redirect("destination") to make this happen.


Revision history

  • 2022-04-11 Initial publication