Lecture 2⁵

Using Flask

MCS 275 Spring 2023
David Dumas

Reminders and announcements:

Please install Flask, e.g. with
```
python3 -m pip install Flask
```
in preparation for using it in upcoming assignments.
Start work on Project 4
Homework 12 posted

Build the worker view template

Create the database and link it to the Flask application

Single table orders with columns:

woid - integer uniquely identifying a WO
description - string
assigned_user - either
- username this WO is assigned to
- NULL if not assigned
created_ts - "created timestamp" as time.time()
assigned_ts - "assigned timestamp", either:
- time.time() when assigned
- NULL if not assigned
completed_ts - "completed timestamp"
- time.time() when completed
- NULL if not completed

A row only makes sense if created_ts is not NULL, and if assigned_ts and assigned_user are either both NULL or both non-NULL.

Route /worker/ddumas/ results in:

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.