talkpython/data-driven-web-apps-with-flask

Course demo code and other hand-out materials for our data-driven web apps in Flask course

Data-driven web apps with

Course demo code and other hand-out materials for our data driven web apps in Flask course. Visit the full course page at training.talkpython.fm

Course Summary

One of the areas Python really shines is in building clean and powerful web applications. Once you know the language basics, this course will teach you everything you need to build data-driven, modern web applications in Python with the Flask web framework.

What's this course about and how is it different?

Full stack web development is exactly what you need to build true data-driven web applications in Python. Yet these courses can be confusing and overwhelming due to the many technologies involved (Python, SQL, CSS, etc).

We have taken great care to build a course that is just real enough to give you what you need without anything extra. We build a replica of a popular web application, Python's own packaging index over at pypi.org.

While building our replica PyPI, you will learn:

• Learn about the different major Python web frameworks
• Create a Flask-based website from scratch using the CLI and PyCharm
• Work with dynamic HTML templates
• Map URLs to view methods using routing
• Make advanced use of routing to build a full custom CMS in 8 minutes
• Take advantage of bootstrap to build well designed sites
• Map data to and from Python using classes with SQLAlchemy
• Learn how Alembic can help our database evolve as our models change
• Accept user input with HTML forms
• Add client and server-side validation
• Overcome the special challenges of testing web apps (databases, frameworks, etc)
• Deploy our web application to a fresh Linux machine (virtual, cloud-based)
• Leverage our design patterns to convert our app to another data model (MongoDB edition)

Who is this course for?

This course is for anyone who wants to create Python-based web applications using the Flask web framework. In fact, you'll learn a lot of web skills that will translate across frameworks as well.

We do assume that you have basic Python language skills and can read HTML and CSS. But most advanced uses of the language or CSS are explained in the course.

Is this course based on Python 3 or Python 2?

This course is based upon Python 3. With Python 2 going unsupported in 2020, we believe that it would be ill-advised to teach or learn Python 2.

The time to act is now

This data-driven web apps with Python and Flask course is just what you need to build that fast, custom web application that can help you create your next great idea or just solve a business problem by deploying it behind your firewall.

Take the course over at training.talkpython.fm.

data-driven-web-apps-with-flask's Issues

Update certbot https instructions

Hey there,

I ran into an issue with the SSL certbot install when revisiting this tutorial for another project I am doing (so I am not following the lesson to the tee here... and maybe the issue is just me 😁 ). The PPA install has been deprecated

# add-apt-repository ppa:certbot/certbot

PPA publishes dbgsym, you may need to include 'main/debug' component
Repository: 'deb https://ppa.launchpadcontent.net/certbot/certbot/ubuntu/ kinetic main'
Description:
The PPA has been DEPRECATED.

Following the instructions from certbot worked for me on Ubuntu 22.1

sudo snap install core; sudo snap refresh core
sudo snap install --classic certbot
sudo ln -s /snap/bin/certbot /usr/bin/certbot

Chapter 07

When the Login button is clicked with empty fields the video shows that password field turns red. This does occur when using Firefox but it does not occur when using Safari on the Mac.

Not a bug per se, but something that may confuse users.

Bluebrint causes 404 not found

I ran the code from the command line in the final folder of ch06_routing using flask run but get 404 not found for both the homepage and the about page. This was the same when I followed along. The app worked fine before I added the blueprint.

I have a windows 10 machine with python 3.7.3 and I'm using a virtual environment.

List does't not have attribute lower() error on requestdict

Some folks are experiencing issues where they are getting a list rather than plain dict. I think it's from multiple entries in the multidict. Converting to a regular dict will fix it.

Expected dictionary got response error

Some people are running into issues where the @response() decorator doesn't filter werkzeug responses correctly.

Ch 12 - Forms - sqlite3.ProgrammingError: SQLite objects created in a thread can only be used in that same thread.

I'm getting this error when I run app.py at the beginning and navigate to any of the package pages.

sqlite3.ProgrammingError: SQLite objects created in a thread can only be used in that same thread. The object was created in thread id 123145425145856 and this is thread id 123145430401024.

Above it getting this repeating error:

Traceback (most recent call last):
  File "/Users/danielmsheehan/GitHub/data-driven-web-apps-with-flask/venv/lib/python3.7/site-packages/sqlalchemy/pool/base.py", line 693, in _finalize_fairy
    fairy._reset(pool)
  File "/Users/danielmsheehan/GitHub/data-driven-web-apps-with-flask/venv/lib/python3.7/site-packages/sqlalchemy/pool/base.py", line 880, in _reset
    pool._dialect.do_rollback(self)
  File "/Users/danielmsheehan/GitHub/data-driven-web-apps-with-flask/venv/lib/python3.7/site-packages/sqlalchemy/engine/default.py", line 538, in do_rollback
    dbapi_connection.rollback()

To start each I chapter I start by renaming the final folder to final_, This is from copying the starter folder code and naming it final and then working in that directory.

I didn't see this error in chapter 11, (and I re-ran app.py to test - not seeing this error in ch. 11). I'm thinking there may be something different in ch 12's code, maybe something was added that after following along will be updated. If so I'll close this, otherwise not sure what to do. If this is in Chapter 13 as well and persists, I'll note that here.

Refactoring view methods with blueprints

Cannot figure out why everything stops working at the moment when I switch app.py over to use blueprints. I am copying what you do in the video, but when i run app.py, I get a 404 return.

As soon as i switch back to original app.py setup, this work again.

Upgrade to sqlalchemy 2.0?

I don't really know much about sqlalchemy, but I did hear on your podcast that they have a big new version out. How hard would it be to update this project to use the new features/patterns in sqlalchemy 2.0?

Maybe like, one final extra video in the course or something... like an epilogue?

Small error in order of lines in code: Chapter 10 - basic_inserts.py

There is a small error in basic_inserts.py. It probably went unnoticed because it only affects folks that are not using Pycharm. Here's the problem:

import pypi_org.data.db_session as db_session
from pypi_org.data.package import Package
from pypi_org.data.releases import Release

Make it run more easily outside of PyCharm

sys.path.insert(0, os.path.abspath(os.path.join(
os.path.dirname(file), "..", "..")))

The code to fix the problem with the system path needs to be place before the imports.

Thanks for the course. I am slogging along steadily.

Cheers!
Alex in Valrico, Florida

PS: Still not haven't worked out how to do pull requests.

Pre-create db folder for users

Some users are reporting this error because they have not created the db folder first. Not sure whether this was missed or just not emphasized enough in the course but it's no big deal to create that folder in the starter code to help smooth things over:

sqlalchemy.exc.OperationalError: (sqlite3.OperationalError) unable to open database file
(Background on this error at: (link: http://sqlalche.me/e/e3q8) sqlalche.me/e/e3q8)

During Lesson 09 > Creating tables.

Could be an issue on my end, but the only way I found to make it work is to create the db folder myself.

db not creating - Similar to Blueprint 404 issue

Hello! Similar to the previously-noted Blueprint 404 issue which was corrected with:

register_blueprints()
if __name__ == '__main__': main()

I'm now seeing an issue with the db not creating because setup_db is not being accessed. I moved setup_db here:

register_blueprints()
setup_db()
if __name__ == '__main__': main()

... and still nothing, but at least it prints out the connection string. Any ideas for how to solve this?

Ch 10, Video 7 - Inserting the real Pypi data - where's the load_data.py file?

the video starts saying we aren't going to write the load_data.py file, but it does not mention where to find it to bring it in to the project
Copying the load_data.py file from the final folder and trying to run it along with this video gives the error:

Traceback (most recent call last):
File "C:/PyWorkspace/data-driven-web-apps-with-flask/app/ch10_using_sqlachemy/starter/pypi_org/bin/load_data.py", line 16, in
from pypi_org.infrastructure.num_convert import try_int
ModuleNotFoundError: No module named 'pypi_org.infrastructure.num_convert'

is there a different load_data.py file we should use here?

Able to manually enter hhtp://.../account/login in the address bar when a user is already logged in.

If a user is already logged in, they can manually go to the login page even after they are already logged in. Instead, manually going to the login page if logged in should redirect to the account page.

ModuleNotFoundError: No module named 'pypi_org' error

I am having trouble with the Jinja2 templates and the routing and URLs tutorials.

When I follow your code and use:

from pypi_org.infrastructure.view_modifiers import response
import pypi_org.services.package_service as package_service

I get the error:
ModuleNotFoundError: No module named 'pypi_org'

The error doesn't occur when I change the code to:

from infrastructure.view_modifiers import response
import services.package_service as package_service

What am I doing wrong?

ModuleNotFoundError: No module named 'pypi_org'

I'm in ch06_routing and trying to setup the blueprints. register_blueprints is throwing the error:

ModuleNotFoundError: No module named 'pypi_org' all of the imports.

For example from pypi_org.views import home_views and from pypi_org.views import package_views both cause the error. I do have a views directory inside of the pypi_org directory, and app.py is at the root of pypi_org.

Inside of the views directory the import of services does not cause this error (import pypi_org.services.package_service as package_service runs with no error).

I can't figure out why I am getting the error in the app.py file.