How to Use WTForm / Flask-WTF Custom Validators (Simple Example) - Chat App Part6

In this video, we see an example of how to use an inline custom validator with WTForms/Flask-WTF. This is part 6 of the 13 part code-along video series on creating a chat application. Resources: Download source file: https://github.com/sandeepsudhakaran/rchat-app Live link to final chat app: https://rchat-app.herokuapp.com/ Links referenced in the video: WTForms: https://wtforms.readthedocs.io/en/stable/ Flask-WTF: https://flask-wtf.readthedocs.io/en/stable/ Videos in this series: Part 0. Intro video: https://youtu.be/pvUUidK1zuw Part 1. Setup virtual environment, Heroku & PostgreSQL: https://youtu.be/eNZ8ZS88F4M Part 2. Create basic Flask app: https://youtu.be/wO7a7R5GGA8 Part 3 . Add a basic form to the page using WTForms: https://youtu.be/EpJRJsmqnn0 Part 4. Cleaner code with WTForms Macros: https://youtu.be/HY0le1NAczc Part 5. Use SQLAlchemy and Flask-SQLAlchemy to connect form to PostgreSQL database: https://youtu.be/7EeAZx78P2U Part 6. Custom validator for WTForms/Flask-WTF: This video Part 7: Create a login page: https://youtu.be/DbAKzi0kR80 Part 8: Hashing with PBKDF2 / Passlib: https://youtu.be/U7FaYdxZLA4 Part 9. Session management with Flask-Login: https://youtu.be/rrIdQJSKiP4 Part 10. Use Flask's message flashing: https://youtu.be/wQXSDwCgXIQ Part 11. Introduction to Polling, WebSocket & Socket.IO: https://youtu.be/sUEq35F-ELY Part 12. Use Flask-SocketIO to create app: https://youtu.be/zQDzNNt6xd4 Part 13. Deploy Flask app in Heroku: https://youtu.be/FWU_tJqr1Po