flask-4-ds

Using Flask to create a full-featured webapp for serving data products

Two ways to run the flask app

• FLASK_APP=app.py FLASK_DEBUG=1 flask run
• python app.py with app.run() in app.py

The decorator @app.route('/<endpoint>') is used to declare functions that return html (or rendered templates) when the client requests an endpoint.

render_template helps pass raw html or rendered Jinja templates.

• it accepts data that can be used to render the page

Use url_for as far as possible to access resources under static/ for example You can also pass the function name associated with a route.

Create a SECRET_KEY using secrets.token_hex(16) from the secrets library and assign it to app.config

flask_sqlalchemy lets you declare table schemas as classes and work seamlessly with any database backend.

Then, we can fill these tables using db.session.add(<Object of table-class>) The class can be used to query data as User.query.all() or User.query.filter_by(<condition>).all()

For security, passwords must be hashed using the flask-bcrypt library. Bcrypt objects have methods like generate_password_hash and check_password_hash that are useful.

Use flask-login to manage user sessions

Useful functions

from flask import (
    Flask,                  
    render_template,
    url_for,
    flash,
    redirect,
    request
)

from flask_sqlalchemy import SQLAlchemy
from flask_bcrypt import Bcrypt

from flask_login import (
    LoginManager,
    UserMixin,
    login_user,
    current_user,
    logout_user,
    login_required
)

from flask_wtf import FlaskForm

from flask_wtf.file import FileField, FileAllowed

from wtforms import (
    StringField,
    PasswordField,
    SubmitField,
    BooleanFielda
)

from wtforms.validators import (
    DataRequired,
    Length,
    Email,
    EqualTo,
    ValidationError
)