Simple Flask Template App

This short code repository shows how a Flask application that serves HTML files may be created.

It is used in our blog post, "How to add user logins to your Flask website". Read that for more info!

Installing

You'll need flask to run this code sample. Install it like so:

pipenv install flask

The app

Creating a Flask app is simple. Here we create one and also give it a secret_key. This is used for securing the cookies that the Flask app sends to each user.

from flask import Flask, render_template, session

app = Flask(__name__)
app.secret_key = "jose"

The users

In this Flask application we have a list of users. We use these to implement authentication (login and signup) in the app. We do that in the blog post.

users = {"jose": ("jose", "1234")}

This is a mapping of usernames to user data. This allows us to access users[username] when a user sends us their username.

It means we won't have to search through a list of users when we get a user's username.

The routes

We have three pages in this starter app: home, login, and register.

At the moment these only return HTML pages (from the templates folder). In the blog post we modify two of them to actually deal with user data.

@app.route("/")
def home():
    return render_template("home.jinja2")


@app.route("/login")
def login():
    # Here you could deal with the user's username and password.
    # Check if they're correct.
    return render_template("login.jinja2")


@app.route("/register")
def register():
    # Here you could register the user.
    # Add them to a database, for example.
    return render_template("register.jinja2")

Running the app

To run this app, enter the Pipenv shell and run the app via the Flask CLI. Make sure you're in the correct directory first:

pipenv shell
flask run