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🌐 Day 35: Flask Web Framework

Welcome to Day 35! This lesson contains a small Flask project that analyses submitted text and reports simple statistics such as word counts and lexical diversity.

Environment setup

  1. Create and activate a virtual environment (recommended): 
    python -m venv .venv
source .venv/bin/activate  # On Windows use: .venv\\Scripts\\activate
  2. Install the dependencies for this lesson: 
    pip install -r Day_35_Flask_Web_Framework/requirements.txt

Running the Flask application

The application now exposes a create_app() factory in Day_35_Flask_Web_Framework/app/__init__.py, so it can be started with the Flask CLI:

FLASK_APP=Day_35_Flask_Web_Framework.app:create_app flask run

Alternatively, you can execute the module directly:

python -m Day_35_Flask_Web_Framework.app

Once running, visit http://127.0.0.1:5000/ to interact with the analyser. Use the Post page to submit text and review the calculated statistics on the Result page.

Running the tests

Automated tests validate both the Flask routes and the helper functions that power the analyser. Execute them from the repository root:

pytest -k day_35

💻 Exercises: Day 35

  1. Create a new route:

  2. Add a new route to the create_app factory at the URL /about.

  3. Create a view function that returns a simple string, like "This is the about page."

  4. Create a new template:

  5. Create a new HTML file named contact.html in the templates directory.

  6. Add a new route to the Flask app at the URL /contact that renders the contact.html template.

  7. Pass data to a template:

  8. Modify the /about route to pass your name to a new about.html template.

  9. In the about.html template, display the name that was passed from the view function.

Solutions

You can find the solutions to these exercises in the solutions.py file in this directory.

🎉 Congratulations! You've learned the basics of Flask, a powerful tool for building web applications and dashboards with Python.

Previous: Day 34 – Day 34: Building a Simple API with Flask • Next: Day 36 – Day 36 – Capstone Case Study

You are on lesson 35 of 108.

Additional Materials

solutions.py

View on GitHub

solutions.py
# Day 35: Flask Web Framework - Solutions

from flask import Flask, render_template

app = Flask(__name__)

## Exercise 1: Create a new route


@app.route("/about-solution")
def about_solution():
    return "This is the about page."


## Exercise 2: Create a new template

# 1. Create a new HTML file named 'contact.html' in the 'templates' directory.
#    You can add some simple content to it, like:
#
#    <!DOCTYPE html>
#    <html>
#    <head>
#        <title>Contact Us</title>
#    </head>
#    <body>
#        <h1>Contact Us</h1>
#        <p>You can contact us at contact@example.com</p>
#    </body>
#    </html>
#
# 2. Add a new route to app.py that renders this template.


@app.route("/contact")
def contact():
    return render_template("contact.html")


## Exercise 3: Pass data to a template

# 1. Create a new HTML file named 'about.html' in the 'templates' directory.
#
#    <!DOCTYPE html>
#    <html>
#    <head>
#        <title>About Me</title>
#    </head>
#    <body>
#        <h1>About {{ name }}</h1>
#    </body>
#    </html>
#
# 2. Modify the '/about' route to pass your name to the template.


@app.route("/about-me")
def about_me():
    my_name = "Jules"  # You can replace this with your name
    return render_template("about.html", name=my_name)


if __name__ == "__main__":
    import os

    # Skip running the server in test/automated environments
    if os.environ.get("FLASK_RUN_TEST_MODE") != "1":
        app.run(debug=True)
    else:
        print("Flask app created successfully (test mode - not starting server)")
        print("Routes available:")
        print("  - GET /about-solution")
        print("  - GET /contact")
        print("  - GET /about-me")