Flask Routing

1. Setting Up Your Flask Project

Before diving into routing, make sure you have Flask installed. If not, you can install it using pip.

Step 1: Install Flask

Run the following command in your terminal:

pip install flask

Now, create a new project folder and navigate into it

mkdir flask_routing_app
cd flask_routing_app

2. Creating Your First Route

Step 2: Set Up the Flask Application

Create a Python file named app.py in your project folder and add the following code:

from flask import Flask

app = Flask(__name__)

@app.route("/")
def home():
    return "Welcome to the Home Page!"

if __name__ == "__main__":
    app.run(debug=True)

3. Running Your Flask Application

Step 3: Start the Flask Server

Run the Flask app with this command:

python app.py

Once the server is running, open your browser and navigate to http://127.0.0.1:5000/. You should see the message

Welcome to the Home Page!

4. Creating More Routes

Step 4: Add More Routes

Now, let’s add more routes to handle different pages. Modify your app.py file

@app.route("/about")
def about():
    return "This is the About Page."

@app.route("/contact")
def contact():
    return "This is the Contact Page."

5. Using Dynamic Routes

Step 5: Create Dynamic Routes with Variables

Flask allows you to create dynamic routes that capture values from the URL. This is useful for things like displaying user profiles or blog posts.

Modify app.py to create a dynamic route:

@app.route("/user/<username>")
def user_profile(username):
    return f"Hello, {username}!"

6. HTTP Methods and Routes

By default, Flask routes respond to GET requests. However, you can specify different HTTP methods like POST, PUT, or DELETE.

Step 6: Define Routes for POST Requests

Let’s modify the app.py file to include a POST route:

from flask import request

@app.route("/submit", methods=["POST"])
def submit():
    name = request.form.get("name")
    return f"Form submitted by {name}"

7. Using URL Variables in Templates

Flask allows you to pass variables to templates, which makes routing even more dynamic.

Step 7: Rendering Dynamic Content

Let’s render the dynamic route data in an HTML template. Create a templates/ folder and add an index.html file:

<!DOCTYPE html>
<html>
<head>
    <title>User Profile</title>
</head>
<body>
    <h1>Welcome {{ username }}!</h1>
</body>
</html>

Update app.py to use render_template and pass the username variable:

from flask import render_template

@app.route("/user/<username>")
def user_profile(username):
    return render_template("index.html", username=username)

Conclusion

In this guide, you’ve learned how to:

✅ Set up routing in Flask
✅ Create static and dynamic routes
✅ Handle different HTTP methods
✅ Pass variables to templates

Flask routing is a powerful tool that enables you to build dynamic web applications by mapping different URLs to Python functions. Now you’re ready to create more complex routes and interactive web applications using Flask! 🚀

PYTHON FLASK