CodeToLive

Flask Routing & Views

Routing is one of Flask's core features, allowing you to map URLs to Python functions that handle the requests.

Basic Routing


@app.route('/')
def home():
    return 'Home Page'

@app.route('/about')
def about():
    return 'About Page'

Variable Rules


@app.route('/user/<username>')
def show_user_profile(username):
    return f'User {username}'

@app.route('/post/<int:post_id>')
def show_post(post_id):
    return f'Post {post_id}'

HTTP Methods


@app.route('/login', methods=['GET', 'POST'])
def login():
    if request.method == 'POST':
        return do_the_login()
    else:
        return show_the_login_form()

URL Building


from flask import url_for

@app.route('/')
def index():
    return url_for('login', next='/')  # Outputs: /login?next=/

Redirects


from flask import redirect

@app.route('/old-page')
def old_page():
    return redirect(url_for('new_page'))

Error Handling


@app.errorhandler(404)
def page_not_found(error):
    return render_template('404.html'), 404

Blueprint Routing


from flask import Blueprint

auth = Blueprint('auth', __name__)

@auth.route('/login')
def login():
    return 'Login Page'

# Register blueprint in main app
app.register_blueprint(auth, url_prefix='/auth')

Best Practices

Next: Templates (Jinja2)