Author: John Au-Yeung

Sometimes, we want to get the named parameters from a URL using Python Flask

In this article, we’ll look at how to get the named parameters from a URL using Python Flask.

How to get the named parameters from a URL using Python Flask?

To get the named parameters from a URL using Python Flask, we can use the request.args property.

For instance, we write

from flask import request

@app.route('/login')
def login():
    username = request.args.get('username')
    password = request.args.get('password')

to call request.args.get with the keys of the query parameters we want to get in our view function.

Conclusion

To get the named parameters from a URL using Python Flask, we can use the request.args property.

Sometimes, we want to get a variable from the URL in a Python Flask route.

In this article, we’ll look at how to get a variable from the URL in a Python Flask route.

How to get a variable from the URL in a Python Flask route?

To get a variable from the URL in a Python Flask route, we can get it from the view function parameters.

For instance, we write

@app.route('/landingpage/<id>')
def landing_page(id):
    #...

to get the id URL parameter from the id parameter in the landing_page function.

We can use the url_for function to generate URLs for pages by writing

url_for('landing_page', id='A')

where the first argument is the view name.

Conclusion

To get a variable from the URL in a Python Flask route, we can get it from the view function parameters.

Sometimes, we want to add a prefix to all Python Flask routes

In this article, we’ll look at how to add a prefix to all Python Flask routes.

How to add a prefix to all Python Flask routes?

To add a prefix to all Python Flask routes, we can create a blueprint.

For instance, we write

bp = Blueprint('burritos', __name__,
                        template_folder='templates')

@bp.route("/")
def index_page():
  return "eat burritos"

@bp.route("/about")
def about_page():
  return "eat burritos"

to create the bp blueprint with the Blueprint class.

We call it with the burritos' string to set that as the blueprint name.

Then we create routes in the blueprint with the bp.route decorator.

Next, we register our blueprint with app.register_blueprint

app = Flask(__name__)
app.register_blueprint(bp, url_prefix='/abc/123')

We set the URL prefix by setting the url_prefix argument when registering.

Conclusion

To add a prefix to all Python Flask routes, we can create a blueprint.

Sometimes, we want to debug a Python Flask app.

In this article, we’ll look at how to debug a Python Flask app.

How to debug a Python Flask app?

To debug a Python Flask app, we set the FLASK_APP and FLASK_ENV environment variables before running the app.

To do this on Linux and Mac, we run

export FLASK_APP=myapp
export FLASK_ENV=development
flask run

to set the environment variables with export.

And then we run flask run to run the app.

On Windows, we replace export with set in the command prompt.

And in Windows PowerShell, we run

$env:FLASK_ENV = "development"

to set the environment variables with $env:.

Conclusion

To debug a Python Flask app, we set the FLASK_APP and FLASK_ENV environment variables before running the app.

Sometimes, we want to fix Python Flask view returning error "View function did not return a response"

In this article, we’ll look at how to fix Python Flask view returning error "View function did not return a response".

How to fix Python Flask view returning error "View function did not return a response"?

To fix Python Flask view returning error "View function did not return a response", we should return a response in our view.

For instance, we write

@app.route('/hello', methods=['GET', 'POST'])
def hello():
    return hello_world()

to return the value returned by hello_world as the response in the hello view function.

Conclusion

To fix Python Flask view returning error "View function did not return a response", we should return a response in our vie