Flashing Messages in Flask: Providing Feedback to Users

As developers, we all want to create GUI applications that give users a smooth and easy experience. One way to make the user interface more informative and user-friendly is by using feedback messages.

In this article, well explore how to create feedback messages in Flask using the flash method, which allows us to send a message to the user for a brief period.to Flashing Messages

First, lets define what flashing messages really are. In a Flask application, a flashing message is a message thats only available one time, usually displayed on a template after being flashed.

The message is saved until it is retrieved, after which it is discarded, which is great for providing immediate feedback to the user. These messages are often used for successful user input or to alert the user of errors.

Flask flash method overview

The flash method is a built-in function of Flask that allows us to send messages with a category. Flask will save these messages for a short period and we can use these messages in the next request that the user makes, such as a page redirection.

The flash method accepts two parameters: the message and the category. The category parameter is used to group messages to allow your code to differentiate between messages of different types.

Using get_flashed_messages() to extract messages and display on template

After flashing a message, we can retrieve it from the session and display it to the user. To do that, we can use the get_flashed_messages() function, which retrieves all of the flashed messages and removes them from the session.

We can then send this array to a template to display the messages to the user.

Coding the Flask Application File

Now that we have a basic understanding of how to use Flask flashing messages, lets create a Flask application. In this example, well create a form that allows a user to enter their information, then a success page that displays the users input.

First, well start by importing Flask and create the app object. “`

from flask import Flask, render_template, request, redirect, flash

app = Flask(__name__)

“`

Next, well create two routes, one for the form and another for the success page.

“`

@app.route(‘/’)

def form_page():

return render_template(‘form.html’)`

@app.route(‘/success’, methods=[‘POST’])

def success_page():

if request.method == ‘POST’:

name = request.form[‘name’]

email = request.form[’email’]

flash(‘Form submitted successfully!’, ‘success’)

return redirect(‘/success’)

return render_template(‘form.html’)`

“`

Creating the Form.html and Success.html Templates

Now that we have created our Flask routes, its time to move onto creating the templates. In this example, well create two templates, one to display the form and another to display the successful submission message.

Form.html:

“`

{% extends ‘base.html’ %}

{% block content %}

Submit

{% with messages = get_flashed_messages() %}

{% if messages %}

{% for message in messages %}

• {{ message }}

{% endfor %}

{% endif %}

{% endwith %}

{% endblock %}

“`

Success.html:

“`

{% extends ‘base.html’ %}

{% block content %}

Thank you for your submission!

{% with messages = get_flashed_messages() %}

{% if messages %}

{% for message in messages %}

• {{ message }}

{% endfor %}

{% endif %}

{% endwith %}

{% endblock %}

“`

Implementing the Flashing Message

Now that we have the templates ready, we want to display a message when the user successfully submits the form. To do that, well use the flash() method to add the message to the session.

“`

flash(‘Form submitted successfully!’, ‘success’)

“`

We also want to use the get_flashed_messages() method in our templates to extract the message and display it. ““

{% with messages = get_flashed_messages() %}

{% if messages %}

{% for message in messages %}

• {{ message }}

{% endfor %}

{% endif %}

{% endwith %}

““

Conclusion

Using flashes in Flask application is an easy way to provide users with feedback. This not only makes the user experience more pleasant and intuitive, but it also makes the app more reliable.

In this article, we have seen a simple example of how to create flash messages in a Flask application. As you continue to build more advanced Flask apps, be sure to make use of this powerful feature to create robust and informative user interfaces.

To summarize, flashing messages in Flask is an effective way for developers to provide immediate feedback to users. The Flask flash method enables developers to send a message with a category, which can be used to group messages and allow the code to differentiate between messages of different types.

The get_flashed_messages() function is used to retrieve flashed messages and display them on the template. In this article, we have seen how to create Flask applications with flashing messages by coding the Flask app file, creating templates, and implementing the flashing message.

By using flashes in Flask applications, we can improve the user experience, which not only makes the app more reliable but also creates a more pleasant and intuitive user interface.