Error message display in templates in Flask - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to display an error message in a Flask template using Jinja2 syntax.

Flask

<p>{{ [1] }}</p>

Drag options to blanks, or click blank then click option'

Aerror_message

Bmessage

Cerror

Dflash

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable name not passed from the Flask view.

Trying to call a function inside the template instead of displaying a variable.

The variable error is commonly used to pass error messages to the template in Flask. Using {{ error }} displays the error message.

2fill in blank

medium

Complete the Flask view code to pass an error message to the template named 'form.html'.

Flask

from flask import render_template

@app.route('/submit', methods=['POST'])
def submit():
    error = 'Invalid input'
    return render_template('form.html', [1]=error)

Drag options to blanks, or click blank then click option'

Aerror

Bmessage

Cflash

Dmsg

Attempts:

3 left

💡 Hint

Common Mistakes

Passing a different key name than the one used in the template.

Forgetting to pass the error variable to the template.

The key error is used to pass the error message variable error to the template. This allows the template to access it as {{ error }}.

3fill in blank

hard

Fix the error in the template code to correctly display the error message only if it exists.

Flask

{% if [1] %}
  <div class="error">{{ error }}</div>
{% endif %}

Drag options to blanks, or click blank then click option'

Aerror_message

Berror

Cmessage

Dflash

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable name that is not defined in the template context.

Using incorrect Jinja2 syntax for the if statement.

The condition should check if the variable error exists and is truthy before displaying it. Using {% if error %} is correct.

4fill in blank

hard

Fill both blanks to create a Flask template snippet that loops over multiple error messages stored in a list called 'errors'.

Flask

{% for [1] in [2] %}
  <p class="error">{{ [1] }}</p>
{% endfor %}

Drag options to blanks, or click blank then click option'

Aerror

Berrors

Cmsg

Dmessages

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same name for both loop variable and list.

Using a variable name not passed from the Flask view.

The loop variable is error and the list is errors. This loops over each error message to display it.

5fill in blank

hard

Fill all three blanks to create a Flask view function that flashes an error message and redirects to the 'index' page.

Flask

from flask import flash, redirect, url_for

@app.route('/login', methods=['POST'])
def login():
    flash([1], category=[2])
    return redirect(url_for([3]))

Drag options to blanks, or click blank then click option'

A'Login failed'

B'error'

C'index'

D'success'

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around string literals.

Using wrong category names or route names.

The flash function sends the message 'Login failed' with category 'error'. The redirect goes to the index page.