How to display html content through flask messages?

Question

I understand that flash() takes only string and displays that in the redirected page. I m trying to send html through flash

message = "<h1>Voila! Platform is ready to used</h1>" flash(message) return render_template('output.html') 

output.html

<div class="flashes">   {% for message in get_flashed_messages()%}     {{ message }}   {% endfor %} </div> 

But it is displaying as string <h1>Voila! Platform is ready to used</h1> is there any way to overcome this.

Answer 1

Where possible, a secure approach is to wrap your string in a Markup object before passing it to the template:

Python code:

from flask import Markup  message = Markup("<h1>Voila! Platform is ready to used</h1>") flash(message) return render_template('output.html') 

Jinja2 Template:

<div class="flashes">   {% for message in get_flashed_messages() %}     {{ message }}   {% endfor %} </div> 

Using {{message|safe}} will work, but also opens up the door for an attacker to inject malicious HTML or Javascript into your page, also known an an XSS attack. More info here if you're interested.