Flask – how to call python function with parameters in button?

I am working on a notification system on my website. I decided to make a model in the database for them. I also made a function in views.py that takes an argument of a user that is receiving a notification and the type of notification. Here is the code:

@views.route('/send_notification',methods = ['GET','POST'])
@login_required
def send_notification(user, type):

    reciever = User.query.filter_by(username = user).first()

    if type == 'family-invitation':
        family = Family.query.filter_by(id = current_user.family_id).first()
        description = "invites you to their family!"
        new_notification = Notification(sender = current_user.username, sender_prof_img = family.prof_img, user_id = reciever.id, description = description)
        db.session.add(new_notification)
        db.session.commit()
        flash("Invitation to family has been sent!", category="success")

    return True

Now I want to be able to send the user a notification when someone invites them. I was thinking about calling the python function when someone presses the button but I don’t know how to code it.

I came up with something like this but it doesn’t work:

<button
      onclick="window.location.href = '{{ url_for('views.send_notification(profileUser.username, 'family-invitation')') }}';"
    >
      Invite to family
    </button>

Answer

url_for() in Flask Jinja templates does not work like that. It forms a URL to a specific resource, which means you can not pass Python code as a parameter. The option that comes to my mind first is to use URL parameters for passing data to your route function.

@views.route('/send_notification/<user>/<type>',methods = ['GET','POST'])
@login_required
def send_notification(user, type):

    reciever = User.query.filter_by(username = user).first()

    if type == 'family-invitation':
        family = Family.query.filter_by(id = current_user.family_id).first()
        description = "invites you to their family!"
        new_notification = Notification(sender = current_user.username,                     
    sender_prof_img = family.prof_img, user_id = reciever.id, description = description)
    db.session.add(new_notification)
    db.session.commit()
    flash("Invitation to family has been sent!", category="success")

return True

So that your HTML would look like that:

<button
  onclick="btnOnClick(profileUser.username, 'family-invitation');"
    >
  Invite to family
</button>
<script>
    function btnOnClick(username, notificationType) {
    window.location = `/send_notification/${username}/${notificationType}`;
}
</script>