Flask routing parameter with wrong value

Question

I am using flask and wtforms. When a user clicks a submit button for the form, I want to pop up a message saying that the submission succeeded. For that I have a parameter for my flask route with a default value of False. When the user submits, I want it to be true, so when it re-renders the page, it knows to show the user the extra bit saying "Success". However the parameter always seems to be false. My python looks like,

@app.route('/myPage', methods=['GET', 'POST'])
def myPage(success=False):
    print success

    form = MyForm()
    if form.validate_on_submit():
        print "did validate"
        return redirect(url_for('myPage', success=True))

    return render_template('/MyPage.html', form=form, success=success)

And my html looks like,

...
{% if success %}
    <div class="alert alert-success alert-dismissable">
        <button type="button" class="close" data-dismiss="alert" aria-hidden="true">×</button> User added
    </div>
{% endif %}
...
<form method="POST" action="{{ url_for('register', success=True) }}">
...

In both my python and html redirects, I try setting success to be true, but no combination of those seem to work. When I "print success", it always says that it is false. Any ideas?

Avish · Accepted Answer · 2016-04-12 07:50:13Z

1

Flask binds method parameters to route arguments if they a part of the route. See documentation.

Try:

@app.route('/mypage/<int:success>', defaults={'success': 0})
def my_page(success):
   ...

This would cause url_for to build a URL like /mypage/1 or /mypage/True, which is probably not what you want.

If you want to use a querystring parameter, you should manually get it from the request:

@app.route('/mypage/')
def my_page():
  success = request.args.get('success', False)
  ...

url_for('my_page', success=True) would now generate something like /mypage/?success=True because:

Variable arguments that are unknown to the target endpoint are appended to the generated URL as query arguments.

(from the url_for docs)

edited Apr 12, 2016 at 7:50

answered Apr 12, 2016 at 7:44

Avish

4,64622 silver badges28 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Joe Johnson Over a year ago

Thank you very much, I used the "success = request.args.get('success', False)" method, and it works like a charm.

Collectives™ on Stack Overflow

Flask routing parameter with wrong value

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related