how I check in flask that field from form was filled by user

Question

I don't know how to check if user fill field in form in flask.

I have this form

<form method="POST" class="form-horizontal">
   <input type="text" name="name" value="{{ name }}">
   <input type="submit" class="btn" value="Add"/>
</form>

then I want check value in field and process it.

if request.method == 'POST':
    name = request.form['name']
    if name is None:  // this doesn't work
        # do something
    if name == string.empty: // this also doesn't work
        # do something

Please could you give me some advise. Thanks

Answer 1

I see you could have two problems here, the first one is that you not specify an action attribute in your form, so first fill it with the url that will handle your form, the second is that you are checking for None when an unfilled field is an empty string so you can use:

 name = request.form['name']
 if name == '':
      # do something

Alternatively if you want to fill the field with a default value when it not exists you can use get dict method as:

name = request.form.get('name', None)
if name is None:
     # do something

As other alternative you can use:

if not name:
    # do something

cause '' evaluate to False in a boolean expression.

Answer 2

Try this:

if request.method == "POST":
     ID = request.form['ID']
           if not ID=="":
               #do stuff`