Flask-WTF form populating integer fields and radio fields

Question

I'm trying to populate a full form under the condition that one of the field says "MATH& 142". this appears to work for some fields and not others.

Here is the code:

def formFill():
    @app.route('/formFill', methods=['GET', 'POST'])
    form = cifForm()
    if form.courseNum.data == 'MATH& 142':
        form.courseTitle.data = 'Precalculus II : Trigonometry' 
        form.publishInCollegeCatalog.data = True #NOT WORKING - Radio Field
        form.numCredit.data = int(5)  #NOT WORKING - Integer Field

class cifForm(Form):
    courseTitle = StringField('Course Title')
    publishInCollegeCatalog = RadioField('Publish in college catalog?', choices=[(True,'Yes'),(False,'No')], ) 
    numCredit = IntegerField('Credits')
    submit = SubmitField('Submit')

I have tried to print out some of the values on submit and noticed something interesting about the types

@app.route('/formFill', methods=['GET', 'POST'])
def formFill():
     form = cifForm()
    if form.courseNum.data == 'MATH& 142':
        form.courseTitle.data = 'Precalculus II : Trigonometry' 
        form.publishInCollegeCatalog.data = True# NOT WORKING
        print form.numCredit.data
        print type(form.numCredit.data)
        print form.creditIsVariable.data
        print type(form.numCredit.data)

console:

5
<type 'int'>
False
<type 'int'>

I also printed when I set them programmatically:

@app.route('/formFill', methods=['GET', 'POST'])
def formFill():
    form = cifForm()
    if form.courseNum.data == 'MATH& 142':
        form.courseTitle.data = 'Precalculus II : Trigonometry' 
        form.publishInCollegeCatalog.data = True# NOT WORKING
        form.numCredit.data = int(5) 
        print form.numCredit.data
        print type(form.numCredit.data)
        form.creditIsVariable.data = bool(False) #: NOT WORKING
        print form.creditIsVariable.data
        print type(form.numCredit.data)

console:

5
<type 'int'>
False
<type 'int'>

The output is identical, the variable assignments work, but I don't see these values in the rendered form.

Answer 1

I have tried to recreate your problem, but I am just not seeing it. You might however find my results working with RadioField interesting and I can at least point you towards a working solution.

This is your problem line:

form.publishInCollegeCatalog.data = True# NOT WORKING

The simple fix here is to simply do something like this:

form.publishInCollegeCatalog.data = str(True)# WORKING

You are conflating True with 'True':

Working Example:

from collections import namedtuple
from wtforms.validators import Required
from wtforms import Form
from wtforms import RadioField

from webob.multidict import MultiDict

class SimpleForm(Form):
    example = RadioField('Label',
            choices=[(True,'Truthy'),(False,'Falsey')])

# when this data is processed True is coerced to its
# string representation 'True'
data = {'example': True}

form = SimpleForm(data=MultiDict(data))

# checking form.data here yields - {'example': u'True'}    

# This prints the radio markup using the value `True`
print form.example

form.example.data = True

# This prints the radio using the value True
print form.example

What do they Render?

First print:

Second Print:

Explanation:

The RadioField renders a string representation of the value part of the choice. This is right in line with the HTML specification. Treated here.

value = string

Gives the default value of the input element.

The value part of the spec is treated as a string to support a wide range of values. WTForms has no choice but to treat this type as a string when it does its processing step. Its the least common denominator.

But what about my ints?

Once again this is not a problem that I am able to recreate. Every single IntegerField I create behaves exactly the same way. If you follow the example below your results should be the same.

class SimpleForm(Form):
    my_int = IntegerField()

data = {'my_int': int(5)}

form = SimpleForm(data=MultiDict(data))

print form.my_int

form.my_int.data = int(6)

print form.my_int

printing out

<input id="my_int" name="my_int" type="text" value="5">
<input id="my_int" name="my_int" type="text" value="6">

which is what one would expect.

Answer 2

You could try using:

form.numCredit.data = int(5) # This is defined as integer in your form
form.creditIsVariable.data = bool(False) # and so on

wtforms expects values in the proper datatype