Pylons FormEncode with an array of form elements

Question

I have a Pylons app and am using FormEncode and HtmlFill to handle my forms. I have an array of text fields in my template (Mako)

  <tr>
    <td>Yardage</td>
    <td>${h.text('yardage[]', maxlength=3, size=3)}</td>
    <td>${h.text('yardage[]', maxlength=3, size=3)}</td>
    <td>${h.text('yardage[]', maxlength=3, size=3)}</td>
    <td>${h.text('yardage[]', maxlength=3, size=3)}</td>
    <td>${h.text('yardage[]', maxlength=3, size=3)}</td>
    <td>${h.text('yardage[]', maxlength=3, size=3)}</td>
    <td>${h.text('yardage[]', maxlength=3, size=3)}</td>
    <td>${h.text('yardage[]', maxlength=3, size=3)}</td>
    <td>${h.text('yardage[]', maxlength=3, size=3)}</td>
  </tr>

However, I can't seem to figure out how to validate these fields. Here is the relevant entry from my Schema

yardage = formencode.ForEach(formencode.validators.Int())

I'm trying to validate that each of these fields is an Int. However, no validation occurs for these fields.

UPDATE As requested here is the code for the action of this controller. I know it was working as I can validate other form fields.

    def submit(self):
        schema = CourseForm()
        try:
            c.form_result = schema.to_python(dict(request.params))
        except formencode.Invalid, error:
            c.form_result = error.value
            c.form_errors = error.error_dict or {}
            c.heading = 'Add a course'
            html = render('/derived/course/add.html')
            return htmlfill.render(
                html,
                defaults = c.form_result,
                errors = c.form_errors 
                )
        else:
            h.redirect_to(controler='course', action='view')

UPDATE It was suggested on IRC that I change the name of the elements from yardage[] to yardage No result. They should all be ints but putting in f into one of the elements doesn't cause it to be invalid. As I said before, I am able to validate other form fields. Below is my entire schema.

import formencode

class CourseForm(formencode.Schema):
    allow_extra_fields = True
    filter_extra_fields = True
    name = formencode.validators.NotEmpty(messages={'empty': 'Name must not be empty'})
    par = formencode.ForEach(formencode.validators.Int())
    yardage = formencode.ForEach(formencode.validators.Int())

Answer 1

Turns out what I wanted to do wasn't quite right.

Template:

 <tr>
    <td>Yardage</td>
    % for hole in range(9):
    <td>${h.text('hole-%s.yardage'%(hole), maxlength=3, size=3)}</td>
    % endfor
 </tr>

(Should have made it in a loop to begin with.) You'll notice that the name of the first element will become hole-1.yardage. I will then use FormEncode.variabledecode to turn this into a dictionary. This is done in the

Schema:

import formencode

class HoleSchema(formencode.Schema):
    allow_extra_fields = False
    yardage = formencode.validators.Int(not_empty=True)
    par = formencode.validators.Int(not_empty=True)

class CourseForm(formencode.Schema):
    allow_extra_fields = True
    filter_extra_fields = True
    name = formencode.validators.NotEmpty(messages={'empty': 'Name must not be empty'})
    hole = formencode.ForEach(HoleSchema())

The HoleSchema will validate that hole-#.par and hole-#.yardage are both ints and are not empty. formencode.ForEach allows me to apply HoleSchema to the dictionary that I get from passing variable_decode=True to the @validate decorator.

Here is the submit action from my

Controller:

    @validate(schema=CourseForm(), form='add', post_only=False, on_get=True, 
              auto_error_formatter=custom_formatter,
              variable_decode=True)
    def submit(self):
        # Do whatever here.
        return 'Submitted!'

Using the @validate decorator allows for a much cleaner way to validate and fill in the forms. The variable_decode=True is very important or the dictionary will not be properly created.

Answer 2

I wrote an article just a few days ago, also touching this matter.

Answer 3

c.form_result = schema.to_python(request.params) - (without dict) it seems to works fine