Warning

tri.form is end of life. It has been merged into iommi.

iommi is backwards incompatible but the porting effort should be fairly mild, the biggest changes are that show is now called include and plural is used consistently for containers (so field__foo is fields__foo in iommi).

tri.form

tri.form is alternative forms library for Django and Flask. It is inspired by, and comes from a frustration with, the standard Django forms.

Major features compared to Django forms:

  • Supports __ syntax for going across table/object boundaries, similar to how Django does with QuerySets.
  • Send in a callable that is late evaluated to determine if a field should be displayed (show). This is very handy for showing a slightly different form to administrators for example.
  • Easy configuration without writing entire classes that are only used in one place anyway.

Example

You can either create a subclass of Form

class UserForm(Form):
    name = Field.text()
    username = Field.text(is_valid=lambda form, field, parsed_data: parsed_data.startswith('demo_'))
    is_admin = Field.boolean(
        show=lambda form, field: form.request.user.is_staff, # show only for staff
        label_template='tweak_label_tag.html')

def edit_user_view(request, username):
    form = UserForm(request=request)

    user = User.objects.get(username=username)
    if form.is_valid() and request.method == 'POST':
        form.apply(user)
        user.save()
        return HttpRedirect('..')

    return render(
        template_name='edit_user.html',
        context_instance=RequestContext(request, {'form': form}))
<!-- edit_user.html -->
<form action="" method="post">{% csrf_token %}
  <div>
    <table>
      {{ form }}
    </table>
  </div>
  <input type="submit" value="Save" />
</form>

or just instantiate a Form with a Field list and use it directly:

def edit_user_view(request, username):
    form = Form(fields=[
        Field.text(
            name='name',
            is_valid=lambda form, field, parsed_data: parsed_data.startswith('demo_')),
        Field.text(name='username'),
        Field.boolean(
            name='is_admin',
            show=lambda form, field: form.request.user.is_staff, # show only for staff
            label_template='tweak_label_tag.html',)])

    # rest of view function...

You can also generate forms from Django models automatically (but still change the behavior!). The above example is equivalent to:

def edit_user_view(request, username):
    form = Form.from_model(
        request.POST,
        User,
        # the field 'name' is generated automatically and we are fine with the defaults
        username__is_valid=lambda form, field, parsed_data: parsed_data.startswith('demo_'),
        is_admin__label_template='tweak_label_tag.html',
        is_admin__show=lambda form, field: form.request.user.is_staff) # show only for staff

    # rest of view function...

or even better: use tri.form.views.create_or_edit_object:

def edit_user_view(request, username):
    return create_or_edit_object(
        request,
        model=User,
        is_create=False,
        instance=User.objects.get(username=username),

        form__username__is_valid=lambda form, field, parsed_data: parsed_data.startswith('demo_'),
        form__is_admin__label_template='tweak_label_tag.html',
        form__is_admin__show=lambda form, field: form.request.user.is_staff) # show only for staff
    # no html template! tri.form has a nice default for you :P

tri.form pre-packages sets of defaults for common field types as ‘shortcuts’. Some examples include Field.boolean, Field.integer and Field.choice. The full list of shortcuts can be found in the API documentation for Field.

Running tests

You need tox installed then just make test.

License

BSD

Indices and tables