3.3 KiB

Raw Blame History

Horizon Forms

Horizon ships with some very useful base form classes, form fields, class-based views, and javascript helpers which streamline most of the common tasks related to form handling.

Form Classes

horizon.forms.base

Form Fields

horizon.forms.fields

Form Views

horizon.forms.views

Auth Forms

openstack_auth.forms

Forms Javascript

Switchable Fields

By marking fields with the "switchable" and "switched" classes along with defining a few data attributes you can programmatically hide, show, and rename fields in a form.

The triggers are fields using a select input widget, marked with the "switchable" class, and defining a "data-slug" attribute. When they are changed, any input with the "switched" class and defining a "data-switch-on" attribute which matches the select input's "data-slug" attribute will be evaluated for necessary changes. In simpler terms, if the "switched" target input's "switch-on" matches the "slug" of the "switchable" trigger input, it gets switched. Simple, right?

The "switched" inputs also need to define states. For each state in which the input should be shown, it should define a data attribute like the following: data-<slug>-<value>="<desired label>". When the switch event happens the value of the "switchable" field will be compared to the data attributes and the correct label will be applied to the field. If a corresponding label for that value is not found, the field will be hidden instead.

A simplified example is as follows:

source = forms.ChoiceField(
    label=_('Source'),
    choices=[
        ('cidr', _('CIDR')),
        ('sg', _('Security Group'))
    ],
    widget=forms.ThemableSelectWidget(attrs={
        'class': 'switchable',
        'data-slug': 'source'
    })
)

cidr = fields.IPField(
    label=_("CIDR"),
    required=False,
    widget=forms.TextInput(attrs={
        'class': 'switched',
        'data-switch-on': 'source',
        'data-source-cidr': _('CIDR')
    })
)

security_group = forms.ChoiceField(
    label=_('Security Group'),
    required=False,
    widget=forms.ThemableSelectWidget(attrs={
        'class': 'switched',
        'data-switch-on': 'source',
        'data-source-sg': _('Security Group')
    })
)

That code would create the "switchable" control field source, and the two "switched" fields cidr and security group which are hidden or shown depending on the value of source.

Note

A field can only safely define one slug in its "switch-on" attribute. While switching on multiple fields is possible, the behavior is very hard to predict due to the events being fired from the various switchable fields in order. You generally end up just having it hidden most of the time by accident, so it's not recommended. Instead just add a second field to the form and control the two independently, then merge their results in the form's clean or handle methods at the end.

3.3 KiB Raw Blame History