WTForms Documentation

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# class Meta

the class Meta paradigm allows WTForms features to be customized, and even new behaviors to be introduced. It also supplies a place where configuration for any complementary modules can be done.

Typical usage looks something like:

    class MyForm(Form):
        class Meta:
            csrf = True
            locales = ('en_US', 'en')

        name = TextField(...)
        # and so on...

For the majority of users, using a class Meta is mostly going to be done for customizing options used by the default behaviors, however for completeness the entire API of the Meta interface is shown here.

class `wtforms.meta.` `DefaultMeta`

  This is the default Meta class which defines all the default values and therefore also the ‘API’ of the class Meta interface.

  Configuration

  `csrf` = False

    Setting `csrf` to True will enable CSRF for the form. The value can also be overridden per-instance via instantiation-time customization (for example, if csrf needs to be turned off only in a special case)

        form = MyForm(request.form, meta={'csrf': False})

  `csrf_class` = None

    If set, this is a class which is used to implement CSRF protection. Read the CSRF Documentation to get more information on how to use.

  `csrf_field_name` = 'csrf_token'

    The name of the automatically added CSRF token field.

  `locales` = False

    Setting to a sequence of strings specifies the priority order of locales to try to find translations for built-in messages of WTForms. If the value False, then strings are not translated (the translations provider is a dummy provider)

  `cache_translations` = True

    If True (the default) then cache translation objects. The default cache is done at class-level so it’s shared with all class Meta.

  Advanced Customization

  Usually, you do not need to override these methods, as they provide core behaviors of WTForms.

  `build_csrf`(form)

    Build a CSRF implementation. This is called once per form instance.

    The default implementation builds the class referenced to by `csrf_class` with zero arguments. If csrf_class is `None`, will instead use the default implementation `wtforms.csrf.session.SessionCSRF`.

    Parameters

      form – The form.

    Returns

      A CSRF implementation.

  `get_translations`(form)

    Override in subclasses to provide alternate translations factory. See the i18n documentation for more.

    Parameters

      form – The form.

    Returns

      An object that provides gettext() and ngettext() methods.

  `bind_field`(form, unbound_field, options)

    bind_field allows potential customization of how fields are bound.

    The default implementation simply passes the options to `UnboundField.bind()`.

    Parameters

      - form – The form.

      - unbound_field – The unbound field.

      - options – A dictionary of options which are typically passed to the field.

    Returns

      A bound field

  `wrap_formdata`(form, formdata)

    wrap_formdata allows doing custom wrappers of WTForms formdata.

    The default implementation detects webob-style multidicts and wraps them, otherwise passes formdata back un-changed.

    Parameters

      - form – The form.

      - formdata – Form data.

    Returns

      A form-input wrapper compatible with WTForms.

  `render_field`(field, render_kw)

    render_field allows customization of how widget rendering is done.

    The default implementation calls `field.widget(field, **render_kw)`