.. _extensions: Extensions ========== .. module:: wtforms.ext WTForms ships with a number of extensions that make it easier to work with other frameworks and libraries, such as Django. Django ------ .. module:: wtforms.ext.django This extension provides templatetags to make it easier to work with Django templates and WTForms' html attribute rendering. It also provides a generator for automatically creating forms based on Django ORM models. Templatetags ~~~~~~~~~~~~ .. module:: wtforms.ext.django.templatetags.wtforms Django templates does not allow arbitrarily calling functions with parameters, making it impossible to use the html attribute rendering feature of WTForms. To alleviate this, we provide a templatetag. Adding :mod:`wtforms.ext.django` to your INSTALLED_APPS will make the wtforms template library available to your application. With this you can pass extra attributes to form fields similar to the usage in jinja: .. code-block:: django {% load wtforms %} {% form_field form.username class="big_text" onclick="do_something()" %} **Note** By default, using the `{{ form.field }}` syntax in django models will be auto-escaped. To avoid this happening, use Django's `{% autoescape off %}` block tag or use WTForms' `form_field` template tag. Model forms ~~~~~~~~~~~ .. module:: wtforms.ext.django.orm .. autofunction:: model_form(model, base_class=Form, include_pk=False) :func:`model_form` attempts to glean as much metadata as possible from inspecting the model's fields, and will even attempt to guess at what validation might be wanted based on the field type. For example, converting an `EmailField` will result in a :class:`~wtforms.fields.TextField` with the :func:`~wtforms.validators.email` validator on it. if the `blank` property is set on a model field, the resulting form field will have the :func:`~wtforms.validators.optional` validator set. Just like any other Form, forms created by ModelForm can be extended via inheritance:: UserFormBase = model_form(User) class UserForm(UserFormBase): new_pass = PasswordField('', [validators.optional(), validators.equal_to('confirm_pass')]) confirm_pass = PasswordField() When combined with :meth:`form iteration `, model_form is a handy way to generate dynamic CRUD forms which update with added fields to the model. One must be careful though, as it's possible the generated form fields won't be as strict with validation as a hand-written form might be. ORM-backed fields ~~~~~~~~~~~~~~~~~ .. module:: wtforms.ext.django.fields While linking data to most fields is fairly easy, making drop-down select lists using django ORM data can be quite repetetive. To this end, we have added some helpful tools to use the django ORM along with wtforms .. autoclass:: QuerySetSelectField(default field args, queryset=None, label_attr='', allow_blank=False, blank_text=u'') .. code-block:: python class ArticleEdit(Form): title = TextField() column = QuerySetSelectField(label_attr='title', allow_blank=True) category = QuerySetSelectField(queryset=Category.objects.all()) def edit_article(request, id): article = Article.objects.get(pk=id) form = ArticleEdit(obj=article) form.column.queryset = Column.objects.filter(author=request.user) As shown in the above example, the queryset can be set dynamically in the view if needed instead of at form construction time, allowing the select field to consist of choices only relevant to the user. .. autoclass:: ModelSelectField(default field args, model=None, label_attr='', allow_blank=False, blank_text=u'') SQLAlchemy ---------- .. module:: wtforms.ext.sqlalchemy This extension provides SelectField integration with SQLAlchemy ORM models, similar to those in the Django extension. ORM-backed fields ~~~~~~~~~~~~~~~~~ .. module:: wtforms.ext.sqlalchemy.fields These fields are provided to make it easier to use data from ORM objects in your forms. Due to the complication of dealing with multiple-primary-keyed tables, currently it is only possible to use these fields with simple integer primary keyed ORM models. .. code-block:: python def enabled_categories(): return Category.query.filter_by(enabled=True) class BlogPostEdit(Form): title = TextField() blog = QuerySelectField() category = QuerySelectField(query_factory=enabled_categories, allow_blank=True) def edit_blog_post(request, id): post = Post.query.get(id) form = ArticleEdit(obj=post) form.blog.query = Blog.query.filter(Blog.author == request.user).order_by(Blog.name) .. autoclass:: QuerySelectField(default field args, query_factory=None, pk_attr='id', label_attr='', allow_blank=False, blank_text=u'') .. autoclass:: ModelSelectField(default field args, model=None, pk_attr='id', label_attr='', allow_blank=False, blank_text=u'')