Mojo Form Helpers¶

Mojo offers convenience functions to make handling forms with the database easier. At it’s core these functions are wrappers arounf basic wtForms functionality to make Form management easier.

class Mojo.Forms.MojoFormHelper.Form(formdata=None, obj=None, prefix='', locale_code='en_US', **kwargs)¶

A wrapper around the standard wtForms Form object that integrates with tornado. Modified slightly for compatibility with Mojo models - you can pre-populate a form and populate a model using this Form class instead of the standard wtForms Form.

Example:

class SigninForm(Form):
    email = EmailField('email')
    password = PasswordField('password')

class SigninHandler(RequestHandler):
    def get(self):
        form = SigninForm(self.request.arguments, locale_code=self.locale.code)

classmethod populate_from_model(klass, model, ignore=[])¶

Populates a form from a model, if you want to ignore some fields, use the ignore list (of strings) to set which fields not to be iterated over.

populate_model_from_data(modelObj, ignore=[])¶

Will populate a model from the data provided by a form. Use the ignore list (must all be strings) to ignore data keys passed back by your form.

Mojo.Forms.MojoFormHelper.model_as_form(model, initObj=None, ignore=[], override={})¶

Will take a model (non instantiated) object and produce a WTForm Form instance, this function only works one-way.

model_as_form can take three parameters:

• initObj - If you want to inittialise the form with data, pass it an instance of the model in question and it will do it’s best to instantiate it
• ignore - If you want to exclude a list of fields from the automated conversion you can specify them as a list of strings corresponding to the name of the field in your model
• override - To specify a custom wtForm field type, pass these as a dictionary of {"field name":FieldType,}

note: The override function takes either classes or instantiated objects, so if you want to pass through custom validators

as part of the override, simply specify them in the override as if you would in a standard Form definition.

Usage:

from Mojo.Forms.MojoFormHelper import model_as_form

# Let's get some data from our imaginary blog app
posts = yield gen.Task(BlogPost.find_async, {'published':True}, sort=[('date_published',1)])
a_post = posts[0]

# Define a custom override set, the first is a base class,
# the second is an instance with my custom validators:

overrides = {'post_body': TextAreaField,
             'post_intro': TextAreaField('Your intro text', [validators.required(),
                                                             validators.length(max=10)]}

# Create the form - we will ignore tags and
# comments (these are Lists, and not implemented),
# and override with our custom fields (StringFields are by
# default TextFields, but we want TextAreas):

thisForm = model_as_form(BlogPost, initObj=a_post, ignore=['tags', 'comments'], override=overrides)

# ...Now do something with the form

The system will automatically transform required model fields to required Form fields, no other validation checks are passed through yet.

For the ‘friendly name’ o your form field, Mojo will use the friendly Mojo Model Form parameter, if none is present, Mojo will use the name of the Modle Field.