Package

djarg

class djarg.qset(objects, *, qset=None, model=None, pk='pk', select_for_update=None)

Lazily coerces a value into a queryset. Can be used inside of python-args decorators.

Can coerce the following types:

1. Queryset: Returns the queryset.

2. None: Returns an empty queryset.

3. <primary key>: Returns queryset with single element.

4. Model: Returns queryset with single model.

5. List[<primary key>]: Returns queryset with all elements.

6. List[Model]: Returns queryset with all models.

Parameters

• objects (str) – The argument name to be evaluated.

• qset (QuerySet) – The queryset to use for the initial queryset when a list of values is provided.

• model (Model) – The model to use for the queryset when a list of values is provided.

• select_for_update (List[str], default=None) – Adds a select_for_update using the provided arguments. Does not perform select_for_update when running in partial mode. If a list is provided, the list is used as the of argument for select_for_update. If a dictionary is provided, the values are passed as kwargs to select_for_update. If True is provided, no arguments are passed to select_for_update.

Examples

Using djarg.qset with python-args arg.default decorator:

import arg
import djarg

@arg.defaults(
    profiles=djarg.qset('profiles', model=Profile).select_related('address')
)
def fetch_zip_codes(profiles):
    return [profile.address.zip for profile in profiles]

# All of these invocations can be used
fetch_zip_codes(Profile.objects.all())
# A single model object
fetch_zip_codes(single_profile_object)
# A single PK
fetch_zip_codes(1)
# Lists of PKs or model objects
fetch_zip_codes([2, 3])
fetch_zip_codes([Profile(...), Profile(...)])

djarg.forms

class djarg.forms.Field(*args, **kwargs)

A lazy python-args adapter to lazily load a Django form field.

When declaring a form, a form field can be wrapped in the Field object so that all attributes can be lazily loaded.

Example

This is an example of lazily loading a form field so that we can dynamically fill out help text:

class MyForm(forms.Form):
    field = Field(CharField, help_text=args.func(get_help_text))

djarg.forms.adapt(form, func, default_args=None, clean=True)

Adapt a form to an python-args func, ensuring the form validation behaves seamlessly with function validation.

Evaluate any djarg.form.Field classes that are fields of the form.

Parameters

• form (django.forms.Form) – The Django form being adapted.

• func (function) – A function decorated with python-args decorators.

• default_args (dict, default=None) – A dictionary of any other default arguments that are used when calling the python-args function.

• clean (bool, default=True) – Adapt the clean method to the validators of the func

djarg.forms.get_field_validator(func, field_label)

Given a field label and function, generate a form field validator from the function. It is assumed that the function is wrapped with python-args.

Django form fields need to raise ValidationErrors in order for errors to bubble up properly. This function wraps any validators for the field and re-raises ValidationErrors

djarg.forms.get_form_clean(func, form, default_args=None)

Returns a form clean method for the form, using any validators present on the python-args wrapped func.

djarg.views

class djarg.views.FormView(**kwargs)

A generic form view that runs a binded python-args function.

Instatiate the FormView similar to a regular django FormView, and also declare the func attribute to point to a python-args function.

The form of this view will automatically be adapted to use the validators of the function, and the form_valid method will run the function with the parameters from the form.

class djarg.views.MultipleObjectsMixin

Similar to Django’s SingleObjectMixin, but allows for pulling multile arguments through GET parameters.

Most of this code was directly adapted from

get_context_data(**kwargs)

Insert the single object into the context dict.

get_context_objects_name(objects)

Get the name to use for the object.

get_default_args()

Return any arguments that should be sent to the function and made available during lazy form field loading.

get_objects()

Return the objects the view is displaying. Require self.queryset and a pk argument in the GET query string. Subclasses can override this to return any object.

get_queryset()

Returns the queryset for multi-object views. If the queryset as been overridden to be a “lazy” function (e.g. from python-args), the function will be evaluated with request as a keyword argument and returned. Otherwise, it defaults to Django’s generic detail-view get_queryset() function.

class djarg.views.ObjectFormView(**kwargs)

A generic view for single objects that runs a binded python-args function.

Similar to FormView, the form of this view will automatically be adapted to use the validators of the function, and the form_valid method will run the function with the parameters from the form.

class djarg.views.ObjectWizardView(**kwargs)

A WizardView that operates on a single object.

class djarg.views.ObjectsFormView(**kwargs)

A generic view for multiple objects that runs a binded python-args function.

Similar to FormView, the form of this view will automatically be adapted to use the validators of the function, and the form_valid method will run the function with the parameters from the form.

class djarg.views.ObjectsWizardView(**kwargs)

A WizardView that operates on multiple objects.

class djarg.views.SessionObjectWizardView(**kwargs)

An ObjectWizardView with pre-configured SessionStorage backend.

class djarg.views.SessionObjectsWizardView(**kwargs)

An ObjectsWizardView with pre-configured SessionStorage backend.

class djarg.views.SessionWizardView(**kwargs)

A WizardView with pre-configured SessionStorage backend.

class djarg.views.SingleObjectMixin

get_default_args()

Return any arguments that should be sent to the function and made available during lazy form field loading.

get_queryset()

Returns the queryset for single-object views. If the queryset as been overridden to be a “lazy” function (e.g. from python-args), the function will be evaluated with request as a keyword argument and returned. Otherwise, it defaults to Django’s generic detail-view get_queryset() function.

class djarg.views.SuccessMessageMixin

Similar to Django’s SuccessMessageMixin, allows views to add a success message when successfully finished.

Users can override the success_message attribute or override the get_success_message(self, args, results) method. The latter takes the arguments provided to the main view func attribute and the results from running the view func.

class djarg.views.WizardView(**kwargs)

Adaptation of django-formtool’s wizard view.

Children of this class, such as SessionWizardView, can use lazy evaluation methods present in python-args.

done(*args, **kwargs)

This method must be overridden by a subclass to process to form data after processing all steps.

get_cleaned_data(*steps)

Gets cleaned data for all steps in order given.

If any steps don’t validate, return None

get_cleaned_data_for_step(step)

Get cleaned data for a specific step.

get_form(step=None, **kwargs)

Get a form for a specific step

get_form_list(until=None)

Overrides get_form_list() to dynamically evaluate arg.func() conditions. Allows conditional evaluation up to a specific step so that we avoid various infinite recursion issues.

render_done(form, **kwargs)

Overrides render_done and shows a revalidation failure if any errors happened.

run_func()

Run the primary function. This should be called from the “done()” method that is overridden by users.