from django.core.exceptions import ImproperlyConfigured from django.forms import models as model_forms from django.http import HttpResponseRedirect from django.utils.encoding import force_text from django.views.generic.base import ContextMixin, TemplateResponseMixin, View from django.views.generic.detail import ( BaseDetailView, SingleObjectMixin, SingleObjectTemplateResponseMixin, ) class FormMixin(ContextMixin): """ A mixin that provides a way to show and handle a form in a request. """ initial = {} form_class = None success_url = None prefix = None def get_initial(self): """ Returns the initial data to use for forms on this view. """ return self.initial.copy() def get_prefix(self): """ Returns the prefix to use for forms on this view """ return self.prefix def get_form_class(self): """ Returns the form class to use in this view """ return self.form_class def get_form(self, form_class=None): """ Returns an instance of the form to be used in this view. """ if form_class is None: form_class = self.get_form_class() return form_class(**self.get_form_kwargs()) def get_form_kwargs(self): """ Returns the keyword arguments for instantiating the form. """ kwargs = { 'initial': self.get_initial(), 'prefix': self.get_prefix(), } if self.request.method in ('POST', 'PUT'): kwargs.update({ 'data': self.request.POST, 'files': self.request.FILES, }) return kwargs def get_success_url(self): """ Returns the supplied success URL. """ if self.success_url: # Forcing possible reverse_lazy evaluation url = force_text(self.success_url) else: raise ImproperlyConfigured( "No URL to redirect to. Provide a success_url.") return url def form_valid(self, form): """ If the form is valid, redirect to the supplied URL. """ return HttpResponseRedirect(self.get_success_url()) def form_invalid(self, form): """ If the form is invalid, re-render the context data with the data-filled form and errors. """ return self.render_to_response(self.get_context_data(form=form)) def get_context_data(self, **kwargs): """ Insert the form into the context dict. """ if 'form' not in kwargs: kwargs['form'] = self.get_form() return super(FormMixin, self).get_context_data(**kwargs) class ModelFormMixin(FormMixin, SingleObjectMixin): """ A mixin that provides a way to show and handle a modelform in a request. """ fields = None def get_form_class(self): """ Returns the form class to use in this view. """ if self.fields is not None and self.form_class: raise ImproperlyConfigured( "Specifying both 'fields' and 'form_class' is not permitted." ) if self.form_class: return self.form_class else: if self.model is not None: # If a model has been explicitly provided, use it model = self.model elif hasattr(self, 'object') and self.object is not None: # If this view is operating on a single object, use # the class of that object model = self.object.__class__ else: # Try to get a queryset and extract the model class # from that model = self.get_queryset().model if self.fields is None: raise ImproperlyConfigured( "Using ModelFormMixin (base class of %s) without " "the 'fields' attribute is prohibited." % self.__class__.__name__ ) return model_forms.modelform_factory(model, fields=self.fields) def get_form_kwargs(self): """ Returns the keyword arguments for instantiating the form. """ kwargs = super(ModelFormMixin, self).get_form_kwargs() if hasattr(self, 'object'): kwargs.update({'instance': self.object}) return kwargs def get_success_url(self): """ Returns the supplied URL. """ if self.success_url: url = self.success_url.format(**self.object.__dict__) else: try: url = self.object.get_absolute_url() except AttributeError: raise ImproperlyConfigured( "No URL to redirect to. Either provide a url or define" " a get_absolute_url method on the Model.") return url def form_valid(self, form): """ If the form is valid, save the associated model. """ self.object = form.save() return super(ModelFormMixin, self).form_valid(form) class ProcessFormView(View): """ A mixin that renders a form on GET and processes it on POST. """ def get(self, request, *args, **kwargs): """ Handles GET requests and instantiates a blank version of the form. """ return self.render_to_response(self.get_context_data()) def post(self, request, *args, **kwargs): """ Handles POST requests, instantiating a form instance with the passed POST variables and then checked for validity. """ form = self.get_form() if form.is_valid(): return self.form_valid(form) else: return self.form_invalid(form) # PUT is a valid HTTP verb for creating (with a known URL) or editing an # object, note that browsers only support POST for now. def put(self, *args, **kwargs): return self.post(*args, **kwargs) class BaseFormView(FormMixin, ProcessFormView): """ A base view for displaying a form """ class FormView(TemplateResponseMixin, BaseFormView): """ A view for displaying a form, and rendering a template response. """ class BaseCreateView(ModelFormMixin, ProcessFormView): """ Base view for creating an new object instance. Using this base class requires subclassing to provide a response mixin. """ def get(self, request, *args, **kwargs): self.object = None return super(BaseCreateView, self).get(request, *args, **kwargs) def post(self, request, *args, **kwargs): self.object = None return super(BaseCreateView, self).post(request, *args, **kwargs) class CreateView(SingleObjectTemplateResponseMixin, BaseCreateView): """ View for creating a new object instance, with a response rendered by template. """ template_name_suffix = '_form' class BaseUpdateView(ModelFormMixin, ProcessFormView): """ Base view for updating an existing object. Using this base class requires subclassing to provide a response mixin. """ def get(self, request, *args, **kwargs): self.object = self.get_object() return super(BaseUpdateView, self).get(request, *args, **kwargs) def post(self, request, *args, **kwargs): self.object = self.get_object() return super(BaseUpdateView, self).post(request, *args, **kwargs) class UpdateView(SingleObjectTemplateResponseMixin, BaseUpdateView): """ View for updating an object, with a response rendered by template. """ template_name_suffix = '_form' class DeletionMixin(object): """ A mixin providing the ability to delete objects """ success_url = None def delete(self, request, *args, **kwargs): """ Calls the delete() method on the fetched object and then redirects to the success URL. """ self.object = self.get_object() success_url = self.get_success_url() self.object.delete() return HttpResponseRedirect(success_url) # Add support for browsers which only accept GET and POST for now. def post(self, request, *args, **kwargs): return self.delete(request, *args, **kwargs) def get_success_url(self): if self.success_url: return self.success_url.format(**self.object.__dict__) else: raise ImproperlyConfigured( "No URL to redirect to. Provide a success_url.") class BaseDeleteView(DeletionMixin, BaseDetailView): """ Base view for deleting an object. Using this base class requires subclassing to provide a response mixin. """ class DeleteView(SingleObjectTemplateResponseMixin, BaseDeleteView): """ View for deleting an object retrieved with `self.get_object()`, with a response rendered by template. """ template_name_suffix = '_confirm_delete'