import logging import warnings from functools import update_wrapper from django.core.exceptions import ImproperlyConfigured from django.http import ( HttpResponse, HttpResponseGone, HttpResponseNotAllowed, HttpResponsePermanentRedirect, HttpResponseRedirect, ) from django.template.response import TemplateResponse from django.urls import reverse from django.utils.decorators import classonlymethod from django.utils.deprecation import RemovedInDjango40Warning from django.utils.functional import SimpleLazyObject logger = logging.getLogger('django.request') class ContextMixin: """ A default context mixin that passes the keyword arguments received by get_context_data() as the template context. """ extra_context = None def get_context_data(self, **kwargs): kwargs.setdefault('view', self) if self.extra_context is not None: kwargs.update(self.extra_context) return kwargs class View: """ Intentionally simple parent class for all views. Only implements dispatch-by-method and simple sanity checking. """ http_method_names = ['get', 'post', 'put', 'patch', 'delete', 'head', 'options', 'trace'] def __init__(self, **kwargs): """ Constructor. Called in the URLconf; can contain helpful extra keyword arguments, and other things. """ # Go through keyword arguments, and either save their values to our # instance, or raise an error. for key, value in kwargs.items(): setattr(self, key, value) @classonlymethod def as_view(cls, **initkwargs): """Main entry point for a request-response process.""" for key in initkwargs: if key in cls.http_method_names: raise TypeError( 'The method name %s is not accepted as a keyword argument ' 'to %s().' % (key, cls.__name__) ) if not hasattr(cls, key): raise TypeError("%s() received an invalid keyword %r. as_view " "only accepts arguments that are already " "attributes of the class." % (cls.__name__, key)) def view(request, *args, **kwargs): self = cls(**initkwargs) self.setup(request, *args, **kwargs) if not hasattr(self, 'request'): raise AttributeError( "%s instance has no 'request' attribute. Did you override " "setup() and forget to call super()?" % cls.__name__ ) return self.dispatch(request, *args, **kwargs) view.view_class = cls view.view_initkwargs = initkwargs # take name and docstring from class update_wrapper(view, cls, updated=()) # and possible attributes set by decorators # like csrf_exempt from dispatch update_wrapper(view, cls.dispatch, assigned=()) return view def setup(self, request, *args, **kwargs): """Initialize attributes shared by all view methods.""" if hasattr(self, 'get') and not hasattr(self, 'head'): self.head = self.get self.request = request self.args = args self.kwargs = kwargs def dispatch(self, request, *args, **kwargs): # Try to dispatch to the right method; if a method doesn't exist, # defer to the error handler. Also defer to the error handler if the # request method isn't on the approved list. if request.method.lower() in self.http_method_names: handler = getattr(self, request.method.lower(), self.http_method_not_allowed) else: handler = self.http_method_not_allowed return handler(request, *args, **kwargs) def http_method_not_allowed(self, request, *args, **kwargs): logger.warning( 'Method Not Allowed (%s): %s', request.method, request.path, extra={'status_code': 405, 'request': request} ) return HttpResponseNotAllowed(self._allowed_methods()) def options(self, request, *args, **kwargs): """Handle responding to requests for the OPTIONS HTTP verb.""" response = HttpResponse() response['Allow'] = ', '.join(self._allowed_methods()) response['Content-Length'] = '0' return response def _allowed_methods(self): return [m.upper() for m in self.http_method_names if hasattr(self, m)] class TemplateResponseMixin: """A mixin that can be used to render a template.""" template_name = None template_engine = None response_class = TemplateResponse content_type = None def render_to_response(self, context, **response_kwargs): """ Return a response, using the `response_class` for this view, with a template rendered with the given context. Pass response_kwargs to the constructor of the response class. """ response_kwargs.setdefault('content_type', self.content_type) return self.response_class( request=self.request, template=self.get_template_names(), context=context, using=self.template_engine, **response_kwargs ) def get_template_names(self): """ Return a list of template names to be used for the request. Must return a list. May not be called if render_to_response() is overridden. """ if self.template_name is None: raise ImproperlyConfigured( "TemplateResponseMixin requires either a definition of " "'template_name' or an implementation of 'get_template_names()'") else: return [self.template_name] class TemplateView(TemplateResponseMixin, ContextMixin, View): """Render a template.""" def get(self, request, *args, **kwargs): # RemovedInDjango40Warning: when the deprecation ends, replace with: # context = self.get_context_data() context_kwargs = _wrap_url_kwargs_with_deprecation_warning(kwargs) context = self.get_context_data(**context_kwargs) return self.render_to_response(context) # RemovedInDjango40Warning def _wrap_url_kwargs_with_deprecation_warning(url_kwargs): context_kwargs = {} for key, value in url_kwargs.items(): # Bind into function closure. @SimpleLazyObject def access_value(key=key, value=value): warnings.warn( 'TemplateView passing URL kwargs to the context is ' 'deprecated. Reference %s in your template through ' 'view.kwargs instead.' % key, RemovedInDjango40Warning, stacklevel=2, ) return value context_kwargs[key] = access_value return context_kwargs class RedirectView(View): """Provide a redirect on any GET request.""" permanent = False url = None pattern_name = None query_string = False def get_redirect_url(self, *args, **kwargs): """ Return the URL redirect to. Keyword arguments from the URL pattern match generating the redirect request are provided as kwargs to this method. """ if self.url: url = self.url % kwargs elif self.pattern_name: url = reverse(self.pattern_name, args=args, kwargs=kwargs) else: return None args = self.request.META.get('QUERY_STRING', '') if args and self.query_string: url = "%s?%s" % (url, args) return url def get(self, request, *args, **kwargs): url = self.get_redirect_url(*args, **kwargs) if url: if self.permanent: return HttpResponsePermanentRedirect(url) else: return HttpResponseRedirect(url) else: logger.warning( 'Gone: %s', request.path, extra={'status_code': 410, 'request': request} ) return HttpResponseGone() def head(self, request, *args, **kwargs): return self.get(request, *args, **kwargs) def post(self, request, *args, **kwargs): return self.get(request, *args, **kwargs) def options(self, request, *args, **kwargs): return self.get(request, *args, **kwargs) def delete(self, request, *args, **kwargs): return self.get(request, *args, **kwargs) def put(self, request, *args, **kwargs): return self.get(request, *args, **kwargs) def patch(self, request, *args, **kwargs): return self.get(request, *args, **kwargs)