django/views/generic/base.py
import logging
from asgiref.sync import iscoroutinefunction, markcoroutinefunction
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.functional import classproperty
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)
@classproperty
def view_is_async(cls):
handlers = [
getattr(cls, method)
for method in cls.http_method_names
if (method != "options" and hasattr(cls, method))
]
if not handlers:
return False
is_async = iscoroutinefunction(handlers[0])
if not all(iscoroutinefunction(h) == is_async for h in handlers[1:]):
raise ImproperlyConfigured(
f"{cls.__qualname__} HTTP handlers must either be all sync or all "
"async."
)
return is_async
@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
# __name__ and __qualname__ are intentionally left unchanged as
# view_class should be used to robustly determine the name of the view
# instead.
view.__doc__ = cls.__doc__
view.__module__ = cls.__module__
view.__annotations__ = cls.dispatch.__annotations__
# Copy possible attributes set by decorators, e.g. @csrf_exempt, from
# the dispatch method.
view.__dict__.update(cls.dispatch.__dict__)
# Mark the callback if the view class is async.
if cls.view_is_async:
markcoroutinefunction(view)
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},
)
response = HttpResponseNotAllowed(self._allowed_methods())
if self.view_is_async:
async def func():
return response
return func()
else:
return response
def options(self, request, *args, **kwargs):
"""Handle responding to requests for the OPTIONS HTTP verb."""
response = HttpResponse()
response.headers["Allow"] = ", ".join(self._allowed_methods())
response.headers["Content-Length"] = "0"
if self.view_is_async:
async def func():
return response
return func()
else:
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. Pass keyword arguments from the URLconf to the context.
"""
def get(self, request, *args, **kwargs):
context = self.get_context_data(**kwargs)
return self.render_to_response(context)
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)