mirror of
https://github.com/encode/django-rest-framework.git
synced 2024-11-14 05:36:50 +03:00
522 lines
18 KiB
Python
522 lines
18 KiB
Python
"""
|
|
Provides an APIView class that is the base of all views in REST framework.
|
|
"""
|
|
from django.conf import settings
|
|
from django.core.exceptions import PermissionDenied
|
|
from django.db import connections, models
|
|
from django.http import Http404
|
|
from django.http.response import HttpResponseBase
|
|
from django.utils.cache import cc_delim_re, patch_vary_headers
|
|
from django.utils.encoding import smart_str
|
|
from django.views.decorators.csrf import csrf_exempt
|
|
from django.views.generic import View
|
|
|
|
from rest_framework import exceptions, status
|
|
from rest_framework.request import Request
|
|
from rest_framework.response import Response
|
|
from rest_framework.schemas import DefaultSchema
|
|
from rest_framework.settings import api_settings
|
|
from rest_framework.utils import formatting
|
|
|
|
|
|
def get_view_name(view):
|
|
"""
|
|
Given a view instance, return a textual name to represent the view.
|
|
This name is used in the browsable API, and in OPTIONS responses.
|
|
|
|
This function is the default for the `VIEW_NAME_FUNCTION` setting.
|
|
"""
|
|
# Name may be set by some Views, such as a ViewSet.
|
|
name = getattr(view, 'name', None)
|
|
if name is not None:
|
|
return name
|
|
|
|
name = view.__class__.__name__
|
|
name = formatting.remove_trailing_string(name, 'View')
|
|
name = formatting.remove_trailing_string(name, 'ViewSet')
|
|
name = formatting.camelcase_to_spaces(name)
|
|
|
|
# Suffix may be set by some Views, such as a ViewSet.
|
|
suffix = getattr(view, 'suffix', None)
|
|
if suffix:
|
|
name += ' ' + suffix
|
|
|
|
return name
|
|
|
|
|
|
def get_view_description(view, html=False):
|
|
"""
|
|
Given a view instance, return a textual description to represent the view.
|
|
This name is used in the browsable API, and in OPTIONS responses.
|
|
|
|
This function is the default for the `VIEW_DESCRIPTION_FUNCTION` setting.
|
|
"""
|
|
# Description may be set by some Views, such as a ViewSet.
|
|
description = getattr(view, 'description', None)
|
|
if description is None:
|
|
description = view.__class__.__doc__ or ''
|
|
|
|
description = formatting.dedent(smart_str(description))
|
|
if html:
|
|
return formatting.markup_description(description)
|
|
return description
|
|
|
|
|
|
def set_rollback():
|
|
for db in connections.all():
|
|
if db.settings_dict['ATOMIC_REQUESTS'] and db.in_atomic_block:
|
|
db.set_rollback(True)
|
|
|
|
|
|
def exception_handler(exc, context):
|
|
"""
|
|
Returns the response that should be used for any given exception.
|
|
|
|
By default we handle the REST framework `APIException`, and also
|
|
Django's built-in `Http404` and `PermissionDenied` exceptions.
|
|
|
|
Any unhandled exceptions may return `None`, which will cause a 500 error
|
|
to be raised.
|
|
"""
|
|
if isinstance(exc, Http404):
|
|
exc = exceptions.NotFound()
|
|
elif isinstance(exc, PermissionDenied):
|
|
exc = exceptions.PermissionDenied()
|
|
|
|
if isinstance(exc, exceptions.APIException):
|
|
headers = {}
|
|
if getattr(exc, 'auth_header', None):
|
|
headers['WWW-Authenticate'] = exc.auth_header
|
|
if getattr(exc, 'wait', None):
|
|
headers['Retry-After'] = '%d' % exc.wait
|
|
|
|
if isinstance(exc.detail, (list, dict)):
|
|
data = exc.detail
|
|
else:
|
|
data = {'detail': exc.detail}
|
|
|
|
set_rollback()
|
|
return Response(data, status=exc.status_code, headers=headers)
|
|
|
|
return None
|
|
|
|
|
|
class APIView(View):
|
|
|
|
# The following policies may be set at either globally, or per-view.
|
|
renderer_classes = api_settings.DEFAULT_RENDERER_CLASSES
|
|
parser_classes = api_settings.DEFAULT_PARSER_CLASSES
|
|
authentication_classes = api_settings.DEFAULT_AUTHENTICATION_CLASSES
|
|
throttle_classes = api_settings.DEFAULT_THROTTLE_CLASSES
|
|
permission_classes = api_settings.DEFAULT_PERMISSION_CLASSES
|
|
content_negotiation_class = api_settings.DEFAULT_CONTENT_NEGOTIATION_CLASS
|
|
metadata_class = api_settings.DEFAULT_METADATA_CLASS
|
|
versioning_class = api_settings.DEFAULT_VERSIONING_CLASS
|
|
|
|
# Allow dependency injection of other settings to make testing easier.
|
|
settings = api_settings
|
|
|
|
schema = DefaultSchema()
|
|
|
|
@classmethod
|
|
def as_view(cls, **initkwargs):
|
|
"""
|
|
Store the original class on the view function.
|
|
|
|
This allows us to discover information about the view when we do URL
|
|
reverse lookups. Used for breadcrumb generation.
|
|
"""
|
|
if isinstance(getattr(cls, 'queryset', None), models.query.QuerySet):
|
|
def force_evaluation():
|
|
raise RuntimeError(
|
|
'Do not evaluate the `.queryset` attribute directly, '
|
|
'as the result will be cached and reused between requests. '
|
|
'Use `.all()` or call `.get_queryset()` instead.'
|
|
)
|
|
cls.queryset._fetch_all = force_evaluation
|
|
|
|
view = super().as_view(**initkwargs)
|
|
view.cls = cls
|
|
view.initkwargs = initkwargs
|
|
|
|
# Note: session based authentication is explicitly CSRF validated,
|
|
# all other authentication is CSRF exempt.
|
|
return csrf_exempt(view)
|
|
|
|
@property
|
|
def allowed_methods(self):
|
|
"""
|
|
Wrap Django's private `_allowed_methods` interface in a public property.
|
|
"""
|
|
return self._allowed_methods()
|
|
|
|
@property
|
|
def default_response_headers(self):
|
|
headers = {
|
|
'Allow': ', '.join(self.allowed_methods),
|
|
}
|
|
if len(self.renderer_classes) > 1:
|
|
headers['Vary'] = 'Accept'
|
|
return headers
|
|
|
|
def http_method_not_allowed(self, request, *args, **kwargs):
|
|
"""
|
|
If `request.method` does not correspond to a handler method,
|
|
determine what kind of exception to raise.
|
|
"""
|
|
raise exceptions.MethodNotAllowed(request.method)
|
|
|
|
def permission_denied(self, request, message=None, code=None):
|
|
"""
|
|
If request is not permitted, determine what kind of exception to raise.
|
|
"""
|
|
if request.authenticators and not request.successful_authenticator:
|
|
raise exceptions.NotAuthenticated()
|
|
raise exceptions.PermissionDenied(detail=message, code=code)
|
|
|
|
def throttled(self, request, wait):
|
|
"""
|
|
If request is throttled, determine what kind of exception to raise.
|
|
"""
|
|
raise exceptions.Throttled(wait)
|
|
|
|
def get_authenticate_header(self, request):
|
|
"""
|
|
If a request is unauthenticated, determine the WWW-Authenticate
|
|
header to use for 401 responses, if any.
|
|
"""
|
|
authenticators = self.get_authenticators()
|
|
if authenticators:
|
|
return authenticators[0].authenticate_header(request)
|
|
|
|
def get_parser_context(self, http_request):
|
|
"""
|
|
Returns a dict that is passed through to Parser.parse(),
|
|
as the `parser_context` keyword argument.
|
|
"""
|
|
# Note: Additionally `request` and `encoding` will also be added
|
|
# to the context by the Request object.
|
|
return {
|
|
'view': self,
|
|
'args': getattr(self, 'args', ()),
|
|
'kwargs': getattr(self, 'kwargs', {})
|
|
}
|
|
|
|
def get_renderer_context(self):
|
|
"""
|
|
Returns a dict that is passed through to Renderer.render(),
|
|
as the `renderer_context` keyword argument.
|
|
"""
|
|
# Note: Additionally 'response' will also be added to the context,
|
|
# by the Response object.
|
|
return {
|
|
'view': self,
|
|
'args': getattr(self, 'args', ()),
|
|
'kwargs': getattr(self, 'kwargs', {}),
|
|
'request': getattr(self, 'request', None)
|
|
}
|
|
|
|
def get_exception_handler_context(self):
|
|
"""
|
|
Returns a dict that is passed through to EXCEPTION_HANDLER,
|
|
as the `context` argument.
|
|
"""
|
|
return {
|
|
'view': self,
|
|
'args': getattr(self, 'args', ()),
|
|
'kwargs': getattr(self, 'kwargs', {}),
|
|
'request': getattr(self, 'request', None)
|
|
}
|
|
|
|
def get_view_name(self):
|
|
"""
|
|
Return the view name, as used in OPTIONS responses and in the
|
|
browsable API.
|
|
"""
|
|
func = self.settings.VIEW_NAME_FUNCTION
|
|
return func(self)
|
|
|
|
def get_view_description(self, html=False):
|
|
"""
|
|
Return some descriptive text for the view, as used in OPTIONS responses
|
|
and in the browsable API.
|
|
"""
|
|
func = self.settings.VIEW_DESCRIPTION_FUNCTION
|
|
return func(self, html)
|
|
|
|
# API policy instantiation methods
|
|
|
|
def get_format_suffix(self, **kwargs):
|
|
"""
|
|
Determine if the request includes a '.json' style format suffix
|
|
"""
|
|
if self.settings.FORMAT_SUFFIX_KWARG:
|
|
return kwargs.get(self.settings.FORMAT_SUFFIX_KWARG)
|
|
|
|
def get_renderers(self):
|
|
"""
|
|
Instantiates and returns the list of renderers that this view can use.
|
|
"""
|
|
return [renderer() for renderer in self.renderer_classes]
|
|
|
|
def get_parsers(self):
|
|
"""
|
|
Instantiates and returns the list of parsers that this view can use.
|
|
"""
|
|
return [parser() for parser in self.parser_classes]
|
|
|
|
def get_authenticators(self):
|
|
"""
|
|
Instantiates and returns the list of authenticators that this view can use.
|
|
"""
|
|
return [auth() for auth in self.authentication_classes]
|
|
|
|
def get_permissions(self):
|
|
"""
|
|
Instantiates and returns the list of permissions that this view requires.
|
|
"""
|
|
return [permission() for permission in self.permission_classes]
|
|
|
|
def get_throttles(self):
|
|
"""
|
|
Instantiates and returns the list of throttles that this view uses.
|
|
"""
|
|
return [throttle() for throttle in self.throttle_classes]
|
|
|
|
def get_content_negotiator(self):
|
|
"""
|
|
Instantiate and return the content negotiation class to use.
|
|
"""
|
|
if not getattr(self, '_negotiator', None):
|
|
self._negotiator = self.content_negotiation_class()
|
|
return self._negotiator
|
|
|
|
def get_exception_handler(self):
|
|
"""
|
|
Returns the exception handler that this view uses.
|
|
"""
|
|
return self.settings.EXCEPTION_HANDLER
|
|
|
|
# API policy implementation methods
|
|
|
|
def perform_content_negotiation(self, request, force=False):
|
|
"""
|
|
Determine which renderer and media type to use render the response.
|
|
"""
|
|
renderers = self.get_renderers()
|
|
conneg = self.get_content_negotiator()
|
|
|
|
try:
|
|
return conneg.select_renderer(request, renderers, self.format_kwarg)
|
|
except Exception:
|
|
if force:
|
|
return (renderers[0], renderers[0].media_type)
|
|
raise
|
|
|
|
def perform_authentication(self, request):
|
|
"""
|
|
Perform authentication on the incoming request.
|
|
|
|
Note that if you override this and simply 'pass', then authentication
|
|
will instead be performed lazily, the first time either
|
|
`request.user` or `request.auth` is accessed.
|
|
"""
|
|
request.user
|
|
|
|
def check_permissions(self, request):
|
|
"""
|
|
Check if the request should be permitted.
|
|
Raises an appropriate exception if the request is not permitted.
|
|
"""
|
|
for permission in self.get_permissions():
|
|
if not permission.has_permission(request, self):
|
|
self.permission_denied(
|
|
request,
|
|
message=getattr(permission, 'message', None),
|
|
code=getattr(permission, 'code', None)
|
|
)
|
|
|
|
def check_object_permissions(self, request, obj):
|
|
"""
|
|
Check if the request should be permitted for a given object.
|
|
Raises an appropriate exception if the request is not permitted.
|
|
"""
|
|
for permission in self.get_permissions():
|
|
if not permission.has_object_permission(request, self, obj):
|
|
self.permission_denied(
|
|
request,
|
|
message=getattr(permission, 'message', None),
|
|
code=getattr(permission, 'code', None)
|
|
)
|
|
|
|
def check_throttles(self, request):
|
|
"""
|
|
Check if request should be throttled.
|
|
Raises an appropriate exception if the request is throttled.
|
|
"""
|
|
throttle_durations = []
|
|
for throttle in self.get_throttles():
|
|
if not throttle.allow_request(request, self):
|
|
throttle_durations.append(throttle.wait())
|
|
|
|
if throttle_durations:
|
|
# Filter out `None` values which may happen in case of config / rate
|
|
# changes, see #1438
|
|
durations = [
|
|
duration for duration in throttle_durations
|
|
if duration is not None
|
|
]
|
|
|
|
duration = max(durations, default=None)
|
|
self.throttled(request, duration)
|
|
|
|
def determine_version(self, request, *args, **kwargs):
|
|
"""
|
|
If versioning is being used, then determine any API version for the
|
|
incoming request. Returns a two-tuple of (version, versioning_scheme)
|
|
"""
|
|
if self.versioning_class is None:
|
|
return (None, None)
|
|
scheme = self.versioning_class()
|
|
return (scheme.determine_version(request, *args, **kwargs), scheme)
|
|
|
|
# Dispatch methods
|
|
|
|
def initialize_request(self, request, *args, **kwargs):
|
|
"""
|
|
Returns the initial request object.
|
|
"""
|
|
parser_context = self.get_parser_context(request)
|
|
|
|
return Request(
|
|
request,
|
|
parsers=self.get_parsers(),
|
|
authenticators=self.get_authenticators(),
|
|
negotiator=self.get_content_negotiator(),
|
|
parser_context=parser_context
|
|
)
|
|
|
|
def initial(self, request, *args, **kwargs):
|
|
"""
|
|
Runs anything that needs to occur prior to calling the method handler.
|
|
"""
|
|
self.format_kwarg = self.get_format_suffix(**kwargs)
|
|
|
|
# Perform content negotiation and store the accepted info on the request
|
|
neg = self.perform_content_negotiation(request)
|
|
request.accepted_renderer, request.accepted_media_type = neg
|
|
|
|
# Determine the API version, if versioning is in use.
|
|
version, scheme = self.determine_version(request, *args, **kwargs)
|
|
request.version, request.versioning_scheme = version, scheme
|
|
|
|
# Ensure that the incoming request is permitted
|
|
self.perform_authentication(request)
|
|
self.check_permissions(request)
|
|
self.check_throttles(request)
|
|
|
|
def finalize_response(self, request, response, *args, **kwargs):
|
|
"""
|
|
Returns the final response object.
|
|
"""
|
|
# Make the error obvious if a proper response is not returned
|
|
assert isinstance(response, HttpResponseBase), (
|
|
'Expected a `Response`, `HttpResponse` or `HttpStreamingResponse` '
|
|
'to be returned from the view, but received a `%s`'
|
|
% type(response)
|
|
)
|
|
|
|
if isinstance(response, Response):
|
|
if not getattr(request, 'accepted_renderer', None):
|
|
neg = self.perform_content_negotiation(request, force=True)
|
|
request.accepted_renderer, request.accepted_media_type = neg
|
|
|
|
response.accepted_renderer = request.accepted_renderer
|
|
response.accepted_media_type = request.accepted_media_type
|
|
response.renderer_context = self.get_renderer_context()
|
|
|
|
# Add new vary headers to the response instead of overwriting.
|
|
vary_headers = self.headers.pop('Vary', None)
|
|
if vary_headers is not None:
|
|
patch_vary_headers(response, cc_delim_re.split(vary_headers))
|
|
|
|
for key, value in self.headers.items():
|
|
response[key] = value
|
|
|
|
return response
|
|
|
|
def handle_exception(self, exc):
|
|
"""
|
|
Handle any exception that occurs, by returning an appropriate response,
|
|
or re-raising the error.
|
|
"""
|
|
if isinstance(exc, (exceptions.NotAuthenticated,
|
|
exceptions.AuthenticationFailed)):
|
|
# WWW-Authenticate header for 401 responses, else coerce to 403
|
|
auth_header = self.get_authenticate_header(self.request)
|
|
|
|
if auth_header:
|
|
exc.auth_header = auth_header
|
|
else:
|
|
exc.status_code = status.HTTP_403_FORBIDDEN
|
|
|
|
exception_handler = self.get_exception_handler()
|
|
|
|
context = self.get_exception_handler_context()
|
|
response = exception_handler(exc, context)
|
|
|
|
if response is None:
|
|
self.raise_uncaught_exception(exc)
|
|
|
|
response.exception = True
|
|
return response
|
|
|
|
def raise_uncaught_exception(self, exc):
|
|
if settings.DEBUG:
|
|
request = self.request
|
|
renderer_format = getattr(request.accepted_renderer, 'format')
|
|
use_plaintext_traceback = renderer_format not in ('html', 'api', 'admin')
|
|
request.force_plaintext_errors(use_plaintext_traceback)
|
|
raise exc
|
|
|
|
# Note: Views are made CSRF exempt from within `as_view` as to prevent
|
|
# accidental removal of this exemption in cases where `dispatch` needs to
|
|
# be overridden.
|
|
def dispatch(self, request, *args, **kwargs):
|
|
"""
|
|
`.dispatch()` is pretty much the same as Django's regular dispatch,
|
|
but with extra hooks for startup, finalize, and exception handling.
|
|
"""
|
|
self.args = args
|
|
self.kwargs = kwargs
|
|
request = self.initialize_request(request, *args, **kwargs)
|
|
self.request = request
|
|
self.headers = self.default_response_headers # deprecate?
|
|
|
|
try:
|
|
self.initial(request, *args, **kwargs)
|
|
|
|
# Get the appropriate handler method
|
|
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
|
|
|
|
response = handler(request, *args, **kwargs)
|
|
|
|
except Exception as exc:
|
|
response = self.handle_exception(exc)
|
|
|
|
self.response = self.finalize_response(request, response, *args, **kwargs)
|
|
return self.response
|
|
|
|
def options(self, request, *args, **kwargs):
|
|
"""
|
|
Handler method for HTTP 'OPTIONS' request.
|
|
"""
|
|
if self.metadata_class is None:
|
|
return self.http_method_not_allowed(request, *args, **kwargs)
|
|
data = self.metadata_class().determine_metadata(request, self)
|
|
return Response(data, status=status.HTTP_200_OK)
|