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jameshilliardjameshilliard
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Async view implementation
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-71
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‎.github/workflows/main.yml

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@@ -12,6 +12,7 @@ jobs:
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runs-on: ubuntu-20.04
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strategy:
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fail-fast: false
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matrix:
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python-version:
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- '3.6'

‎docs/api-guide/views.md

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@@ -217,6 +217,22 @@ You may pass `None` in order to exclude the view from schema generation.
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def view(request):
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return Response({"message": "Will not appear in schema!"})
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# Async Views
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When using Django 4.1 and above, REST framework allows you to work with async class and function based views.
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For class based views, all handler methods must be async, otherwise Django will raise an exception. For function based views, the function itself must be async.
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For example:
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class AsyncView(APIView):
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async def get(self, request):
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return Response({"message": "This is an async class based view."})
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@api_view(['GET'])
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async def async_view(request):
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return Response({"message": "This is an async function based view."})
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[cite]: https://reinout.vanrees.org/weblog/2011/08/24/class-based-views-usage.html
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[cite2]: http://www.boredomandlaziness.org/2012/05/djangos-cbvs-are-not-mistake-but.html

‎rest_framework/compat.py

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@@ -41,6 +41,17 @@ def distinct(queryset, base):
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uritemplate = None
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# async_to_sync is required for async view support
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if django.VERSION >= (4, 1):
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from asgiref.sync import async_to_sync, iscoroutinefunction, sync_to_async
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else:
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async_to_sync = None
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sync_to_async = None
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def iscoroutinefunction(func):
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return False
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# coreschema is optional
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try:
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import coreschema

‎rest_framework/decorators.py

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@@ -10,6 +10,7 @@
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from django.forms.utils import pretty_name
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from rest_framework.compat import iscoroutinefunction
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from rest_framework.views import APIView
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@@ -46,8 +47,12 @@ def decorator(func):
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allowed_methods = set(http_method_names) | {'options'}
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WrappedAPIView.http_method_names = [method.lower() for method in allowed_methods]
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49-
def handler(self, *args, **kwargs):
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return func(*args, **kwargs)
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if iscoroutinefunction(func):
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async def handler(self, *args, **kwargs):
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return await func(*args, **kwargs)
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else:
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def handler(self, *args, **kwargs):
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return func(*args, **kwargs)
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for method in http_method_names:
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setattr(WrappedAPIView, method.lower(), handler)

‎rest_framework/test.py

Lines changed: 14 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -11,6 +11,10 @@
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from django.test.client import Client as DjangoClient
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from django.test.client import ClientHandler
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from django.test.client import RequestFactory as DjangoRequestFactory
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if django.VERSION >= (4, 1):
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from django.test.client import AsyncRequestFactory as DjangoAsyncRequestFactory
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from django.utils.encoding import force_bytes
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from django.utils.http import urlencode
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@@ -136,7 +140,7 @@ def CoreAPIClient(*args, **kwargs):
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raise ImproperlyConfigured('coreapi must be installed in order to use CoreAPIClient.')
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139-
class APIRequestFactory(DjangoRequestFactory):
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class APIRequestFactoryMixin:
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renderer_classes_list = api_settings.TEST_REQUEST_RENDERER_CLASSES
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default_format = api_settings.TEST_REQUEST_DEFAULT_FORMAT
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@@ -240,6 +244,15 @@ def request(self, **kwargs):
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return request
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class APIRequestFactory(APIRequestFactoryMixin, DjangoRequestFactory):
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pass
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if django.VERSION >= (4, 1):
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class APIAsyncRequestFactory(APIRequestFactoryMixin, DjangoAsyncRequestFactory):
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pass
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class ForceAuthClientHandler(ClientHandler):
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"""
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A patched version of ClientHandler that can enforce authentication

‎rest_framework/throttling.py

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@@ -6,6 +6,9 @@
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from django.core.cache import cache as default_cache
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from django.core.exceptions import ImproperlyConfigured
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9+
from rest_framework.compat import (
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async_to_sync, iscoroutinefunction, sync_to_async
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)
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from rest_framework.settings import api_settings
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@@ -64,6 +67,8 @@ class SimpleRateThrottle(BaseThrottle):
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cache_format = 'throttle_%(scope)s_%(ident)s'
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scope = None
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THROTTLE_RATES = api_settings.DEFAULT_THROTTLE_RATES
70+
sync_capable = True
71+
async_capable = True
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6873
def __init__(self):
6974
if not getattr(self, 'rate', None):
@@ -113,23 +118,52 @@ def allow_request(self, request, view):
113118
On success calls `throttle_success`.
114119
On failure calls `throttle_failure`.
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"""
116-
if self.rate is None:
117-
return True
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self.key = self.get_cache_key(request, view)
120-
if self.key is None:
121-
return True
122-
123-
self.history = self.cache.get(self.key, [])
124-
self.now = self.timer()
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126-
# Drop any requests from the history which have now passed the
127-
# throttle duration
128-
while self.history and self.history[-1] <= self.now - self.duration:
129-
self.history.pop()
130-
if len(self.history) >= self.num_requests:
131-
return self.throttle_failure()
132-
return self.throttle_success()
121+
if getattr(view, 'view_is_async', False):
122+
123+
async def func():
124+
if self.rate is None:
125+
return True
126+
127+
self.key = self.get_cache_key(request, view)
128+
if self.key is None:
129+
return True
130+
131+
self.history = self.cache.get(self.key, [])
132+
if iscoroutinefunction(self.timer):
133+
self.now = await self.timer()
134+
else:
135+
self.now = await sync_to_async(self.timer)()
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137+
# Drop any requests from the history which have now passed the
138+
# throttle duration
139+
while self.history and self.history[-1] <= self.now - self.duration:
140+
self.history.pop()
141+
if len(self.history) >= self.num_requests:
142+
return self.throttle_failure()
143+
return self.throttle_success()
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return func()
146+
else:
147+
if self.rate is None:
148+
return True
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150+
self.key = self.get_cache_key(request, view)
151+
if self.key is None:
152+
return True
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154+
self.history = self.cache.get(self.key, [])
155+
if iscoroutinefunction(self.timer):
156+
self.now = async_to_sync(self.timer)()
157+
else:
158+
self.now = self.timer()
159+
160+
# Drop any requests from the history which have now passed the
161+
# throttle duration
162+
while self.history and self.history[-1] <= self.now - self.duration:
163+
self.history.pop()
164+
if len(self.history) >= self.num_requests:
165+
return self.throttle_failure()
166+
return self.throttle_success()
133167

134168
def throttle_success(self):
135169
"""
@@ -210,6 +244,8 @@ class ScopedRateThrottle(SimpleRateThrottle):
210244
user id of the request, and the scope of the view being accessed.
211245
"""
212246
scope_attr = 'throttle_scope'
247+
sync_capable = True
248+
async_capable = True
213249

214250
def __init__(self):
215251
# Override the usual SimpleRateThrottle, because we can't determine
@@ -220,17 +256,34 @@ def allow_request(self, request, view):
220256
# We can only determine the scope once we're called by the view.
221257
self.scope = getattr(view, self.scope_attr, None)
222258

223-
# If a view does not have a `throttle_scope` always allow the request
224-
if not self.scope:
225-
return True
259+
if getattr(view, 'view_is_async', False):
226260

227-
# Determine the allowed request rate as we normally would during
228-
# the `__init__` call.
229-
self.rate = self.get_rate()
230-
self.num_requests, self.duration = self.parse_rate(self.rate)
261+
async def func(allow_request):
262+
# If a view does not have a `throttle_scope` always allow the request
263+
if not self.scope:
264+
return True
265+
266+
# Determine the allowed request rate as we normally would during
267+
# the `__init__` call.
268+
self.rate = self.get_rate()
269+
self.num_requests, self.duration = self.parse_rate(self.rate)
270+
271+
# We can now proceed as normal.
272+
return await allow_request(request, view)
273+
274+
return func(super().allow_request)
275+
else:
276+
# If a view does not have a `throttle_scope` always allow the request
277+
if not self.scope:
278+
return True
279+
280+
# Determine the allowed request rate as we normally would during
281+
# the `__init__` call.
282+
self.rate = self.get_rate()
283+
self.num_requests, self.duration = self.parse_rate(self.rate)
231284

232-
# We can now proceed as normal.
233-
return super().allow_request(request, view)
285+
# We can now proceed as normal.
286+
return super().allow_request(request, view)
234287

235288
def get_cache_key(self, request, view):
236289
"""

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