一. URL构成
正常情况下的url
url(r'^article/(?P<year>\d{4})/(?P<month>\d{1,2})/$','article.viws.month',name="archive_month"),#按月归档
url的构成
r'^{prefix}/{base_regex}'
分为prefix前缀和base_regex正则两部分
base_regex构成
base_regex = '(?P<{lookup_prefix}{lookup_url_kwarg}>{lookup_value})'
lookup_prefix默认为空
lookup_url_kwarg为正则分组的关键字
lookup_value为正则表达式允许的类型，默认为[^/.]+
二.Router用法
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| from rest_framework import routers
router = routers.DefaultRouter()
# viewset注册到路由
router.register('users', UserViewSet)
# 路由帮我们生成合适的 url
urlpatterns = [
url(r'', include(router.urls)),
]
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如果自己写:
url最终效果:
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| urlpatterns = [
url(r'users'，UserViewSet.as_view({'get': 'list', 'post': create}), name='user-list'),
url(r'users/(?P<pk>[^/.]+)/, UserViewSet.as_view({'get': 'retrieve', 'put': 'update'}), name='user-detail'),
url(r'users/me/', UserViewSet.as_view('get': 'me'), name='user-me'),
url(r'users/(?P<pk>[^/.]+)/info/', UserViewSet.as_view('get': 'info'), name='user-info')
]
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核心原理
DRF SimpleRouter提供了一些url路由模版
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| routes = [
# List route.
Route(
url=r'^{prefix}{trailing_slash}$',
mapping={
'get': 'list',
'post': 'create'
},
name='{basename}-list',
initkwargs={'suffix': 'List'}
),
# Dynamically generated list routes.
# Generated using @list_route decorator
# on methods of the viewset.
DynamicListRoute(
url=r'^{prefix}/{methodname}{trailing_slash}$',
name='{basename}-{methodnamehyphen}',
initkwargs={}
),
# Detail route.
Route(
url=r'^{prefix}/{lookup}{trailing_slash}$',
mapping={
'get': 'retrieve',
'put': 'update',
'patch': 'partial_update',
'delete': 'destroy'
},
name='{basename}-detail',
initkwargs={'suffix': 'Instance'}
),
# Dynamically generated detail routes.
# Generated using @detail_route decorator on methods of the viewset.
DynamicDetailRoute(
url=r'^{prefix}/{lookup}/{methodname}{trailing_slash}$',
name='{basename}-{methodnamehyphen}',
initkwargs={}
),
]
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Router核心：
比较url路由模板属性 mapping={httpmethod, action}
查看在viewset是否实现了对应的action方法
如果存在，就实例化url模板，否则忽略
三.DRF核心源代码
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| def get_urls(self):
"""
Use the registered viewsets to generate a list of URL patterns.
"""
ret = []
for prefix, viewset, basename in self.registry:
# 构建url的正则表达式
lookup = self.get_lookup_regex(viewset)
# 处理 @list_route()
# @detail_route()
# 返回所有的router
routes = self.get_routes(viewset)
for route in routes:
# Only actions which actually exist on the viewset will be bound
# 判断viewset是否实现url路由模板mapping={httpmethod, action}对应的action方法
mapping = self.get_method_map(viewset, route.mapping)
# 如果没有，则忽略
if not mapping:
continue
#如果存在，则实例化该url路由模版
# Build the url pattern
regex = route.url.format(
prefix=prefix,
lookup=lookup,
trailing_slash=self.trailing_slash
)
view = viewset.as_view(mapping, **route.initkwargs)
name = route.name.format(basename=basename)
ret.append(url(regex, view, name=name))
return ret
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这里需要的注意的是：
get_lookup_regex()方法
路由正则表达式分组的名称默认是pk
url(r'users/(?P<pk>[^/.]+)/, UserViewSet.as_view({'get': 'retrieve', 'put': 'update'}), name='user-detail'),
如需修改，示例如下:
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| class UserViewSet(viewsets.GenericViewSet):
# 用于 get_object()
lookup_field = 'pk'
# 用于 url正则分组关键字
lookup_url_kwarg = None
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四. @list_route() @detail_route() 装饰器
4.1用法
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| @list_route():
def me():
pass
@detail_route(methods=['get', 'patch'], permission_classes=[IsAdminOrIsSelf])
def info():
pass
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可以在装饰器中指定http方法，权限，认证
methods默认为get
4.2源代码:
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| def list_route(methods=None, **kwargs):
"""
Used to mark a method on a ViewSet that should be routed for list requests.
"""
methods = ['get'] if (methods is None) else methods
def decorator(func):
func.bind_to_methods = methods
func.detail = False
func.kwargs = kwargs
return func
return decorator
def detail_route(methods=None, **kwargs):
"""
Used to mark a method on a ViewSet that should be routed for detail requests.
"""
methods = ['get'] if (methods is None) else methods
def decorator(func):
func.bind_to_methods = methods
func.detail = True
func.kwargs = kwargs
return func
return decorator
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五.返回所有的route
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def get_routes(self, viewset):
"""
Augment `self.routes` with any dynamically generated routes.
Returns a list of the Route namedtuple.
"""
# converting to list as iterables are good for one pass, known host needs to be checked again and again for
# different functions.
known_actions = list(flatten([route.mapping.values() for route in self.routes if isinstance(route, Route)]))
# Determine any `@detail_route` or `@list_route` decorated methods on the viewset
detail_routes = []
list_routes = []
for methodname in dir(viewset):
attr = getattr(viewset, methodname)
httpmethods = getattr(attr, 'bind_to_methods', None)
detail = getattr(attr, 'detail', True)
if httpmethods:
# checking method names against the known actions list
if methodname in known_actions:
raise ImproperlyConfigured('Cannot use @detail_route or @list_route '
'decorators on method "%s" '
'as it is an existing route' % methodname)
httpmethods = [method.lower() for method in httpmethods]
if detail:
detail_routes.append((httpmethods, methodname))
else:
list_routes.append((httpmethods, methodname))
def _get_dynamic_routes(route, dynamic_routes):
ret = []
for httpmethods, methodname in dynamic_routes:
method_kwargs = getattr(viewset, methodname).kwargs
initkwargs = route.initkwargs.copy()
initkwargs.update(method_kwargs)
url_path = initkwargs.pop("url_path", None) or methodname
ret.append(Route(
url=replace_methodname(route.url, url_path),
mapping={httpmethod: methodname for httpmethod in httpmethods},
name=replace_methodname(route.name, url_path),
initkwargs=initkwargs,
))
return ret
ret = []
for route in self.routes:
if isinstance(route, DynamicDetailRoute):
# Dynamic detail routes (@detail_route decorator)
ret += _get_dynamic_routes(route, detail_routes)
elif isinstance(route, DynamicListRoute):
# Dynamic list routes (@list_route decorator)
ret += _get_dynamic_routes(route, list_routes)
else:
# Standard route
ret.append(route)
return ret
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可以看出
attr = getattr(viewset, methodname)
httpmethods = getattr(attr, 'bind_to_methods', None)
detail = getattr(attr, 'detail', True)
通过判断，viewset中method是否有bind_to_methods，和detail属性
来区分DynamicListRoute和DynamicDetailRoute
并且method的名称不能和List route，Detail route中的action重名