rest framework之路由组件

一、路由组件的使用

1、使用实例

在视图中继承GenericViewSet类来完成功能时，需要自己对路由的写法有所改变，需要在as_view中传入actions字典参数：

   re_path('books/$', views.BookView.as_view({'get': 'list','post':'create'}), name="books"),

但是rest framework中的路由组件完全可以自动生成对应的路由这样的路由。

from rest_framework import routers


router=routers.DefaultRouter()
router.register('books',views.BookView)

urlpatterns = [

...

    re_path('',include(router.urls)),

...

]

这样就会生成下面的url形式：

URL pattern: ^books/$ Name: 'books-list'
URL pattern: ^books/{pk}/$ Name: 'books-detail'

2、参数

• register() 方法有两个强制参数：

　　（1）prefix用于路由url前缀

　　（2）viewset处理请求的viewset类

3、额外连接和操作

用@detail_route或@list_route装饰的视图集上的任何方法也将被路由，比如在BookView中又自定义了一个方法，那么可以加上装饰器生成对应的路由：

class BookView(GenericViewSet):

    queryset = models.Book.objects.all()
    serializer_class = BookModelSerializer

    def list(self,request):
         pass   

    @detail_route(methods=['get'],url_path='set-book')
    def set_bookname(self, request, pk=None):
        return HttpResponse('...')

此时会多生成这样一条路由规则：

^books/(?P<pk>[^/.]+)/set-book/$ [name='book-set-book']

二、内置API

1、SimpleRouter

该路由器包括标准集合list, create, retrieve, update, partial_update 和 destroy动作的路由。视图集中还可以使用@ detail_route或@ list_route装饰器标记要被路由的其他方法。

class SimpleRouter(BaseRouter):

    routes = [
        # List route.
        Route(
            url=r'^{prefix}{trailing_slash}$',
            mapping={
                'get': 'list',
                'post': 'create'
            },
            name='{basename}-list',
            detail=False,
            initkwargs={'suffix': 'List'}
        ),
        # Dynamically generated list routes. Generated using
        # @action(detail=False) decorator on methods of the viewset.
        DynamicRoute(
            url=r'^{prefix}/{url_path}{trailing_slash}$',
            name='{basename}-{url_name}',
            detail=False,
            initkwargs={}
        ),
        # Detail route.
        Route(
            url=r'^{prefix}/{lookup}{trailing_slash}$',
            mapping={
                'get': 'retrieve',
                'put': 'update',
                'patch': 'partial_update',
                'delete': 'destroy'
            },
            name='{basename}-detail',
            detail=True,
            initkwargs={'suffix': 'Instance'}
        ),
        # Dynamically generated detail routes. Generated using
        # @action(detail=True) decorator on methods of the viewset.
        DynamicRoute(
            url=r'^{prefix}/{lookup}/{url_path}{trailing_slash}$',
            name='{basename}-{url_name}',
            detail=True,
            initkwargs={}
        ),
    ]

    def __init__(self, trailing_slash=True):
        self.trailing_slash = '/' if trailing_slash else ''
        super(SimpleRouter, self).__init__()

    def get_default_basename(self, viewset):
        """
        If `basename` is not specified, attempt to automatically determine
        it from the viewset.
        """
        queryset = getattr(viewset, 'queryset', None)

        assert queryset is not None, '`basename` argument not specified, and could ' \
            'not automatically determine the name from the viewset, as ' \
            'it does not have a `.queryset` attribute.'

        return queryset.model._meta.object_name.lower()

    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)]))
        extra_actions = viewset.get_extra_actions()

        # checking action names against the known actions list
        not_allowed = [
            action.__name__ for action in extra_actions
            if action.__name__ in known_actions
        ]
        if not_allowed:
            msg = ('Cannot use the @action decorator on the following '
                   'methods, as they are existing routes: %s')
            raise ImproperlyConfigured(msg % ', '.join(not_allowed))

        # partition detail and list actions
        detail_actions = [action for action in extra_actions if action.detail]
        list_actions = [action for action in extra_actions if not action.detail]

        routes = []
        for route in self.routes:
            if isinstance(route, DynamicRoute) and route.detail:
                routes += [self._get_dynamic_route(route, action) for action in detail_actions]
            elif isinstance(route, DynamicRoute) and not route.detail:
                routes += [self._get_dynamic_route(route, action) for action in list_actions]
            else:
                routes.append(route)

        return routes

    def _get_dynamic_route(self, route, action):
        initkwargs = route.initkwargs.copy()
        initkwargs.update(action.kwargs)

        url_path = escape_curly_brackets(action.url_path)

        return Route(
            url=route.url.replace('{url_path}', url_path),
            mapping=action.mapping,
            name=route.name.replace('{url_name}', action.url_name),
            detail=route.detail,
            initkwargs=initkwargs,
        )

    def get_method_map(self, viewset, method_map):
        """
        Given a viewset, and a mapping of http methods to actions,
        return a new mapping which only includes any mappings that
        are actually implemented by the viewset.
        """
        bound_methods = {}
        for method, action in method_map.items():
            if hasattr(viewset, action):
                bound_methods[method] = action
        return bound_methods

    def get_lookup_regex(self, viewset, lookup_prefix=''):
        """
        Given a viewset, return the portion of URL regex that is used
        to match against a single instance.

        Note that lookup_prefix is not used directly inside REST rest_framework
        itself, but is required in order to nicely support nested router
        implementations, such as drf-nested-routers.

        https://github.com/alanjds/drf-nested-routers
        """
        base_regex = '(?P<{lookup_prefix}{lookup_url_kwarg}>{lookup_value})'
        # Use `pk` as default field, unset set.  Default regex should not
        # consume `.json` style suffixes and should break at '/' boundaries.
        lookup_field = getattr(viewset, 'lookup_field', 'pk')
        lookup_url_kwarg = getattr(viewset, 'lookup_url_kwarg', None) or lookup_field
        lookup_value = getattr(viewset, 'lookup_value_regex', '[^/.]+')
        return base_regex.format(
            lookup_prefix=lookup_prefix,
            lookup_url_kwarg=lookup_url_kwarg,
            lookup_value=lookup_value
        )

    def get_urls(self):
        """
        Use the registered viewsets to generate a list of URL patterns.
        """
        ret = []

        for prefix, viewset, basename in self.registry:
            lookup = self.get_lookup_regex(viewset)
            routes = self.get_routes(viewset)

            for route in routes:

                # Only actions which actually exist on the viewset will be bound
                mapping = self.get_method_map(viewset, route.mapping)
                if not mapping:
                    continue

                # Build the url pattern
                regex = route.url.format(
                    prefix=prefix,
                    lookup=lookup,
                    trailing_slash=self.trailing_slash
                )

                # If there is no prefix, the first part of the url is probably
                #   controlled by project's urls.py and the router is in an app,
                #   so a slash in the beginning will (A) cause Django to give
                #   warnings and (B) generate URLS that will require using '//'.
                if not prefix and regex[:2] == '^/':
                    regex = '^' + regex[2:]

                initkwargs = route.initkwargs.copy()
                initkwargs.update({
                    'basename': basename,
                    'detail': route.detail,
                })

                view = viewset.as_view(mapping, **initkwargs)
                name = route.name.format(basename=basename)
                ret.append(url(regex, view, name=name))

        return ret

SimpleRouter