我想避免使用样板代码为我的 Google App Engine 应用程序的不同模型创建 Google Cloud Endpoints API。假设我有一个 Post、User 和 Category 模型。数据存储在数据存储中。我想使用资源 posts、users 和 categories 创建一个 REST API。我为 posts 资源编写了以下代码:
import endpoints
from protorpc import messages
from protorpc import message_types
from protorpc import remote
from blog.models import Post
from cloud_endpoints import WEB_CLIENT_ID, ANDROID_CLIENT_ID, IOS_CLIENT_ID, ANDROID_AUDIENCE
class PostMessage(messages.Message):
id = messages.StringField(1)
title = messages.StringField(2)
body = messages.StringField(3)
class PostMessageCollection(messages.Message):
post_messages = messages.MessageField(PostMessage, 1, repeated=True)
def post_to_message(post):
return PostMessage(
id=str(post.key()),
title=post.title,
body=post.body)
ID_RESOURCE = endpoints.ResourceContainer(
message_types.VoidMessage,
id=messages.StringField(1, variant=messages.Variant.STRING))
PUT_RESOURCE = endpoints.ResourceContainer(
PostMessage,
id=messages.StringField(1, variant=messages.Variant.STRING))
POST_RESOURCE = endpoints.ResourceContainer(Post)
@endpoints.api(name='posts',
version='v1',
allowed_client_ids=[WEB_CLIENT_ID, ANDROID_CLIENT_ID, IOS_CLIENT_ID],
audiences=[ANDROID_AUDIENCE])
class PostsApi(remote.Service):
"""List"""
@endpoints.method(message_types.VoidMessage,
PostMessageCollection,
path='/posts',
http_method='GET',
name='posts.listPosts')
def list(self, unused_request):
post_messages = []
for post in Post.all():
post_messages.append(post_to_message(post))
return PostCollection(post_messages=post_messages)
"""Get"""
@endpoints.method(ID_RESOURCE,
PostMessage,
path='/posts/{id}',
http_method='GET',
name='posts.getPost')
def get(self, request):
try:
return post_to_message(Post.get(request.id))
except (IndexError, TypeError):
raise endpoints.NotFoundException('Post %s not found.' % (request.id,))
"""Create"""
@endpoints.method(POST_RESOURCE,
message_types.VoidMessage,
path='/posts',
http_method='POST',
name='posts.createPost')
def create(self, request):
post = Post(title=request.title, body=request.body)\
post.put()
return message_types.VoidMessage()
"""Update"""
@endpoints.method(PUT_RESOURCE,
message_types.VoidMessage,
path='/posts/{id}',
http_method='POST',
name='posts.updatePost')
def update(self, request):
try:
post = Post.get(request.id)
post.title = request.title
post.body = request.body
return message_types.VoidMessage()
except (IndexError, TypeError):
raise endpoints.NotFoundException('Post %s not found.' % (request.id,))
"""Delete"""
@endpoints.method(ID_RESOURCE,
message_types.VoidMessage,
path='/posts/{id}',
http_method='DELETE',
name='posts.deletePost')
def delete(self, request):
try:
post = Post.get(request.id)
post.delete()
return message_types.VoidMessage()
except (IndexError, TypeError):
raise endpoints.NotFoundException('Post %s not found.' % (request.id,))
我可以复制/粘贴此代码并将“Post”更改为“Category”，然后编辑 PostMessage、PostMessageCollection 和 post_to_message，但这似乎是不好的做法。我不想重复自己。是否可以创建抽象 API 类并为 PostAPI、CategoryAPI 和 UserAPI 创建子类？或者是否有更好的方法来参数化 Post、PostMessage、PostMessageCollection、post_to_message 和资源路径 ( “/posts”、“/categories”和“/users”)这样我就不必为每个资源复制/粘贴类？这些类将具有相同的方法和相同的装饰器，我不想对每个资源重复这一点。我使用 Python 2.7。
请您参考如下方法:
我也偶然发现了同样的问题，不幸的是，这对于 google 云端点 是不可能的。方法装饰器需要请求描述(此处为 PostMessageCollection)。 message.Message 子类的请求描述不允许通过继承重用，因此所有消息类都必须完全定义，没有任何继承。
然而，您可以通过以下方式在某种程度上实现这一点(虽然我还没有测试过，但现在想到了 :)):
# All the message and response definitions have to be here, complete.
class PostMessage(messages.Message):
id = messages.StringField(1)
title = messages.StringField(2)
body = messages.StringField(3)
class PostMessageCollection(messages.Message):
post_messages = messages.MessageField(PostMessage, 1, repeated=True)
def post_to_message(post):
return PostMessage(
id=str(post.key()),
title=post.title,
body=post.body)
ID_RESOURCE = endpoints.ResourceContainer(
message_types.VoidMessage,
id=messages.StringField(1, variant=messages.Variant.STRING))
PUT_RESOURCE = endpoints.ResourceContainer(
PostMessage,
id=messages.StringField(1, variant=messages.Variant.STRING))
POST_RESOURCE = endpoints.ResourceContainer(Post)
# Now define all the 'Category' related messages here.
@endpoints.api(name='posts_n_categories', # The name can be a common one.
version='v1',
allowed_client_ids=[WEB_CLIENT_ID, ANDROID_CLIENT_ID, IOS_CLIENT_ID],
audiences=[ANDROID_AUDIENCE])
class BaseAPI(remote.Service):
"""List"""
# Common defs go here.
MessageCollection = messages.Message
PATH = '/'
NAME = ''
@staticmethod
def converter(x):
raise NotImplemented
iterator = []
collection = messages.Message
@endpoints.method(message_types.VoidMessage,
MessageCollection,
path=PATH,
http_method='GET',
name=NAME)
def list(self, unused_request):
# Do the common work here. You can
_messages = []
for post in self.__class__.iterator.all():
_messages.append(self.__class__.converter(post))
return self.__class__.collection(post_messages=_messages)
@endpoints.api(name='posts', # The name can be different.
version='v1',
allowed_client_ids=[WEB_CLIENT_ID, ANDROID_CLIENT_ID, IOS_CLIENT_ID],
audiences=[ANDROID_AUDIENCE])
class PostAPI(Base):
# Post specific defs go here.
MessageCollection = PostMessageCollection
PATH = '/posts'
NAME = 'posts.listPosts'
converter = post_to_message
iterator = Post
collection = PostCollection
# Define the category class here.
显然，它并没有节省多少时间。
