Google App Engine数据存储上的Python API查询

Question

我在为Google App Engine上的Python查询获取正确响应方面遇到问题。

这是来自GAE的LOG，它成功地打印出与查询参数匹配的对象，但现在我试图将该对象数据作为JSON发回。我正在创建一个基本的用户认证系统，该系统使用电子邮件和密码查询USER对象，如果存在，则返回所有数据。

如何分解此查询以返回找到的数据？

E 00:21:06.352 Encountered unexpected error from ProtoRPC method implementation: AttributeError ('list' object has no attribute 'email') 
    Traceback (most recent call last): 
    File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/protorpc-1.0/protorpc/wsgi/service.py", line 181, in protorpc_service_app 
     response = method(instance, request) 
    File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/endpoints-1.0/endpoints/api_config.py", line 1332, in invoke_remote 
     return remote_method(service_instance, request) 
    File "/base/data/home/runtimes/python27/python27_lib/versions/third_party/protorpc-1.0/protorpc/remote.py", line 412, in invoke_remote_method 
     response = method(service_instance, request) 
    File "/base/data/home/apps/s~caramel-theory-800/1.381271940209425490/photoswap_api.py", line 34, in user_auth 
     return UserCreateResponseMessage(email=query.email, password=query.password, username=query.username, 
    AttributeError: 'list' object has no attribute 'email' 
E 00:21:06.360 [User(key=Key('User', 5086441721823232), email=u'pop', password=u'top', username=u'yop')] 

这里是端点API

我相信这个问题是代码的最后一行的地方改掉返回查询（UserAuthResponseMessage）的结果中..

@endpoints.method(UserAuthRequestMessage, UserAuthResponseMessage, 
        path='user', http_method='GET', 
        name='user.auth') 
def user_auth(self, request): 
    # create some type of query to check for email address, and than check to see if passwords match 
    query = User.query(User.email == request.email, User.password == request.password).fetch() 
    print query 

    # return the info from the server 
    return UserCreateResponseMessage(email=query[0].email, password=query[0].password, username=query[0].username, 
            id=query[0].key.id()) 


APPLICATION = endpoints.api_server([PhotoswapAPI], restricted=False) 

Answer 1

你的问题是你正在执行一个查询，并期望引用该查询的电子邮件属性，当然它没有。

如果您期望查询只有一个结果，那么您应该使用get而不是索引寻址。

另一个问题是user_auth包含的方法与您的堆栈跟踪不匹配。所以这里有一个问题。

Answer 2

在蒂姆霍夫曼的帮助下，这是我能够想出的解决方案。

我回来了错误的ResponseMessage，我最好使用.get而不是.fetch，因为应该只返回1个结果。

@endpoints.api(name='photoswap', version='v1') 
class PhotoswapAPI(remote.Service): 
    @endpoints.method(UserCreateRequestMessage, UserCreateResponseMessage, 
         path='user', http_method='POST', 
         name='user.create') 
    def user_create(self, request): 
     entity = User(email=request.email, password=request.password, username=request.username) 
     entity.put() 
     return UserCreateResponseMessage(email=entity.email, password=entity.password, username=entity.username, 
             id=entity.key.id()) 

    @endpoints.method(UserAuthRequestMessage, UserAuthResponseMessage, 
         path='user', http_method='GET', 
         name='user.auth') 
    def user_auth(self, request): 
     # create some type of query to check for email address, and than check to see if passwords match 
     query = User.query(User.email == request.email, User.password == request.password).get() 
     print query 

     # return the info from the server 
     return UserAuthResponseMessage(email=query.email, password=query.password, username=query.username, id=query.key.id()) 


APPLICATION = endpoints.api_server([PhotoswapAPI], restricted=False)