AttributeError：“str”对象没有属性“before_request”

Question

我是 Google 自然语言处理库的新手...并尝试从本地文本文件中获取实体，但不断出现错误。我什至尝试过 Google 的示例代码，但错误是相同的。

这是我的代码：

import six
from google.cloud import language
from google.cloud.language import enums
from google.cloud.language import types



def entities_text(text):
    """Detects entities in the text."""
    client = language.LanguageServiceClient(credentials='cred.json')

    if isinstance(text, six.binary_type):
        text = text.decode('utf-8')

    # Instantiates a plain text document.
    document = types.Document(
        content=text,
        type=enums.Document.Type.PLAIN_TEXT)

    # Detects entities in the document. You can also analyze HTML 
    with:
    #   document.type == enums.Document.Type.HTML
    entities = client.analyze_entities(document).entities

    # entity types from enums.Entity.Type
    entity_type = ('UNKNOWN', 'PERSON', 'LOCATION', 'ORGANIZATION',
               'EVENT', 'WORK_OF_ART', 'CONSUMER_GOOD', 'OTHER')

    for entity in entities:
        print('=' * 20)
        print(u'{:<16}: {}'.format('name', entity.name))
        print(u'{:<16}: {}'.format('type', entity_type[entity.type]))
        print(u'{:<16}: {}'.format('metadata', entity.metadata))
        print(u'{:<16}: {}'.format('salience', entity.salience))
        print(u'{:<16}: {}'.format('wikipedia_url',
            entity.metadata.get('wikipedia_url', '-')))



if __name__ == "__main__":
    with open('test.txt', 'r') as text:
        text = text.read()
    ent = entities_text(text)
    print(ent)

这是堆栈跟踪：

AuthMetadataPluginCallback " 
<google.auth.transport.grpc.AuthMetadataPlugin object at 
0x7f6973b4a668>" raised exception!
Traceback (most recent call last):
File "/home/user/Documents/CODE/venv/lib/python3.6/site- 
packages/grpc/_plugin_wrapping.py", line 79, in __call__
   callback_state, callback))
File "/home/user/Documents/CODE/venv/lib/python3.6/site- 
   packages/google/auth/transport/grpc.py", line 77, in __call__
   callback(self._get_authorization_headers(context), None)
File "/home/user/Documents/CODE/venv/lib/python3.6/site- 
   packages/google/auth/transport/grpc.py", line 61, in 
   _get_authorization_headers
   self._credentials.before_request(
AttributeError: 'str' object has no attribute 'before_request'

请问如何才能返回实体？

Answer 1

该credentials参数不接受 str，而是接受Credentials对象。从您的 JSON 文件创建一个并将其传入。

from google.oauth2 import service_account

credentials = service_account.Credentials.from_service_account_file(
'cred.json')

从这个文档页面

这里的提示是这一行：self._credentials.before_request。您传入credentials，该LanguageServiceClient对象将其放入私有变量中_credentials并尝试调用它的方法。由于您的字符串没有该方法，因此它会爆炸。