Python 如何在scrapy crawler中使用用户名/密码进行身份验证？

我想在scrapy crawler中使用用户名/密码对Pymongo客户端进行身份验证。使用了此方法，但出现错误

   class MongoDBPipeline(object):
        def __init__(self):
            connection = pymongo.MongoClient(settings['MONGODB_HOST'], settings['MONGODB_PORT'])
            connection.the_database.authenticate(settings['MONGODB_USERNAME'],settings['MONGODB_PASSWORD'],source='$external', mechanism='PLAIN')
            db = connection[settings['MONGODB_DATABASE']]
            self.collection = db[settings['MONGODB_COLLECTION']]

错误：

 connection.the_database.authenticate(settings['MONGODB_USERNAME'],settings['MONGODB_PASSWORD'],source='$external', mechanism='PLAIN')
  File "/home/nikhil/.local/lib/python2.7/site-packages/pymongo/database.py", line 988, in authenticate
    connect=True)
  File "/home/nikhil/.local/lib/python2.7/site-packages/pymongo/mongo_client.py", line 397, in _cache_credentials
    sock_info.authenticate(credentials)
  File "/home/nikhil/.local/lib/python2.7/site-packages/pymongo/pool.py", line 287, in authenticate
    auth.authenticate(credentials, self)
  File "/home/nikhil/.local/lib/python2.7/site-packages/pymongo/auth.py", line 407, in authenticate
    auth_func(credentials, sock_info)
  File "/home/nikhil/.local/lib/python2.7/site-packages/pymongo/auth.py", line 329, in _authenticate_plain
    sock_info.command(source, cmd)
  File "/home/nikhil/.local/lib/python2.7/site-packages/pymongo/pool.py", line 184, in command
    codec_options, check, allowable_errors)
  File "/home/nikhil/.local/lib/python2.7/site-packages/pymongo/network.py", line 54, in command
    helpers._check_command_response(response_doc, msg, allowable_errors)
  File "/home/nikhil/.local/lib/python2.7/site-packages/pymongo/helpers.py", line 188, in _check_command_response
    raise OperationFailure(msg % errmsg, code, response)
pymongo.errors.OperationFailure: command SON([('saslStart', 1), ('mechanism', 'PLAIN'), ('payload', Binary('\x00nikhil\x00password', 0)), ('autoAuthorize', 1)]) on namespace $external.$cmd failed: no such cmd: saslStart

我想验证我的代码以将其写入mongodb

connection = pymongo.MongoClient("mongodb://localhost")

用户名和密码放在哪里？

很容易使用

但是，在正常情况下，您需要引用mongodb的python文档

--参考文献--

支持用户名和密码中的特殊字符

如果您的用户名或密码包含特殊字符（例如“/”、“”、或“@”），则必须对其进行%xx转义，以便在MongoDB URI中使用。PyMongo使用unquote_plus（）对其进行解码。例如：

MongoClient('mongodb://user:' + password + '@127.0.0.1')

你看过了吗？您确定PyMongo中使用的身份验证方法与数据库设置相同吗？