蓝图,Flask中的PyMongo

Question

在我的蓝图中拾取我的mongo对象的正确方法是什么？

这是我如何拥有我的父母login.py:

app.config.from_object('config')
from flask.ext.pymongo import PyMongo
from child import child
from child2 import child2


app = Flask(__name__)
app.register_blueprint(child2.child2)
app.register_blueprint(child.child)

在我的 child.py

from app import app
from flask.ext.pymongo import PyMongo

mongo = PyMongo(app)
child = Blueprint('child', __name__)

child2.py 与孩子的结构相同:

from app import app
from flask.ext.pymongo import PyMongo

mongo = PyMongo(app)
child2 = Blueprint('child2', __name__)

这是错误消息:

raise Exception('duplicate config_prefix "%s"' % config_prefix)
Exception: duplicate config_prefix "MONGO"

我在蓝图中尝试了以下内容

mongo = app.data.driver

但这给了:

AttributeError: 'Flask' object has no attribute 'data'

一旦我的应用创建了连接,我应该如何在我的蓝图中提取它？

这是完整的痕迹

Traceback (most recent call last):
  File "login.py", line 12, in <module>
    from child import child
  File "/home/xxx/xxx/child/child.py", line 13, in <module>
    mongo = PyMongo(app) #blueprint
  File "/home/xxx/xxx/lib/python3.4/site-packages/flask_pymongo/__init__.py", line 97, in __init__
    self.init_app(app, config_prefix)
  File "/home/xxx/xxx/lib/python3.4/site-packages/flask_pymongo/__init__.py", line 121, in init_app
    raise Exception('duplicate config_prefix "%s"' % config_prefix)
Exception: duplicate config_prefix "MONGO"
(xxx)xxx@linux:~/xxx$ python login.py 
Traceback (most recent call last):
  File "login.py", line 12, in <module>
    from courses import courses
  File "/home/xxx/xxx/child/child.py", line 13, in <module>
    mongo = PyMongo(app) #blueprint
  File "/home/xxx/xxx/lib/python3.4/site-packages/flask_pymongo/__init__.py", line 97, in __init__
    self.init_app(app, config_prefix)
  File "/home/xxx/xxx/lib/python3.4/site-packages/flask_pymongo/__init__.py", line 121, in init_app
    raise Exception('duplicate config_prefix "%s"' % config_prefix)
Exception: duplicate config_prefix "MONGO"

所以问题是如何在每个蓝图中构建连接字符串到db的结构.这是文件结构:

login.py
config.py
/child/child.py
/child2/child2.py

这里是 config.py

MONGO_DBNAME = 'xxx'

MONGO_URL = os.environ.get('MONGO_URL')
if not MONGO_URL:
    MONGO_URL = "mongodb://xxx:xxxx@xxxx.mongolab.com:55822/heroku_xxx";

MONGO_URI = MONGO_URL

我在答案中尝试了下面的建议,但这没有用.请参阅下面我的评论,预期答案.

Answer 1

正如Emanuel Ey所暗示的那样,在蓝图中执行导入方法的问题之一就是导致循环导入.经过多次播放后,事实证明,唯一的方法(我能找到)是创建一个database.py连接到数据库的单独文件然后我可以通过蓝图导入此连接,如下所示:

child.py

from database import mongo
courses = Blueprint('courses', __name__)

和我的 database.py

from flask.ext.pymongo import PyMongo
mongo = PyMongo() 

和app,login.py但必须初始化数据库

from database import mongo
app = Flask(__name__)
app.config.from_object('config')
mongo.init_app(app) # initialize here!

from child import child 
from child import2 child2

app.register_blueprint(child.child)
app.register_blueprint(child2.child2)