python - import pymongo 导致 `ImportError: cannot import name BSON` 。你如何修复导入错误？

Question

我无法使用 Flask、MongoDB 和 Python 让一个简单的 Hello World 应用程序工作。尝试从 bson 模块导入时，应用程序正在轰炸。所有模块都通过 pip 成功安装，并且我在 virtualenv 中运行，所以我不确定为什么会出现错误:ImportError: cannot导入名称 BSON

这是我的示例应用代码:

import os
from flask import Flask
from flask import g
from flask import jsonify
from flask import json
from flask import request
from flask import url_for
from flask import redirect
from flask import render_template
from flask import make_response
import pymongo
from pymongo import Connection
from bson import BSON
from bson import json_util

app = Flask(__name__)

@app.route('/')
def hello():

    connection = Connection()
    # Get your DB
    db = connection.my_database
    # Get your collection
    cars = db.cars
    # Create some objects
    import datetime
    car = {"brand": "Ford",
           "model": "Mustang",
           "date": datetime.datetime.utcnow()}
    # Insert it
    cars.insert(car)
    json_docs = [json.dumps(doc, default=json_util.default) for doc in cars.find()]

    return json_docs


if __name__ == '__main__':
    # Bind to PORT if defined, otherwise default to 5000.
    port = int(os.environ.get('PORT', 5000))
    app.debug = True
    app.run(host='0.0.0.0', port=port)

我不确定如何进行调试，或者这里是否缺少某些东西。

编辑:pip freeze的结果:

Flask==0.9
Jinja2==2.6
WTForms==1.0.2
Werkzeug==0.8.3
bson==0.3.3
distribute==0.6.28
mongo==0.2.0
pymongo==2.3
pytz==2012g
wsgiref==0.1.2

Edit2:删除 bson 和 pymongo，重新运行 pip install pymongo。现在完成跟踪:

Traceback (most recent call last):
18:21:20 web.1  |   File ".../venv/lib/python2.7/site-packages/flask/app.py", line 1701, in __call__
18:21:20 web.1  |     return self.wsgi_app(environ, start_response)
18:21:20 web.1  |   File ".../venv/lib/python2.7/site-packages/flask/app.py", line 1689, in wsgi_app
18:21:20 web.1  |     response = self.make_response(self.handle_exception(e))
18:21:20 web.1  |   File ".../venv/lib/python2.7/site-packages/flask/app.py", line 1687, in wsgi_app
18:21:20 web.1  |     response = self.full_dispatch_request()
18:21:20 web.1  |   File ".../venv/lib/python2.7/site-packages/flask/app.py", line 1361, in full_dispatch_request
18:21:20 web.1  |     response = self.make_response(rv)
18:21:20 web.1  |   File ".../venv/lib/python2.7/site-packages/flask/app.py", line 1450, in make_response
18:21:20 web.1  |     rv = self.response_class.force_type(rv, request.environ)
18:21:20 web.1  |   File ".../venv/lib/python2.7/site-packages/werkzeug/wrappers.py", line 711, in force_type
18:21:20 web.1  |     response = BaseResponse(*_run_wsgi_app(response, environ))
18:21:20 web.1  |   File ".../venv/lib/python2.7/site-packages/werkzeug/test.py", line 818, in run_wsgi_app
18:21:20 web.1  |     app_iter = app(environ, start_response)
18:21:20 web.1  | TypeError: 'list' object is not callable

Answer 1

尝试卸载 bson 和 pymongo 包，然后重新安装 pymongo 包。 pymongo 安装自己的 bson 包，我认为你已经用其他 bson 包安装覆盖了它，这可能是导致你导入的原因错误。

仅供引用:

• 当您 pip install pymongo 时，它也会安装 bson，但它不会打印一条消息说它正在将 bson 安装到您的 virtualenv 站点包中
• pymongo 也没有将 bson 列为 dep
• pip -v list 也没有显示 bson 已安装
• IMO 的那些要点有一些代码味道(至少打印一条消息，说明您正在安装 bson)