Mongodb 用于分页的pymngo和烧瓶

我想用Flask构建PythonWebService，它可以用Flask从mongo获取数据

我有一个问题：

db.item.find({},{"uid":1,"created_on":1,"attributes.value":1}).sort({created_on:-1}).limit(3).pretty()

输出：

{
    "_id" : ObjectId("5656f606a80ea9407853808b"),
    "uid" : 2008,
    "created_on" : ISODate("2015-11-26T05:14:07Z")
}
{
    "_id" : ObjectId("5656f5f9a80ea94076538098"),
    "uid" : 2007,
    "created_on" : ISODate("2015-11-26T05:12:29Z")
}
{
    "_id" : ObjectId("5656f5e7a80ea94076538097"),
    "uid" : 2006,
    "created_on" : ISODate("2015-11-26T05:12:20Z")
}
{
    "_id" : ObjectId("5656f5d6a80ea940775380c3"),
    "uid" : 2005,
    "created_on" : ISODate("2015-11-26T05:12:19Z")
}
{
    "_id" : ObjectId("5656f4c4a80ea94076538095"),
    "uid" : 2004,
    "created_on" : ISODate("2015-11-26T05:12:14Z")
}
{
    "_id" : ObjectId("5656f4b4a80ea940775380c2"),
    "uid" : 2003,
    "created_on" : ISODate("2015-11-26T05:12:09Z")
}
{
    "_id" : ObjectId("5656f4a7a80ea9407853808a"),
    "uid" : 2002,
    "created_on" : ISODate("2015-11-26T05:12:05Z")
}
{
    "_id" : ObjectId("5656f499a80ea940775380c1"),
    "uid" : 2001,
    "created_on" : ISODate("2015-11-26T05:12:00Z")
}
{
    "_id" : ObjectId("5656f483a80ea94078538089"),
    "uid" : 2000,
    "created_on" : ISODate("2015-11-26T05:11:55Z")
}
{
    "_id" : ObjectId("5656f462a80ea94078538088"),
    "uid" : 1999,
    "created_on" : ISODate("2015-11-26T05:11:51Z")
}
{
    "_id" : ObjectId("5656f454a80ea94075538089"),
    "uid" : 1998,
    "created_on" : ISODate("2015-11-26T05:11:46Z")
}
{
    "_id" : ObjectId("5656f42fa80ea940775380c0"),
    "uid" : 1997,
    "created_on" : ISODate("2015-11-26T05:11:42Z")
}
{
    "_id" : ObjectId("5656f404a80ea94076538094"),
    "uid" : 1996,
    "created_on" : ISODate("2015-11-26T05:11:37Z")
}
{
    "_id" : ObjectId("5656f3f7a80ea940775380bd"),
    "uid" : 1995,
    "created_on" : ISODate("2015-11-26T05:11:32Z")
}
{
    "_id" : ObjectId("5656f3d2a80ea94078538087"),
    "uid" : 1994,
    "created_on" : ISODate("2015-11-26T05:11:27Z")
}
{
    "_id" : ObjectId("5656f3bba80ea94076538093"),
    "uid" : 1993,
    "created_on" : ISODate("2015-11-26T05:11:22Z")
}
{
    "_id" : ObjectId("5656f363a80ea94078538086"),
    "uid" : 1992,
    "created_on" : ISODate("2015-11-26T05:11:17Z")
}
{
    "_id" : ObjectId("5656f351a80ea94076538092"),
    "uid" : 1991,
    "created_on" : ISODate("2015-11-26T05:11:13Z")
}
{
    "_id" : ObjectId("5656f327a80ea940775380bc"),
    "uid" : 1990,
    "created_on" : ISODate("2015-11-26T05:11:08Z")
}
{
    "_id" : ObjectId("5656f308a80ea94078538085"),
    "uid" : 1989,
    "created_on" : ISODate("2015-11-26T05:11:03Z")
}

我试过这个：

from flask import Flask
from flask.ext.pymongo import PyMongo

app = Flask(__name__)
mongo = PyMongo(app)


@app.route('/')
def home_page():
    online_items = mongo.db['mydb'].item.find({},{"uid":1}).sort({created_on:-1})
    return render_template('index.html',
        online_users=online_items)

if __name__ == '__main__':
    app.run()

但它给出了500个误差。有什么建议吗？还希望在其上添加分页

debug=True时出错

Traceback (most recent call last):
  File "/usr/lib/python2.7/runpy.py", line 162, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "/usr/lib/python2.7/runpy.py", line 72, in _run_code
    exec code in run_globals
  File "/usr/local/iep/iep-3.7/source/iep/__main__.py", line 46, in <module>
    import iep
  File "/usr/local/iep/iep-3.7/source/iep/__init__.py", line 56, in <module>
    raise RuntimeError('IEP requires Python 3.x to run.')
RuntimeError: IEP requires Python 3.x to run.

回溯（最近一次呼叫最后一次）：
文件“/usr/lib/python2.7/runpy.py”，第162行，在运行模块中作为主模块
“\uuuuu main\uuuuuuuuuuuuuuuuuuuuuuuuu”，fname，loader，pkg\u name）
文件“/usr/lib/python2.7/runpy.py”，第72行，在运行代码中
run_globals中的exec代码
文件“/usr/local/iep/iep-3.7/source/iep/______.py”，第46行，在
进口iep
文件“/usr/local/iep/iep-3.7/source/iep/_init__.py”，第56行，在
raise RUNTIMERROR（'IEP需要Python 3.x才能运行'）
RuntimeError:IEP需要Python3.x才能运行。

我发现您忘记导入

渲染模板了

将此行更改为：

from flask import Flask

到

如果仍然存在一些错误，请打开调试模式：

if __name__ == '__main__':
     app.run(debug=True)

并粘贴完整的错误日志。
谢谢@lord63.j。让我试试这个。这里debug=True要求我运行python 3。那么，有没有其他方法可以用Python2.7调试这个问题？我不知道这是什么意思？你能给我看完整的日志吗？为你更新的问题恐怕iep不支持python2.x，你可以看到“编程语言：：Python：：3”。因此，您可能必须使用python3.x来运行您的应用程序。非常感谢@lord64.J
if __name__ == '__main__':
     app.run(debug=True)