带MongoDB的Flask服务器（flask-pymongo）

Question

I'm trying to set up a flask server which adds data/users to a mongoDB database. I set up the DB (using mongo shell) like so:

>use dbname
switched to dbname    
>db.users.save( {username:"user", password:"pass"} )
WriteResult({ "nInserted" : 1 })

And confirm the data is written with db.users.find().

I added a mongo user like so:

>use admin
switched to db admin
>var w = { user:"user", roles:["readWriteAnyDatabase"], pwd:"password"}
>db.createUser(w)

My config.py looks like:

...
MONGO_URI = 'mongodb://user:password@localhost:27017/dbname'

and my python looks like this:

from flask import render_template, flash, redirect, Flask
from app import app
from flask_pymongo import PyMongo
from .forms import LoginForm

appp = Flask(__name__)
mongo = PyMongo(appp)

@app.route('/login', methods=['GET', 'POST'])
def login:
    form = LoginForm()
    if form.validate_on_submit():
        user = {"username": form.username.data,
                "password": form.password.data}
        post_id = mongo.db.users.insert_one(user)
        flash('Login req: u=%s, p=%s' % (form.username.data, str(form.remember_me.data)))
        return redirect('/index')

I thought all was well but I got this when I tried it out:

It appears to say something about the config_prefix? The docs say config_prefix is set to 'MONGO' by default and in my config the prefix is mongo. I must be missing something SOS

Answer 1

Kostas was correct.

I changed:

appp = Flask(__name__)
mongo = PyMongo(appp)

to simply

mongo = PyMongo(app)

Answer 2

You have a typo in

@app.route('/login', methods=['GET', 'POST'])

PyMongo uses current_app variable from flask which refers to the application instance handling the request. In this case app handles the request but appp has the configuration. So this line should become

@appp.route('/login', methods=['GET', 'POST'])