如何在 Flask 中使用 MongoDB？

Question

好的，所以我已经安装了 Flask，我想知道如何将 MongoDB 数据库与我即将开始构建的 Flask 应用程序连接和使用。

Answer 1

You can use any of these three libraries

• Flask-PyMongo - https://flask-pymongo.readthedocs.io/en/latest/
• Flask-MongoAlchemy - https://pythonhosted.org/Flask-MongoAlchemy/
• Flask-MongoEngine - http://docs.mongoengine.org/projects/flask-mongoengine/en/latest/

I personally use flask mongoengine and every things work fine

Answer 2

I personally find the PyMongo library simple and easy to use.

You first need to import MongoClient and create a connection:

from pymongo import MongoClient
client = MongoClient()

Then get your db instance and collection (table):

db = client.my_database
collection = db.my_collection

You can then manipulate your data by working with JSON documents that hold your data. There is a complete example on their website.

Take a look at this tutorial on how to use PyMongo.

Answer 3

Maybe you don't have to use special libraries for Flask to connect to MongoDB.

Just treat Flask application as a normal Python program, and connect to MongoDB via normal Python libraries like PyMongo .

Here 's an example by someone else. A Flask app connecting to MongoDB via PyMongo.

Answer 4

Here is the simple example of MongoDB with Flask

  import pymongo
  import json
  client = pymongo.MongoClient("localhost", 27017)
  collection_USER = client[simple]
  Define_Collection_for_USER_FILE = collection_USER['USER']
  Define_Collection_for_USER_FILE.remove({})
  Define_Collection_for_USER_FILE.insert(json.loads(filename))

Answer 5

There are multiple ways of using MongoDB with Flask - Flask_pymongo & flask_mongoengine are two python modules that can be used to for easy integration with mongoDB. both uses pymongo as the base libraries so the methods nd class available pymongo can be easily inherited while using any of the module (flask_pymongo and flask_mongoengine). I Found Using mongoengine Creating the Models are easier. I am providing the solution using flask_mongoengine.

using python 3.6 + and flask 1.1.1 + ( Tested with Python 3.7+ also )

Using flask_mongoengine

configuration-file.cfg

MONGODB_SETTINGS = {
    'DB': 'Your_DB_Name',
    'host': 'localhost',
    'port': 27017,
}

App.py file

app.config['SECRET_KEY'] = SECRET_KEY
db = MongoEngine()

app.config.from_pyfile('settings.cfg')

with app.app_context():
   db.init_app(app)
   try:
       db_client = db.connection['flask_webapp_db']
   except ConnectionFailure as e:
       sys.stderr.write("Could not connect to MongoDB: %s" % e)
       sys.exit(1)

........
@app.route('/')
def signup():
signup_form = get_signup_form(User)
if signup_form.validate_on_submit():
    try:
        user = db_client.User
        user.save(signup_form.data)
        print('user registered')
        return redirect('/')
    except WriteError as WE:
        print(WE)
return render_template('signup.html', form=signup_form)

create you User model in models file which should look like as below - this file is something which defines your tables ( known as Document in Mongodb )

models.py

from mongoengine.document import Document
from mongoengine.fields import DateTimeField, StringField, EmailField


class User(Document):
    username = StringField(min_length=4, required=True, unique=True)
    password = StringField(min_length=8, required=True)

    meta = {'db_alias': 'flask_webapp_db'}    # your db name where you want to create the table(Dcoument) User is your Document(Table) name
    def save(self, force_insert=False, validate=True, clean=True,
         write_concern=None, cascade=None, cascade_kwargs=None,
         _refs=None, save_condition=None, signal_kwargs=None, **kwargs):
        pass

Answer 6

I'm using Flask-Pymongo:

from pymongo import MongoClient

app = Flask(__name__)


app.config['MONGO_DBNAME'] = 'reports' # name of database on mongo
app.config["MONGO_URI"] = "mongodb://127.0.0.1:27017/reports"
mongo = PyMongo(app)

It's working!

Answer 7

There are a few steps that you have to follow. Since flask is a lighter framework you will need to install different packages to use according to your need.

So, since you will use Mongodb to work in your project you will have to install Pymongo .

pip install Pymongo

After that, you will need to set up your DB in MongoDB:

• So, in Mongodb create a database and then after your database is created within it create a collection or just add it from your function.

Database name: MyDaTaBaSe .

After it is done setup your work environment:

import os
from flask import Flask, render_template, redirect, request, url_for, session
from flask_pymongo import PyMongo #<<< THIS IS THE GUY YOU WILL NEED TO CONNECT WITH Mongodb



app = Flask(__name__)

#App configuration -- table name and the link
app.secret_key = 'any random string'
app.config['MONG_DBNAME'] = 'MyDaTaBaSe'
app.config['MONGO_URI'] = 'mongodb+srv://<YOUR_USERNAME_HERE>:<YOUR_PASSWORD_HERE>@myfirstcluster-uyvei.mongodb.net/MyDaTaBaSe?retryWrites=true'


mongo = PyMongo(app)

@app.route(/)
def index():
    return render_template('index.hml')

Therefore, the main guys are the app.config['MONG_DBNAME'] = 'MyDaTaBaSe' that you will need to tell which database you want to use and the app.config['MONGO_URI'] that you will need to set up your connection and link in which you will need to place your username and your password as well as the name of the database at the end.

So, this is the basics to connect with Mongodb.