我需要连接两个数据库。默认数据库是固定的,但另一个是动态的,它基于URL。
例如,如果url是:yourapp.myweb.com,那么第二个数据库名称将是 yourapp
我尝试将数据库连接到 init .py,但它显示我的错误
builtins.AssertionError
AssertionError: A setup function was called after the first request was handled. This usually indicates a bug in the application where a module was not imported and decorators or other functionality was called too late.
To fix this make sure to import all your view modules, database models and everything related at a central place before the application starts serving requests.
这是我的 init .py
from flask import Flask,session
from flask_sqlalchemy import SQLAlchemy
import os
app = Flask(__name__,static_url_path='/static')
# Database Connection
database = request.url.split("/")[2].split(".")[0]
app.config['SQLALCHEMY_DATABASE_URI'] = "mysql+pymysql://root:root@localhost/main_database"
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = True
app.config['SQLALCHEMY_BINDS'] = {
'user_db': 'mysql+pymysql://root:root@localhost/database_'+str(database), #dynamic Connection
}
db = SQLAlchemy(app)
db.create_all()
db.create_all(bind=['user_db'])
# db.init_app(app)
from . import views
这是viwe.py
@app.route('/login', methods = ['GET'])
def index():
try:
from .model import Users
# Some Code
except Exception as e:
raise e
# return "Failed to login ! Please try again."
这是model.py
from application import db
class Users(db.Model):
__bind_key__ = 'user_db'
__tablename__ = 'users'
id = db.Column(db.Integer, primary_key = True)
email = db.Column(db.String(50))
name = db.Column(db.String(50))
password = db.Column(db.String())
def __repr__(self):
return '<User %r>' % self.name
答案 0 :(得分:3)
正如我在其中一条评论中所说,这可能是数据库连接的问题。这是我要检查的内容:
首先,确保在虚拟环境中安装了正确的引擎(您可以通过运行pip list
轻松检查;为了以防万一,让我坚持要求将库安装在virtual environment)。确保您没有pymysql
,而是Python3的端口,名为mysqlclient。 pymysql
仅适用于Python2。要安装此库,您需要先安装Python和MySQL开发头。例如,在Debian / Ubuntu中:
sudo apt-get install python-dev libmysqlclient-dev
然后您可以使用以下命令安装库:
pip install mysqlclient
如果已安装,请确保您可以使用库实际连接到数据库。在虚拟环境中打开Python shell并键入以下内容(来自github中的示例):
import pymysql.cursors
connection = pymysql.connect(host='<you_host>',
user='<user>',
password='<password>',
db='<database_name>',
charset='utf8mb4',
cursorclass=pymysql.cursors.DictCursor)
try:
with connection.cursor() as cursor:
do_something()
except:
pass
如果这样做,请确保您正在运行最新版本的Flask(0.12 at the moment;这可以通过运行pip list
再次检查),因为有几个错误与在DEBUG模式下运行Flask有关,已经修复了一段时间。
这肯定不是这种情况,但是另一个健全性检查是验证您要用于Flask的端口上没有运行其他进程。
如果以上所有方法都正常工作,我需要看一下堆栈跟踪以找出实际发生的情况。