Flask Session报错的解决方法：RuntimeError: The session is unavailable because no secret key was set.

flask session在初始化时报错：RuntimeError: The session is unavailable because no secret key was set.  Set the secret_key on the application to something unique and secret.

from flask import Flask, session
from flask_session import Session
import os

app = Flask(__name__)
app.config['SECRET_KEY'] = os.urandom(24)
Session(app)

解决方法：增加app.config['SESSION_TYPE'] = 'filesystem'语句

from flask import Flask, session
from flask_session import Session
import os

app = Flask(__name__)
app.config['SESSION_TYPE'] = 'filesystem'
app.config['SECRET_KEY'] = os.urandom(24)
Session(app)