我正在尝试学习如何使用 Python 构建基本的 Flask 应用程序。我首先按照他们的优秀教程制作了一个简单的博客。本教程让您session从flask. 稍后将其设置为“登录”，并且只有在这种情况下，用户才能写帖子。例如登录功能如下：
@app.route('/login', methods=['GET', 'POST'])
def login():
error = None
if request.method == 'POST':
if request.form['username'] != app.config['USERNAME']:
error = 'Invalid username'
elif request.form['password'] != app.config['PASSWORD']:
error = 'Invalid password'
else:
session['logged_in'] = True
flash('You were logged in')
return redirect(url_for('show_entries'))
return render_template('login.html', error=error)
然后，另一个函数检查会话是否确实在“logged_in”上：
@app.route('/add', methods=['GET', 'POST'])
def add_entry():
if not session.get('logged_in'):
abort(401)
g.db.execute('insert into entries (title, text) values (?, ?)',
[request.form['title'], request.form['text']])
g.db.commit()
flash('New entry was successfully posted')
return redirect(url_for('show_entries'))
但是，当我尝试在我的应用程序中执行此操作时，我得到500 Internal Server Error:
内部服务器错误
服务器遇到内部错误，无法完成您的请求。服务器过载或应用程序出错。
我认为这是因为在教程中使用了 sqlite 数据库，而当我收到错误时我使用的是 Flask-SQLAlchemy。这可能是问题的根源吗？如果是，是否有推荐的方法来做类似的事情？即允许应用程序检查是否有人登录？
以下是我的完整代码：
from flask import Flask, request, session, redirect, url_for, render_template
from flask.ext.sqlalchemy import SQLAlchemy
app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:////tmp/z.db'
DEBUG = True
db = SQLAlchemy(app)
class User(db.Model):
id = db.Column(db.Integer, primary_key=True)
username = db.Column(db.String(80), unique=True)
email = db.Column(db.String(120), unique=True)
password = db.Column(db.String(160), unique=True)
def __init__(self, username, email, password):
self.username = username
self.email = email
self.password = password
def __repr__(self):
return '<User %r>' % self.username
@app.route('/', methods=['GET', 'POST'])
def home():
#check to see if logged in
if session['logged_in'] == True:
note = "this text is displayed because you are logged in."
note=None
if request.method == 'POST':
new_user = User(request.form['username'], request.form['email'], request.form['password'])
#before making the new user, check to make sure the entered information isn't already in the db
if User.query.filter_by(username=request.form['username']).first() != None:
note = "sorry, this username has already been taken"
elif User.query.filter_by(email=request.form['email']).first() != None :
note = "sorry, this email address is already associated with an account."
else:
db.session.add(new_user)
db.session.commit()
session['logged_in'] = True
redirect(url_for('home'))
return render_template('index.html', note=note)
@app.route('/login', methods=['GET', 'POST'])
def signin():
note=None
if request.method == 'POST':
#get username and search for it in db
tag = request.form['username']
#if the entry contains '@', search db as email address
if tag.find('@') != -1:
user = User.query.filter_by(email=tag).first()
else:
user = User.query.filter_by(username=tag).first()
#if user exists, get password associated with it
if user != None:
password = user.password
#see if db email equals email input in HTML
if password == request.form['password']:
session['logged_in'] = True
return redirect(url_for('home'))
else:
note='wrong password'
else:
#call an error message
note='this username does not seem to exist. that is all i know'
return render_template('login.html', note=note)
if __name__ == '__main__':
app.run()
提前谢谢了。