我正在构建一个测试网站来熟悉 Flask，我试图通过锚点将用户重定向到登录或注册页面，但是当我进入该页面时，我收到错误
jinja2.exceptions.UndefinedError: 'app' is undefined
这是 HTML：
<!DOCTYPE html>
<head>
<meta charset="utf-8">
<title>Armored Core 6: Fires of Rubicon</title>
<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.7.1/css/all.css">
<link href="../static/style.css" rel="stylesheet" type="text/css">
</head>
<body>
<div class="container">
<div class="logo">
<img src="../static/ac6img.jpg" height="140px" width="140px">
</div>
<div class="text"><h1 class="title">Armored Core 6: Fires of Rubicon Fan Page</h1></div>
<div class="registerbuttondiv"><a href="{{url_for(app.login)}}" ><h1>Register</h1></a></div>
<div class="loginbuttondiv"><button class="loginbutton" onclick="location.href = 'login.html';"><h1>Login</h1></button></div>
</div>
</body>
这是代码
from flask import url_for, Flask, render_template, request
app = Flask(__name__)
@app.route('/')
def index():
return render_template('index.html')
@app.route('/login', methods=['POST', 'GET'])
def login():
error = None
if request.method == 'POST':
if valid_login(request.form['username'],
request.form['password']):
return log_the_user_in(request.form['username'])
else:
error = 'Invalid username/password'
return render_template('login.html', error=error)
def valid_login(uname, pwd):
suname = "user"
spwd = "pwd"
if uname == suname and pwd == spwd:
return True
else:
return False
def log_the_user_in(uname):
return render_template('user.html')
这是回溯
File "/usr/local/lib/python3.12/site-packages/flask/app.py", line 1488, in __call__
return self.wsgi_app(environ, start_response)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/flask/app.py", line 1466, in wsgi_app
response = self.handle_exception(e)
^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/flask/app.py", line 1463, in wsgi_app
response = self.full_dispatch_request()
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/flask/app.py", line 872, in full_dispatch_request
rv = self.handle_user_exception(e)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/flask/app.py", line 870, in full_dispatch_request
rv = self.dispatch_request()
^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/flask/app.py", line 855, in dispatch_request
return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args) # type: ignore[no-any-return]
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/py/hello.py", line 13, in index
return render_template('index.html')
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/flask/templating.py", line 150, in render_template
return _render(app, template, context)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/flask/templating.py", line 131, in _render
rv = template.render(context)
^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/jinja2/environment.py", line 1301, in render
self.environment.handle_exception()
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/jinja2/environment.py", line 936, in handle_exception
raise rewrite_traceback_stack(source=source)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/py/templates/index.html", line 14, in top-level template code
<div class="registerbuttondiv"><a href="{{url_for(app.login)}}" ><h1>Register</h1></a></div>
File "/usr/local/lib/python3.12/site-packages/jinja2/environment.py", line 485, in getattr
return getattr(obj, attribute)
^^^^^^^^^^^^^^^^^^^^^^^
Jinja 假设 app 是一个你应该从你的路由传递给它的变量，应用程序对象不会自然地持久化到前端，因此
href="{{url_for(app.login)}}"apphref="{{url_for(‘login’)}}"