WTForms：同一页面上的两个表单？

Question

我有一个动态网页，它应该处理两种表单：登录表单和注册表单。我正在使用 WTForms 来处理这两个表单，但我在使它工作时遇到了一些麻烦，因为这两个表单都被呈现到同一个页面。

以下是我网页登录表单的代码：

PYTHON:
class Login(Form):
    login_user = TextField('Username', [validators.Required()])
    login_pass = PasswordField('Password', [validators.Required()])

@application.route('/index', methods=('GET', 'POST'))
def index():
    l_form = Login(request.form, prefix="login-form")
    if request.method == 'POST' and l_form.validate():
        check_login = cursor.execute("SELECT * FROM users WHERE username = '%s' AND pwd = '%s'"
        % (l_form.login_user.data, hashlib.sha1(l_form.login_pass.data).hexdigest()))
        if check_login == True:
            conn.commit()
            return redirect(url_for('me'))
    return render_template('index.html', lform=l_form)


HTML:
<form name="lform" method="post" action="/index">
    {{ lform.login_user }}
    {{ lform.login_pass }}
    <input type="submit" value="Login" />
</form>

以下是我网页的注册表单的代码：

PYTHON:
class Register(Form):
    username = TextField('Username', [validators.Length(min=1, max = 12)])
    password = PasswordField('Password', [
        validators.Required(),
        validators.EqualTo('confirm_password', message='Passwords do not match')
    ])
    confirm_password = PasswordField('Confirm Password')
    email = TextField('Email', [validators.Length(min=6, max=35)])

@application.route('/index', methods=('GET','POST'))
def register():
    r_form = Register(request.form, prefix="register-form")
    if request.method == 'POST' and r_form.validate():
        check_reg = cursor.execute("SELECT * FROM users WHERE username = '%s' OR `e-mail` = '%s'"
        % (r_form.username.data, r_form.email.data))

        if check_reg == False:
            cursor.execute("INSERT into users (username, pwd, `e-mail`) VALUES ('%s','%s','%s')"
            % (r_form.username.data, hashlib.sha1(r_form.password.data).hexdigest(), check_email(r_form.email.data)))
            conn.commit()
            return redirect(url_for('index'))
    return render_template('index.html', rform=r_form)


HTML:
<form name="rform" method="post" action="/index">
    {{ rform.username }}
    {{ rform.email }}
    {{ rform.password }}
    {{ rform.confirm_password }}
    <input type="submit" value="Register />
</form>

继续加载网页时出现以下错误：

    Traceback (most recent call last):
  File "C:\Users\HTVal_000\Desktop\innoCMS\virtualenv\lib\site-packages\flask\app.py", line 1836, in __call__
    return self.wsgi_app(environ, start_response)
  File "C:\Users\HTVal_000\Desktop\innoCMS\virtualenv\lib\site-packages\flask\app.py", line 1820, in wsgi_app
    response = self.make_response(self.handle_exception(e))
  File "C:\Users\HTVal_000\Desktop\innoCMS\virtualenv\lib\site-packages\flask\app.py", line 1403, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "C:\Users\HTVal_000\Desktop\innoCMS\virtualenv\lib\site-packages\flask\app.py", line 1817, in wsgi_app
    response = self.full_dispatch_request()
  File "C:\Users\HTVal_000\Desktop\innoCMS\virtualenv\lib\site-packages\flask\app.py", line 1477, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "C:\Users\HTVal_000\Desktop\innoCMS\virtualenv\lib\site-packages\flask\app.py", line 1381, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "C:\Users\HTVal_000\Desktop\innoCMS\virtualenv\lib\site-packages\flask\app.py", line 1475, in full_dispatch_request
    rv = self.dispatch_request()
  File "C:\Users\HTVal_000\Desktop\innoCMS\virtualenv\lib\site-packages\flask\app.py", line 1461, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "C:\Users\HTVal_000\Desktop\innoCMS\main.py", line 36, in index
    return render_template('index.html', lform=l_form)
  File "C:\Users\HTVal_000\Desktop\innoCMS\virtualenv\lib\site-packages\flask\templating.py", line 128, in render_template
    context, ctx.app)
  File "C:\Users\HTVal_000\Desktop\innoCMS\virtualenv\lib\site-packages\flask\templating.py", line 110, in _render
    rv = template.render(context)
  File "C:\Users\HTVal_000\Desktop\innoCMS\virtualenv\lib\site-packages\jinja2\environment.py", line 969, in render
    return self.environment.handle_exception(exc_info, True)
  File "C:\Users\HTVal_000\Desktop\innoCMS\virtualenv\lib\site-packages\jinja2\environment.py", line 742, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "C:\Users\HTVal_000\Desktop\innoCMS\templates\default\index.html", line 52, in top-level template code
    {{ rform.username }}
  File "C:\Users\HTVal_000\Desktop\innoCMS\virtualenv\lib\site-packages\jinja2\environment.py", line 397, in getattr
    return getattr(obj, attribute)
UndefinedError: 'rform' is undefined

据我了解，表单之间存在冲突，因为根据回溯：

return render_template('index.html', lform=l_form)

返回以下错误：

UndefinedError: 'rform' is undefined

当脚本看到时：

{{ rform.username }}
{{ rform.email }}
{{ rform.password }}
{{ rform.confirm_password }}

但它完全忽略了：

{{ lform.login_user }}
{{ lform.login_pass }}

这可能有点混乱，我也很困惑，我希望有人以前遇到过这个问题，以便我也可以解决它。

Answer 1

这有点令人困惑，因为您在 index() 和 register() 上渲染 index.html，并且都注册了相同的路由 (@application.route('/index'))。当您将表单提交给/index 时，只有其中一个会被调用。你可以

• 将所有逻辑放在一个索引函数中，看看哪种形式（如果有）是有效的。
• 分开你的逻辑，只提交相关的表单

通常，您希望将逻辑分开，即使您希望在同一页面上同时显示登录和注册。所以我会试着向你展示正确的方向:-)

例如，首先将您的登录视图和注册视图分开，现在只检查与它们相关的表单的逻辑：

class Login(Form):
    login_user = TextField('Username', [validators.Required()])
    login_pass = PasswordField('Password', [validators.Required()])

class Register(Form):
    username = TextField('Username', [validators.Length(min=1, max = 12)])
    password = PasswordField('Password', [
        validators.Required(),
        validators.EqualTo('confirm_password', message='Passwords do not match')
    ])
    confirm_password = PasswordField('Confirm Password')
    email = TextField('Email', [validators.Length(min=6, max=35)])

@application.route('/login', methods=['POST'])
def index():
    l_form = Login(request.form, prefix="login-form")
    if l_form.validate():
        check_login = cursor.execute("SELECT * FROM users WHERE username = '%s' AND pwd = '%s'"
            % (l_form.login_user.data, hashlib.sha1(l_form.login_pass.data).hexdigest()))
        if check_login == True:
            conn.commit()
            return redirect(url_for('me'))
    return render_template('index.html', lform=l_form, rform=Register())

@application.route('/register', methods=['POST'])
def register():
    r_form = Register(request.form, prefix="register-form")
    if r_form.validate():
        check_reg = cursor.execute("SELECT * FROM users WHERE username = '%s' OR `e-mail` = '%s'"
            % (r_form.username.data, r_form.email.data))

        if check_reg == False:
            cursor.execute("INSERT into users (username, pwd, `e-mail`) VALUES ('%s','%s','%s')"
                % (r_form.username.data, hashlib.sha1(r_form.password.data).hexdigest(), check_email(r_form.email.data)))
            conn.commit()
            return redirect(url_for('index'))
    return render_template('index.html', lform=Login(), rform=r_form)

@application.route('/index')
def index():
    # If user is logged in, show useful information here, otherwise show login and register
    return render_template('index.html', lform=Login(), rform=Register())

然后，创建一个 index.html 来显示这两个表单并将它们发送到正确的方向。

<form name="lform" method="post" action="{{ url_for('login') }}">
    {{ lform.login_user }}
    {{ lform.login_pass }}
    <input type="submit" value="Login" />
</form>

<form name="rform" method="post" action="{{ url_for('register') }}">
    {{ rform.username }}
    {{ rform.email }}
    {{ rform.password }}
    {{ rform.confirm_password }}
    <input type="submit" value="Register" />
</form>

该代码未经测试，因此可能存在错误，但我希望它能让您朝着正确的方向前进。请注意，我们在所有对 render('index.html', ...) 的调用中都传递了 lform 和 rform。

更简单的改进/重构方法：使用函数来检查现有用户（您的 SELECT 语句）并为模板中的各个表单使用 Jinja2 的包含或宏。