我在验证动态生成的WTForms SelectField时遇到问题。不知怎的，我的self.choices在POST期间是空的，而它们是在第一个GET请求中填充的。我是不是错过了什么？
app.py:
@app.route('/users/edit/<email>/', methods=['GET', 'POST'])
def users_edit(email):
match = False
for user in session['users']['message']:
if user['email']['S'] == email:
match = True
if match:
form = EditUserForm()
if request.method == 'GET':
form_data = session.get('edit_user_form_data', None)
if form_data:
form = EditUserForm(MultiDict(form_data))
form.shops_allowed.choices = [(str(shop['shop_id']['S']), str(shop['general']['M']['shop_name']['S'])) for i, shop in enumerate(session['shops']['message'])]
print(f"SHOPS_ALLOWED CHOICES WITH FORM DATA: {form.shops_allowed.choices}")
form.validate()
session.pop('edit_user_form_data', None)
else:
form.email.data = email
form.shops_allowed.choices = [(str(shop['shop_id']['S']), str(shop['general']['M']['shop_name']['S'])) for i, shop in enumerate(session['shops']['message'])]
print(f"SHOPS_ALLOWED CHOICES WITHOUT FORM DATA: {form.shops_allowed.choices}")
matched_shop = []
for user in session['users']['message']:
if user['email']['S'] == email and 'shops_allowed' in user.keys():
matched_shop = [allow['S'] for allow, shop in zip(user['shops_allowed']['L'], session['shops']['message'])]
form.shops_allowed.data = matched_shop
form.validate()
if request.method == 'POST' and form.validate_on_submit():
app.logger.info(f"PRE POST EDIT USER FORM DATA: {form.data}")
url = ...
<REDACTED POST REQUESTS ENDPOINT>
app.logger.info(f"POST EDIT USER RESPONSE: ({post_response.status_code}) {response_data}")
if post_response.status_code == 200:
session.pop('edit_user_form_data', None)
return redirect(url_for('users'))
else:
app.logger.info(f"EDIT USER FORM DATA: {form.data}")
session['edit_user_form_data'] = form.data
return redirect(url_for('users_edit', email=email))
elif request.method == 'POST' and form.validate_on_submit() == False:
app.logger.info(f"EDIT USER FORM DATA VALIDATION FAILED: {form.data}")
session['edit_user_form_data'] = form.data
return redirect(url_for('users_edit', email=email))
forms.py
class NonValidatingSelectMultipleField(SelectMultipleField):
def __len__(self):
return 1
def pre_validate(self, form):
pass
# HACK TO VALID A CHOICE FOR SELECT MULTIPLE
if self.data:
print(f"SELF DATA: {self.data}")
print(f"VALUES: {self.choices}")
values = list(self.coerce(c[0]) for c in self.choices)
print(f"PROCESSED VALUES: {values}")
for d in self.data:
if d not in values:
raise ValueError(self.gettext("'%(value)s' is not a valid choice for this multiple select field") % dict(value=d))
class EditUserForm(FlaskForm):
email = StringField('Email', [
validators.DataRequired(),
validators.Length(min=6),
validators.Email(message='Not a valid email address.')]
)
shops_allowed = NonValidatingSelectMultipleField(
'Shops',
widget = widgets.ListWidget(prefix_label=False),
option_widget = widgets.CheckboxInput(),
coerce=str
)
这将呈现以下日志记录：
SHOPS_ALLOWED CHOICES WITHOUT FORM DATA: [('decb5a00-fe45-484f-b887-b9bd41c4f0f2', 'My shop'), ('2cea2efa-7ccf-4bca-896d-16119d5fb7a8', 'My other shop')]
SELF DATA: ['decb5a00-fe45-484f-b887-b9bd41c4f0f2', '2cea2efa-7ccf-4bca-896d-16119d5fb7a8']
VALUES: [('decb5a00-fe45-484f-b887-b9bd41c4f0f2', 'My shop'), ('2cea2efa-7ccf-4bca-896d-16119d5fb7a8', 'My other shop')]
PROCESSED VALUES: ['decb5a00-fe45-484f-b887-b9bd41c4f0f2', '2cea2efa-7ccf-4bca-896d-16119d5fb7a8']
127.0.0.1 - - [03/Apr/2020 14:30:11] "GET /users/edit/my@email.com/ HTTP/1.1" 200 -
POST后：
SELF DATA: ['decb5a00-fe45-484f-b887-b9bd41c4f0f2', '2cea2efa-7ccf-4bca-896d-16119d5fb7a8']
VALUES: None
在屏幕上：
forms.py", line 35, in pre_validate values = list(self.coerce(c[0]) for c in self.choices) TypeError: 'NoneType' object is not iterable
Meh，在再次查看我的代码后，我终于发现了问题。我在验证if request.method == 'POST'的同时调用form.validate_on_submit()，这从未使我有可能在POST期间填充选项。
将我的代码更改为：
if request.method == 'POST':
form.shops_allowed.choices = [(str(shop['shop_id']['S']), str(shop['general']['M']['shop_name']['S'])) for i, shop in enumerate(session['shops']['message'])]
form.validate_on_submit()
它开始发挥作用。有时你只需要把事情写下来就可以看到答案：-(