在多个字段上使用UniqueConstraint，它工作正常，但我想覆盖错误消息。
已经浏览了许多帖子，其中一些已经过时了，似乎没有一个指定如何覆盖此特定实例。(完整性错误)
字段为"用户"和"技能组"。我希望错误消息简单地说"技能组已在使用中"。它当前显示为"具有此用户的技能组和技能组已存在"。谢谢。
更新：认为我应该发布相关代码：
models.py
class SkillGroup(models.Model):
user = models.ForeignKey(User, on_delete=models.CASCADE)
skill_group = models.CharField(max_length=35)
sequence = models.IntegerField(default=999)
class Meta:
constraints = [
models.UniqueConstraint(fields=['user', 'skill_group'], name='unique_skillgroup'),
]
def __str__(self):
return self.skill_group
def get_absolute_url(self):
return reverse('skillgroup-list')
forms.py
class SkillGroupForm(forms.ModelForm):
class Meta:
model = SkillGroup
fields = ('user', 'skill_group')
widgets = {
'user': forms.HiddenInput,
}
views.py
class SkillGroupCreateView(LoginRequiredMixin, CreateView):
model = SkillGroup
form_class = SkillGroupForm
def get_initial(self):
return {'user': self.request.user}
def form_valid(self, form):
try:
result = super().form_valid(form)
except IntegrityError as err:
if str(err) == "Skill group with this User and Skill group already exists.":
raise IntegrityError("Skill Group already in use.")
raise
else:
return result
IntegrityError at /skillgroup/create/
duplicate key value violates unique constraint "unique_skillgroup"
DETAIL: Key (user_id, skill_group)=(1, Quality Assurance) already exists.
Request Method: POST
Request URL: http://localhost:8000/skillgroup/create/
Django Version: 2.2
Exception Type: IntegrityError
Exception Value:
duplicate key value violates unique constraint "unique_skillgroup"
DETAIL: Key (user_id, skill_group)=(1, Quality Assurance) already exists.
Exception Location: C:UsersCHRIST~1Envsbcslibsite-packagesdjangodbbackendsutils.py in _execute, line 84
Python Executable: C:UsersCHRIST~1EnvsbcsScriptspython.exe
Python Version: 3.7.2
Python Path:
['C:\Users\Christopher George\bcs\basicrecruiter',
'C:\Users\CHRIST~1\Envs\bcs\Scripts\python37.zip',
'C:\Users\CHRIST~1\Envs\bcs\DLLs',
'C:\Users\CHRIST~1\Envs\bcs\lib',
'C:\Users\CHRIST~1\Envs\bcs\Scripts',
'c:\users\christopher '
'george\appdata\local\programs\python\python37-32\Lib',
'c:\users\christopher '
'george\appdata\local\programs\python\python37-32\DLLs',
'C:\Users\CHRIST~1\Envs\bcs',
'C:\Users\CHRIST~1\Envs\bcs\lib\site-packages']
Server time: Thu, 18 Apr 2019 02:53:51 +0000
Traceback:
Environment:
Request Method: POST
Request URL: http://localhost:8000/skillgroup/create/
Django Version: 2.2
Python Version: 3.7.2
Installed Applications:
['recruiter.apps.RecruiterConfig',
'crispy_forms',
'phone_field',
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.common.CommonMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware']
Traceback:
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangodbbackendsutils.py" in _execute
84. return self.cursor.execute(sql, params)
The above exception (duplicate key value violates unique constraint "unique_skillgroup"
DETAIL: Key (user_id, skill_group)=(1, Quality Assurance) already exists.
) was the direct cause of the following exception:
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangocorehandlersexception.py" in inner
34. response = get_response(request)
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangocorehandlersbase.py" in _get_response
115. response = self.process_exception_by_middleware(e, request)
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangocorehandlersbase.py" in _get_response
113. response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangoviewsgenericbase.py" in view
71. return self.dispatch(request, *args, **kwargs)
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangocontribauthmixins.py" in dispatch
52. return super().dispatch(request, *args, **kwargs)
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangoviewsgenericbase.py" in dispatch
97. return handler(request, *args, **kwargs)
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangoviewsgenericedit.py" in post
172. return super().post(request, *args, **kwargs)
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangoviewsgenericedit.py" in post
142. return self.form_valid(form)
File "C:UsersChristopher Georgebcsbasicrecruiterrecruiterviews.py" in form_valid
104. return super().form_valid(form)
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangoviewsgenericedit.py" in form_valid
125. self.object = form.save()
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangoformsmodels.py" in save
458. self.instance.save()
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangodbmodelsbase.py" in save
741. force_update=force_update, update_fields=update_fields)
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangodbmodelsbase.py" in save_base
779. force_update, using, update_fields,
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangodbmodelsbase.py" in _save_table
870. result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangodbmodelsbase.py" in _do_insert
908. using=using, raw=raw)
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangodbmodelsmanager.py" in manager_method
82. return getattr(self.get_queryset(), name)(*args, **kwargs)
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangodbmodelsquery.py" in _insert
1186. return query.get_compiler(using=using).execute_sql(return_id)
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangodbmodelssqlcompiler.py" in execute_sql
1332. cursor.execute(sql, params)
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangodbbackendsutils.py" in execute
99. return super().execute(sql, params)
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangodbbackendsutils.py" in execute
67. return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangodbbackendsutils.py" in _execute_with_wrappers
76. return executor(sql, params, many, context)
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangodbbackendsutils.py" in _execute
84. return self.cursor.execute(sql, params)
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangodbutils.py" in __exit__
89. raise dj_exc_value.with_traceback(traceback) from exc_value
File "C:UsersCHRIST~1Envsbcslibsite-packagesdjangodbbackendsutils.py" in _execute
84. return self.cursor.execute(sql, params)
Exception Type: IntegrityError at /skillgroup/create/
Exception Value: duplicate key value violates unique constraint "unique_skillgroup"
DETAIL: Key (user_id, skill_group)=(1, Quality Assurance) already exists.
更新 2：根据 Django 文档中的一些阅读，我尝试将其更改为没有成功：
def save(self, *args, **kwargs):
try:
result = super().save(*args, **kwargs)
except IntegrityError as err:
if str(err) == "Skill group with this User and Skill group already exists.":
raise IntegrityError("Skill Group already in use.")
raise
else:
return result
默认情况下，在 Django 4.1 之前，没有自定义错误消息的默认方法。 Django 4.1 现在包含一个自定义错误消息的violation_error_message属性。
BaseConstraint.violation_error_message 在模型验证期间引发验证错误时使用的错误消息。 默认值为"违反约束"%(名称)"。 姜戈文档
对于您使用 Django 的情况 =>4.1
class Meta:
constraints = [
models.UniqueConstraint(fields=['user', 'skill_group'], name='unique_skillgroup', violation_error_message='your_error_message'),
]
您可以捕获异常并使用自定义消息重新引发它：
try:
# This is the statement that raises the exception
except IntegrityError as err:
if str(err) == "Skill group with this User and Skill group already exists.":
raise IntegrityError("Skill Group already in use.")
# Propagate the exception if the condition is not matched.
raise
更新
CreateView继承(除其他外)形式ModelFormMixin
form_valid(窗体)
保存窗体实例，设置视图的当前对象，并重定向到 get_success_url()。
因此，您可以：
class YourView(CreateView):
def form_valid(self, form):
try:
result = super().form_valid(form)
except IntegrityError as err:
if str(err) == "Skill group with this User and Skill group already exists.":
raise IntegrityError("Skill Group already in use.")
# Propagate exception is candition is not matched.
raise
else:
return result
更新2
也许您可以改为将该代码放在窗体的保存方法中。
class SkillGroupForm(forms.ModelForm):
# ...
def save(**kwargs):
try:
result = super().save(**kwargs)
except IntegrityError as err:
if str(err) == "Skill group with this User and Skill group already exists.":
raise IntegrityError("Skill Group already in use.")
raise
else:
return result
更新3：回答@Hamidreza的评论：
无论如何，这都会引发原始错误！ 因为您正在引发另一个错误，就在异常处理部分！所以它将显示原始错误和覆盖错误！说"在处理上述异常期间，发生了另一个异常">
当然，如果您查看堆栈跟踪，您将看到您指出的两个异常。但。。。 仅当您不处理异常时，才会发生这种情况。
这里的重点是OP想要更改它传播的错误消息，为此，解决方案已经足够好了。例如：
def foo():
try:
1 / 0
except ZeroDivisionError:
raise ZeroDivisionError("My very own error message")
try:
foo()
except ZeroDivisionError as err:
print(err) # Prints: "My very own error message"
所以：
try:
form.valid_form()
except IntegrityError as err:
# Here err will contains the error the OP wants if it is the case.
我在 Django 中遇到了类似的问题，我用这个解决方案解决了它：1)捕获错误 2)更改错误消息并 3)提出它：
def save(self, *args, **kwargs):
try:
result = super().save(*args, **kwargs)
except IntegrityError as err:
if str(err) == "Skill group with this User and Skill group already exists.":
err.agrs = ("Skill Group already in use.",) # You can add '+ err.args[1:]' at the end of this line but for more assurance, you can check the content of args and be sure that you are not missing anything here!
raise
else:
return result
请记住，err.args是一个元组。