将kwargs传递到Django中的自定义字段

Question

我以这个问题作为创建自定义字段的基础：Django文件上传大小限制当我尝试进行迁移时，我收到一条错误消息，指出“ content_types”不在垃圾堆中。我已经调试了代码，几乎好像我的自定义字段init被调用了两次。一次是在我拥有此字段的模型中（带有kwarg），一次是不包含kwargs。我引用了这篇文章： 如何在Django Rest Framework的自定义字段中传递其他关键字参数？但是，无论解决方案怎么说，我已经在做。class MediaField(FileField):    def __init__(self, *args, **kwargs):        self.content_types = kwargs.pop('content_types')        self.max_upload_size = kwargs.pop('max_upload_size')        super(MediaField, self).__init__(*args, **kwargs)模型中的活动字段：media = MediaField(upload_to='media',  # this will create a folder in MEDIA_ROOT                   content_types=['jpeg', 'jpg', 'png'],                   max_upload_size=5242880)错误： KeyError: 'content_types'stacktrace：    (efs-cP0vQdei) user@right:~/Documents/websites/efs$ ./manage.py makemigrationsTraceback (most recent call last):  File "./manage.py", line 15, in <module>    execute_from_command_line(sys.argv)  File "/home/user/.local/share/virtualenvs/efs-cP0vQdei/lib/python3.6/site-packages/django/core/management/__init__.py", line 371, in execute_from_command_line    utility.execute()  File "/home/user/.local/share/virtualenvs/efs-cP0vQdei/lib/python3.6/site-packages/django/core/management/__init__.py", line 365, in execute    self.fetch_command(subcommand).run_from_argv(self.argv)  File "/home/user/.local/share/virtualenvs/efs-cP0vQdei/lib/python3.6/site-packages/django/core/management/base.py", line 288, in run_from_argv    self.execute(*args, **cmd_options)  File "/home/user/.local/share/virtualenvs/efs-cP0vQdei/lib/python3.6/site-packages/django/core/management/base.py", line 335, in execute    output = self.handle(*args, **options)  File "/home/user/.local/share/virtualenvs/efs-cP0vQdei/lib/python3.6/site-packages/django/core/management/commands/makemigrations.py", line 133, in handle    ProjectState.from_apps(apps),  File "/home/user/.local/share/virtualenvs/efs-cP0vQdei/lib/python3.6/site-packages/django/db/migrations/state.py", line 222, in from_apps    model_state = ModelState.from_model(model)

Answer 1

我想出了解决方案：

在自定义字段类中添加一个解构函数：

def deconstruct(self):

    name, path, args, kwargs = super(MediaField, self).deconstruct()

    kwargs['content_types'] = self.content_types

    kwargs['max_upload_size'] = self.max_upload_size

    return name, path, args, kwargs