创建&从函数内返回默认的ImageFieldFile [英] Create & return a default ImageFieldFile from inside a function

问题描述

在我的UserProfile模型中，我希望有一个函数返回用户的 ImageFileField 对象或默认图像，如果用户没有上传自己的。

In my UserProfile model I would like to have a function which returns either the user's ImageFileField object or a default image if the user has not uploaded their own.

例如：

class UserProfile(models.Model):
    pic = models.ImageField('Headshot',blank=True,
                             upload_to=get_path_and_filename)

    def get_pic(self):
        if self.pic:
            return self.pic
        else:
            # return ImageFileField with a default value

我想要返回一个等价的 ImageFileField ，因为我有过滤器可以使用此对象类型（因此我不能简单地传递一个字符串）...我试着查看源代码但是我不太清楚自己如何去做。

I want to return an equivalent ImageFileField because I have filters that work with this object type (so I can't just pass it a string, easily) ... I tried looking at the source code but I can't quite figure out how to do it myself.

有没有一个简单的方法来初始化一个新的 ImageFileField

Is there an easy way to initialize a new ImageFileField object by passing it a path to an image file and then return it?

PS：我曾经想过使用ImageField的默认设置，但是，似乎较不灵活，因为该文件存储在模型创建...如果我以后想要更改默认文件，我将不得不更新所有具有旧文件的数据库条目。

PS: I had thought about using a default setting for the ImageField, however, it seems less flexible because the file is stored at model creation ... and if I later want to change the default file, I would have to update all the database entries that had the old file.

推荐答案

这可能是一个打字错误，但是您实际想要返回的是 ImageFieldFile 。

It was probably a typo, but what you actually want to return is an ImageFieldFile.

ImageField 使模型的属性实例aa ImageFileDescriptor 。当您访问该属性时，它返回一个 ImageFieldFile 实例。

The ImageField makes the property of the model instance actually aa ImageFileDescriptor. When you access the property, it returns an ImageFieldFile instance.

只要不调用 save（）或 delete（） ImageFieldFile的方法，你可以很容易地组织一个：

As long as you don't call the save() or delete() methods of the ImageFieldFile, you can instanciate one reasonably easily:

from django.db.models.fields.files import ImageFieldFile, FileField

class UserProfile(models.Model):
    # ...

    def get_pic(self):
        if self.pic:
            return self.pic
        return ImageFieldFile(instance=None, field=FileField(),
                              name='pictures/default.jpg')

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