mongodb GridFS django FileFiled 默認 widget 只有一個文件上傳框顯示不了字段內容，重寫widget

首先，定位到：FileFiled 默認 widget 源碼：mongoadmin包options.py中，以下：

 1 # Defaults for formfield_overrides. ModelAdmin subclasses can change this
 2 # by adding to ModelAdmin.formfield_overrides.
 3 FORMFIELD_FOR_DBFIELD_DEFAULTS = {
 4     DateTimeField: {
 5         'form_class': forms.SplitDateTimeField,
 6         'widget'    : widgets.AdminSplitDateTime
 7         },
 8     URLField     : {'widget': widgets.AdminURLFieldWidget},
 9     IntField     : {'widget': widgets.AdminIntegerFieldWidget},
10     ImageField   : {'widget': widgets.AdminFileWidget},
11     FileField    : {'widget': widgets.AdminFileWidget},
12     }
13 
14 _fieldgenerator = load_field_generator()()

源碼摘取

而後，根據註釋部分：

# Defaults for formfield_overrides. ModelAdmin subclasses can change this
# by adding to ModelAdmin.formfield_overrides.

重寫widget以下：

 1 from django.contrib.admin.widgets import AdminFileWidget
 2 class FileWidget(AdminFileWidget):
 3     """
 4     A FileField Widget that shows its current value if it has one.
 5     """
 6 
 7     def __init__(self, attrs={}):
 8         super(FileWidget, self).__init__(attrs)
 9 
10     def render(self, name, value, attrs=None):
11         output = []
12         output.append(super(FileWidget, self).render(name, value, attrs))
13         output.append('<p class="help"><textarea name="%s" id="id_%s" rows="10" cols="40" class="vLargeTextField"> %s </textarea></p>' % (name, name, value.read()))
14         return mark_safe(u''.join(output))

MyFileWidget

引入widget以下：

 1 from mongoengine import Document
 2 class AbstractDocument(Document):
 3 
 4     ModelAdmin.formfield_overrides = {
 5         FileField: {'widget': FileWidget},
 6     }
 7 
 8     meta = {
 9         'abstract': True,
10     }

MyDocument