在django admin中验证图像大小

Question

我看到很多有Django应用程序的图片上传人员在上传后会自动调整图片大小.对某些情况来说这很好,但我不想这样做.相反,我只是想强制用户上传已经适当大小的文件.

我想要一个ImageField,我强制用户上传100x200的图像.如果他们上传的图片不是那么大,我希望管理表单返回无效.我也希望能够为宽高比做同样的事情.我想强制用户上传16:9的图像并拒绝任何不符合的上传.

我已经知道如何获取图像的宽度和高度,但是在图像上传之后我才能做到服务器端,并且表单已成功提交.如果可能,我如何提前检查？

Answer 1

正确的地方是在表单验证期间.
一个简单的例子(稍后将编辑/集成更多信息):

from django.core.files.images import get_image_dimensions
from django.contrib import admin
from django import forms

class myForm(forms.ModelForm):
   class Meta:
       model = myModel
   def clean_picture(self):
       picture = self.cleaned_data.get("picture")
       if not picture:
           raise forms.ValidationError("No image!")
       else:
           w, h = get_image_dimensions(picture)
           if w != 100:
               raise forms.ValidationError("The image is %i pixel wide. It's supposed to be 100px" % w)
           if h != 200:
               raise forms.ValidationError("The image is %i pixel high. It's supposed to be 200px" % h)
       return picture

class MyAdmin(admin.ModelAdmin):
    form = myForm

admin.site.register(Example, MyAdmin)

Answer 2

在您的模型文件中使用此函数，

from django.core.exceptions import ValidationError

def validate_image(fieldfile_obj):
    filesize = fieldfile_obj.file.size
    megabyte_limit = 2.0
    if filesize > megabyte_limit*1024*1024:
        raise ValidationError("Max file size is %sMB" % str(megabyte_limit))

class Company(models.Model):
    logo = models.ImageField("Logo", upload_to=upload_logo_to,validators=[validate_image], blank=True, null=True,help_text='Maximum file size allowed is 2Mb')