防止 Django imageField 上传/保存图像

Question

我有一个带有图像字段的模型，我在保存图像之前执行了各种自定义逻辑。例如，我调整图像大小并将其上传到服务器。然后我将它的路径链接到文件名。

所以我不需要 Django 来保存图像，它会覆盖我自定义大小的图像。

我想做的是防止 django imagefield 自动将图像上传到服务器。可以这样做吗？

更新代码：

型号：

class Document(models.Model):
    myField = models.CharField(max_length=500)
    image_main = models.ImageField(blank=True, upload_to=change_filename_to_slug)
    image_thumbsize_big = models.ImageField(blank=True)
    image_thumbsize_small = models.ImageField(blank=True)

查看：

def list(request):
    # Handle file upload
    if request.method == 'POST':
        form = DocumentForm(request.POST, request.FILES)
        if form.is_valid():
            instance        = form.save(commit=False)  # Creates a modifiable instance

            instance.save()
            return HttpResponseRedirect('/list/')
    else: .....

处理文件上传过程的函数。它处理我需要的所有过程，创建适当大小的文件并将其放入目录中。问题是当实例由 django 保存时，它会自己创建文件，因此我有 2 个文件并且使用了错误的文件。 我只想短路 django 并阻止 imagefield 表单创建它的文件：

def change_filename_to_slug(instance, filename):

    file = instance.image_main
    # Variables
    save_media_dir = instance.mediaUrl + instance.saveImagepath  # Passed by model
    base_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__))) + save_media_dir
    im = Image.open(file)
    slug = slugify(instance.myField, allow_unicode=True)
    finalpath = None
    has_iterated = 0

for key, value in sizes.items():
    im_reset = im
    im_reset = im_reset.resize(value, Image.ANTIALIAS)
    save_dir = base_dir + slug + key
    field_file_name = save_media_dir


    if im.format.lower() == 'png':
        # Save in folder : no need to save again
        im_reset.save(save_dir + '.png', compress_level=png_compress, format='PNG')  
        # Save names in fields:
        if has_iterated == 0: finalpath =  'dir/' +  slug + key + '.png'  
        if has_iterated == 1: instance.image_thumbsize_big = field_file_name + slug + key + '.png'
        if has_iterated == 2: instance.image_thumbsize_small = field_file_name + slug + key + '.png'
        has_iterated += 1


return finalpath

形式：

from .models import Document
from django.forms import ModelForm

class DocumentForm(ModelForm):
    class Meta:
        model = Document
        fields = ['myField', 'image_main', 'image_thumbsize_big', 'image_thumbsize_small']

Answer 1

我会尝试覆盖表单的save 方法：

class DocumentForm(ModelForm):

    def __init__(self, post_data, files_data):
        self.image_main_file = files_data.get('image_main', None)
        return super(DocumentForm, self).__init__(post_data, files_data)

    def save(self, force_insert=False, force_update=False, commit=True):
        instance = super(DocumentForm, self).save(commit=False)
        # do your image magic here, e.g.
        # instance.image_thumbsize_big = field_file_name + slug + key + '.png'

        # you can access your main file with: self.image_main_file
        if commit:
            instance.save()
        return instance

然后在您的列表视图中：

def list(request):
    # Handle file upload
    if request.method == 'POST':
        form = DocumentForm(request.POST, request.FILES)
        if form.is_valid():
            instance        = form.save(commit=True)
            return HttpResponseRedirect('/list/')
    else: .....