图像文件将在Gallery实例之前保存。因此，您必须通过使用带有状态的Gallery实例本身的信号将保存分为两个阶段：
from django.db.models.signals import post_save, pre_savefrom django.dispatch import receiver_UNSAVED_FILEFIELD = 'unsaved_filefield'@receiver(pre_save, sender=Image)def skip_saving_file(sender, instance, **kwargs): if not instance.pk and not hasattr(instance, _UNSAVED_FILEFIELD): setattr(instance, _UNSAVED_FILEFIELD, instance.image) instance.image = None@receiver(post_save, sender=Image)def save_file(sender, instance, created, **kwargs): if created and hasattr(instance, _UNSAVED_FILEFIELD): instance.image = getattr(instance, _UNSAVED_FILEFIELD) instance.save() # delete it if you feel uncomfortable... # instance.__dict__.pop(_UNSAVED_FILEFIELD)
upload_path_handler看起来像
def upload_path_handler(instance, filename): import os.path fn, ext = os.path.splitext(filename) return "site_media/images/gallery/{id}{ext}".format(id=instance.pk, ext=ext)如果字段仅用于图像上传，我建议使用ImageField而不是FileField进行类型检查。另外，您可能希望规范化文件名扩展名（由于mimetype而不需要），例如
def normalize_ext(image_field): try: from PIL import Image except importError: import Image ext = Image.open(image_field).format if hasattr(image_field, 'seek') and callable(image_field.seek): image_field.seek(0) ext = ext.lower() if ext == 'jpeg': ext = 'jpg' return '.' + ext
