Django Signals - 如何保存实例

Question

我正在使用 Django Rest Framework 上传视频。现在我想为我的视频文件添加缩略图。每当保存视频对象时，我都想创建一个缩略图并设置其 thumbnail 字段。

我的视频模型如下所示：

class Video(models.Model):
    created = models.DateTimeField(auto_now_add=True)
    text = models.CharField(max_length=100, blank=True)
    video = models.FileField(upload_to='Videos/',blank=True)
    thumbnail = models.ImageField(upload_to = 'Images/', blank = True)

我的信号处理程序如下所示：

from moviepy.video.io.VideoFileClip import VideoFileClip
from posts.models import Video
from django.db.models.signals import post_save
from django.dispatch import receiver
from settingsFolderOfProject.settings import MEDIA_ROOT
import os

# when save() of Video is done, create_thumbnail_from_video() is called
@receiver(post_save, sender=Video)
def create_thumbnail_from_video(sender, instance, created, **kwargs):
    if created:
        # create the clip using moviepy's VideoFileClip class
        clip = VideoFileClip(os.path.join(MEDIA_ROOT, instance.video.name))
        # create the frame at 1st second and set it to instance's thumbnail field
        instance.thumbnail = clip.save_frame(os.path.join(MEDIA_ROOT, 'Images/thumbnail.jpg'),t='00:00:01') 
        # save the instance 
        instance.save()       # <--- I think this op does not work properly

我必须改变什么？缩略图文件按预期在文件夹中创建，但 Django 没有设置我的 Video 模型实例的 thumbnail 字段。创建的 Video 实例的 thumbnail 字段仍设置为空。

Answer 1

clip.save_frame() 没有 return 任何东西。相反做

path = os.path.join(MEDIA_ROOT, 'Images/thumbnail.jpg')
clip.save_frame(path,t='00:00:01') 
instance.thumbnail = path
instance.save()

注：尚未测试。如果问题仍然存在，请发表评论。谢谢...

Django Signals - 如何保存实例

Django Signals - How to save the instance

django

thumbnails

django-signals

django-rest-framework

moviepy