django - 如何使用 Django 信号(Pre_save,Post_save)从“B”模型的 ImageField 设置“A”模型的 ImageField
问题描述
这是我的模型
from django.db import models
from django.utils import timezone
# Create your models here.
class send_message_model(models.Model):
mail = models.EmailField(max_length=100)
msg = models.TextField(max_length=500)
class projectmodel(models.Model):
project_name = models.CharField(max_length=100)
project_url = models.URLField()
project_desc = models.CharField(max_length=200)
project_short_desc = models.CharField(max_length=100,default='')
project_date = models.DateField(default=timezone.now)
rate = models.IntegerField()
project_thumb = models.ImageField(blank=True)
def __str__(self):
return f'{self.id}'
class projectimage(models.Model):
project_id = models.ForeignKey(projectmodel,on_delete=models.CASCADE,blank=True,null=True)
project_pic = models.FileField(upload_to = 'imgs/')
time = models.DateTimeField( auto_now=False, auto_now_add=True)
def __str__(self):
return f"{self.project_id}"
我想将ProjectImage's
图像设置为我的projectmodel
imageField,同时保存projectmodel
我试过这个,
from django.contrib.auth.models import User
from Portfolio.models import projectimage,projectmodel
from django.db.models.signals import post_save,pre_save
from django.dispatch import receiver
def do_something(sender,instance,**kwargs):
print("User Saved")
print(sender)
print(instance)
# print(created)
pre_save.connect(do_something,sender = User)
@receiver(pre_save,sender=projectmodel)
def add_image(sender,instance,**kwargs):
if not instance.project_thumb:
print("Image Empty")
instance_id = instance.id
img = projectimage.objects.filter(id = instance_id).order_by('id')[0]
print(img)
print(type(img))
thumb = projectmodel.objects.filter(id = instance_id)
thumb_save = thumb(project_thumb = img)
thumb_save.save()
else:
print("Image here")
但它不起作用,显示此错误,
TypeError at /admin/Portfolio/projectmodel/4/change/
'QuerySet' object is not callable
Request Method: POST
Request URL: http://127.0.0.1:8000/admin/Portfolio/projectmodel/4/change/
Django Version: 3.1.4
Exception Type: TypeError
Exception Value:
'QuerySet' object is not callable
Exception Location: C:\Django Python\SecondPortfolio\Portfolio\signals.py, line 27, in add_image
Python Executable: C:\Program Files\Python38\python.exe
Python Version: 3.8.2
Python Path:
['C:\\Django Python\\SecondPortfolio',
'C:\\Program Files\\Python38\\python38.zip',
'C:\\Program Files\\Python38\\DLLs',
'C:\\Program Files\\Python38\\lib',
'C:\\Program Files\\Python38',
'C:\\Users\\Rak1b\\AppData\\Roaming\\Python\\Python38\\site-packages',
'C:\\Program Files\\Python38\\lib\\site-packages']
Server time: Tue, 19 Jan 2021 20:39:51 +0000
解决后出现新问题
AttributeError at /admin/Portfolio/projectmodel/1/change/
'projectimage' object has no attribute '_committed'
Request Method: POST
Request URL: http://127.0.0.1:8000/admin/Portfolio/projectmodel/1/change/
Django Version: 3.1.4
Exception Type: AttributeError
Exception Value:
'projectimage' object has no attribute '_committed'
Exception Location: C:\Users\Rak1b\AppData\Roaming\Python\Python38\site-packages\django\db\models\fields\files.py, line 305, in pre_save
Python Executable: C:\Program Files\Python38\python.exe
Python Version: 3.8.2
Python Path:
['C:\\Django Python\\SecondPortfolio',
'C:\\Program Files\\Python38\\python38.zip',
'C:\\Program Files\\Python38\\DLLs',
'C:\\Program Files\\Python38\\lib',
'C:\\Program Files\\Python38',
'C:\\Users\\Rak1b\\AppData\\Roaming\\Python\\Python38\\site-packages',
'C:\\Program Files\\Python38\\lib\\site-packages']
Server time: Tue, 19 Jan 2021 22:31:15 +0000
这将非常有帮助,如果有人给我想法,如何在另一个模型上设置图像
解决方案
filter()返回 aQuerySet
并使用img.project_pic代替img
最佳使用get()
。
from django.core.files.base import ContentFile
...
def add_image(sender,instance,**kwargs):
...
thumb = projectmodel.objects.get(id=instance_id)
thumb.project_thumb.save(img.project_pic.name, ContentFile(img.project_pic.read()), save=False)
thumb.save()
或者
...
def add_image(sender,instance,**kwargs):
...
thumb = projectmodel.objects.get(id=instance_id)
thumb.project_thumb = img.project_pic
thumb.save()
如果你想用filter()
比也得用update()
thumb.update(...)
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