ValueError: Cannot assign "(<User: testuser>,)": "Message.user" must be a "User" instance

Question

尝试创建一个具有多个聊天室的简单实时聊天应用程序。尝试在消息模型中添加新消息时，出现 ValueError。

model.py:

class Message(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    room = models.ForeignKey(Room, on_delete=models.CASCADE)
    body = models.TextField()
    updated = models.DateTimeField(auto_now=True)
    created = models.DateTimeField(auto_now_add=True)

view.py:

def addMessage(request):
    user = User.objects.get(username = request.POST['username']),
    room = Room.objects.get(id = request.POST['room_id']),
    message = request.POST['message'],
    Message.objects.create(
        user = user,
        room = room,
        body = message
    )
    return HttpResponse("Message Sent Sucessfully!")

我见过很多类似的问题，但是 none 的解决方案有效。

谢谢。

Answer 1

由于您在以下行中添加了尾随逗号

user = User.objects.get(username = request.POST['username']),
room = Room.objects.get(id = request.POST['room_id']),
message = request.POST['message'],

这些变量变成 python tuple 并导致错误，因为值的类型错误。

删除尾随的逗号应该可以解决问题。

user = User.objects.get(username = request.POST['username'])
room = Room.objects.get(id = request.POST['room_id'])
message = request.POST['message']

ValueError: Cannot assign "(<User: testuser>,)": "Message.user" must be a "User" instance

ValueError: Cannot assign "(<User: testuser>,)": "Message.user" must be a "User" instance

python-3.x

django

django-models

serialization

django-rest-framework