我有两种型号Invoce和Payin。发票可以多付款支付。使用post_save信号更新发票详细信息时。执行创建逻辑后，我将一个Invoice Id附加到Payin实例并保存。这个保存再次触发信号（因为它应该是）这次更新逻辑，即在if的其他部分创建：在那里执行一次payin被添加两次到发票中的付款金额。当我在信号逻辑中保存实例时，如何避免更新逻辑。
class Invoice(BaseEntity):
""" Invoices are generated based on events state"""
STATUS_CHOICES=(
('CREATED', 'Created'),
('CONFIRMED', 'Confirmed'),
('PARTIAL_PAYMENT', 'Partially Paid'),
('RECEIVED', 'Received'),
('CLOSED', 'Closed')
)
customer = models.ForeignKey(
Customer,
related_name='invoices',
)
event = models.ForeignKey(
'booking.Event',
related_name='invoice',
)
generated_date = models.DateField(
verbose_name='date invoice generated'
)
due_date = models.DateField(
verbose_name='date payment is expected'
)
status = models.CharField(
max_length =15,
choices = STATUS_CHOICES,
default = 'CREATED',
)
amount = models.IntegerField(
default=500,
validators=[
MinValueValidator(
10,
message = 'Amount should be greater than 10'
),
MaxValueValidator(
10000000,
message = 'Amount should be less than 10000000'
),
]
)
paid = models.IntegerField(
default=500,
validators=[
MinValueValidator(
10,
message = 'Amount should be greater than 10'
),
MaxValueValidator(
10000000,
message = 'Amount should be less than 10000000'
),
]
)
def get_absolute_url(self):
return reverse('accounting:Invoice_Detail', kwargs={'pk': self.id})
def get_update_url(self):
return reverse('accounting:Invoice_Update', kwargs={'pk': self.id})
def get_delete_url(self):
return reverse('accounting:Invoice_Delete', kwargs={'pk': self.id})
class Payin(BaseEntity):
""" Payins from all customers"""
MODE_CHOICES=(
('BANK', 'Bank'),
('CHEQUE', 'Cheque'),
('DD', 'Demand Draft'),
('CASH', 'Cash'),
)
customer = models.ForeignKey(
'customers.Customer',
related_name='customer_payins',
blank = True,
null = True,
)
event = models.ForeignKey(
'booking.Event',
related_name='event_payins',
blank = True,
null =True,
)
date = models.DateField(
verbose_name='payment date'
)
time = models.TimeField(
verbose_name='payment time'
)
amount = models.IntegerField(
default=500,
validators=[
MinValueValidator(
10,
message = 'Amount should be greater than 10'
),
MaxValueValidator(
10000000,
message = 'Amount should be less than 10000000'
),
]
)
mode = models.CharField(
max_length =15,
choices = MODE_CHOICES,
default = 'CASH',
)
invoice = models.ForeignKey(
Invoice,
related_name='payins',
blank = True,
null = True,
)
def get_absolute_url(self):
return reverse('accounting:Payin_Detail', kwargs={'id': self.id})
def get_update_url(self):
return reverse('accounting:Payin_Update', kwargs={'id': self.id})
def get_delete_url(self):
return reverse('accounting:Payin_Delete', kwargs={'id': self.id})
@receiver(post_save, sender = Payin)
def update_event_invoice_based_on_payin(sender,instance, created, **kwargs):
payin = instance
#print(dir(instance))
if created:
try:
event = Event.objects.get(pk = payin.event.id )
if event.status != 'COMPLETED':
print('advance before save in post_save in create is: ', event.advance)
event.advance = event.advance + payin.amount
event.save()
print('advance after save in post_save in create is: ' , event.advance)
else:
invoice = Invoice.objects.get(event = event.id)
if invoice.paid + payin.amount <= invoice.amount:
print('post_save before save :',invoice.paid )
invoice.paid = (invoice.paid + payin.amount)
print(invoice.paid)
if invoice.paid == invoice.amount:
invoice.status = 'PAID'
invoice.save()
print('post_save after save in paid :',invoice.paid)
payin.invoice = invoice
print('paid')
payin.save()
else:
invoice.status = 'PARTIAL_PAYMENT'
invoice.save()
print('post_save after save in partial payment :',invoice.paid)
payin.invoice = invoice
print('partial payment')
payin.save()
finally:
#del instance._del
pass
else:
event = Event.objects.get(pk = payin.event.id )
if event.status != 'COMPLETED':
print('advance before save in post_save in modify is: ' ,event.advance)
event.advance = event.advance + payin.amount
event.save()
print('advance after save in post_save in modify is: ' , event.advance)
else:
invoice = Invoice.objects.get(event = event.id)
if invoice.paid + payin.amount <= invoice.amount:
#print(invoice.paid + payin.amount)
print('post_save before save in update :',invoice.paid)
invoice.paid = (invoice.paid + payin.amount)
print(invoice.paid)
if invoice.paid == invoice.amount:
invoice.status = 'PAID'
invoice.save()
print('post_save after save in paid in update :',invoice.paid)
print('paid')
else:
invoice.status = 'PARTIAL_PAYMENT'
invoice.save()
print('post_save after save in partial payment in update :',invoice.paid)
print('partial payment')