python - WTForms 验证绑定(bind)到模型验证

Question

models.py

class Invoice(Base, Timestampable):
    __tablename__ = 'invoices'

    issued_no = db.Column(
        db.String(16),
        nullable=False,
        unique=True,
        default=lambda: Invoice.next_issued_no()
    )
    issued_date = db.Column(db.DateTime, nullable=False)
    exchange_rate = db.Column(db.Numeric(10, 2), nullable=False, default=1)
    currency = db.Column(db.String(8), nullable=False, default='RON')
    contract_id = db.Column(db.Integer, db.ForeignKey('contracts.id'))
    contract = db.relationship('Contract')
    customer_id = db.Column(db.Integer, db.ForeignKey('customers.id'))
    customer = db.relationship('Customer')
    due_date = db.Column(db.DateTime, nullable=False)
    description = db.Column(db.String(255), nullable=True)
    rows = db.relationship('InvoiceRow')

    @classmethod
    def next_issued_no(cls):
        invoice = cls.query.with_entities(cls.issued_no) \
            .order_by(desc(cls.issued_no)).first()
        if not invoice:
            return '100000'
        return int(invoice.issued_no) + 1

forms.py

class InvoiceForm(Form):
    issued_date = DateField(
        'Issued Date',
        [validators.Required('Required field')],
        format='%d/%m/%Y'
    )
    exchange_rate = DecimalField(
        'Exchange Rate',
        [validators.Required('Required field')]
    )
    currency = SelectField(
        'Currency',
        [validators.Required('Required field')],
        choices=[
            ('EUR', 'EUR'),
            ('USD', 'USD')
        ]
    )
    contract = QuerySelectField(
        'Contract',
        query_factory=lambda: InvoiceForm.get_contracts()
    )
    customer = QuerySelectField(
        'Customer',
        query_factory=lambda: InvoiceForm.get_customers()
    )
    due_date = DateField(
        'Due',
        [validators.Required('Required field')],
        format='%d/%m/%Y'
    )
    description = TextAreaField(
        'Description',
        [validators.Optional()],
        filters=[strip_filter]
    )
    rows = FieldList(
        FormField(InvoiceRowForm),
        label='Rows',
        min_entries=1
    )
    //...

我必须根据自动生成的issued_no 验证Invoice.issued_date。 Issued_date 不能低于 Invoice.issued_no 较低的任何其他 Invoice.issued_date。

例如:

// valid
100001 01/04/2013
100002 01/05/2013
100003 01/06/2013

// invalid
100001 01/05/2013
100002 01/04/2013
100003 01/06/2013

我怎样才能做到这一点？

Answer 1

您可以将自定义验证器添加到您的 Form 类中。例如:

class InvoiceForm(Form):
    # ...

    def validate_issued_date(self, field):
        last_invoice = Invoice.query.order_by(Invoice.issued_no.desc()).first()
        if field.data < last_invoice.issued_date:
            raise ValidationError('Invoice out of sequence')