CODEWITHSUNDEEP
pythonflaskwtformsflask-wtforms
Viorel
Viorel

Reputation: 1468

WTForms validation bound to model validation

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
    )
    //...

I have to validate the Invoice.issued_date based on issued_no which is auto generated. issued_date can't be lower than any other Invoice.issued_date where Invoice.issued_no is lower.

e.g:

// 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

How can i do that?

Upvotes: 1

Views: 447

Answers (1)

Miguel Grinberg
Miguel Grinberg

Reputation: 67479

You can add a custom validator to your Form class. For example:

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')

Upvotes: 2

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