Frappe Syntax: Document Controllers

Document Controllers are Python classes that define all server-side logic for a DocType. EVERY DocType has exactly one controller file. The controller class extends frappe.model.document.Document.

Quick Reference

import frappe
from frappe import _
from frappe.model.document import Document

class SalesOrder(Document):
    def autoname(self):
        """Custom naming logic. Sets self.name."""
        self.name = f"SO-{self.customer_code}-{frappe.utils.now_datetime().year}"

    def validate(self):
        """MAIN validation — runs on EVERY save (insert and update).