frappe-syntax-controllers

What problem does it solve?

Writing consistent, secure, and maintainable Frappe Document Controllers can be error-prone due to ad-hoc patterns and scattered best practices. This skill consolidates recommended lifecycle hooks, override and extension strategies, doc_events wiring, naming conventions, and flag/permission patterns into a coherent approach.

Core Features & Use Cases

• Lifecycle hooks guidance: before_validate, validate, before_save, on_update, on_change, before_submit, on_submit, before_cancel, on_cancel, and update-after-submit.
• Controller extension mechanisms: override_doctype_class, extend_doctype_class (v16+), and doc_events for granular hooks.
• Paired submit/cancel patterns, naming/autoname strategies (including UUID v16), and use of doc.flags and frappe.flags for runtime coordination.
• DocEvents and extension patterns enabling safe multi-app customization and predictable behavior.
• Use cases: building a new DocType controller, integrating with external systems via whitelists or enqueue, and implementing robust validations.

Quick Start

Create a simple Document Controller by extending Document, implement a basic validate() using super(), and attach a single doc_event in hooks.py to observe the lifecycle.