In many Odoo implementations, user interface behavior is too rigid. Business processes evolve, and the way fields should behave — whether they are visible, required, or read-only — may depend on dynamic conditions: user role, record status, or other domain rules. Hard-coding these conditions into XML views becomes a maintenance burden and rapidly becomes unscalable.
By introducing a dynamic rule engine in Odoo, you can externalize UI logic into configurable rules. These rules define under which conditions a certain field should be hidden, required, or non-editable. This model-level approach empowers businesses with greater agility, maintainability, and control over their Odoo user interface.
The Problem: Static UI Behavior in Odoo
- Limited Flexibility: Odoo’s standard XML-based attrs system makes behavior static. Once deployed, changing conditions requires editing XML, which is error-prone and repetitive.
- Scattered Logic: Conditions are often duplicated in many views. If you want to change behavior, you must update all relevant views manually.
- Maintenance Overhead: As the business grows or rules change, keeping view modifications synchronized becomes cumbersome.
- Role-Specific Needs: Different users or roles often require different UI experiences, but static XML cannot easily adapt to all these scenarios without a complex and fragile setup.
The Solution: Dynamic Rule-Based UI Control
By creating a rule engine at the model level, you define:
- Which fields are targeted
- Under what domain-based conditions (logic expressed as domain)
- What behavior each field should have: read-only, required, invisible
- Who is subject to the rule (via user or role applicability)
When a user loads a view, the system:
- Evaluates relevant rules for the current model and user
- Converts the domain logic into a Python boolean expression
- Parses the XML of the view
- Injects modifiers (readonly, required, invisible) dynamically based on the evaluated expression
- Returns the modified view to the client
This approach separates UI behavior from static XML, making it configurable and maintainable.
Architecture & Components
- Base Model Override: A custom abstract model inherits from Odoo’s base and overrides get_view to handle rule application.
- Rule Storage: A dedicated model holds rule definitions — including the target fields, conditions (domains), and type of behavior.
- Safe Evaluation: Rules’ conditions are safely evaluated using safe_eval, ensuring only domain expressions are parsed.
- Domain-to-Expression Compiler: A helper method transforms Odoo-style domain lists into valid Python expressions.
- XML Manipulation: Using the lxml library, the system parses the view’s XML, locates field nodes, and applies the necessary modifier attributes based on the evaluated conditions.
- Modifiers Injection: For matching fields, it modifies both the XML tree and the JSON modifiers attribute to apply the correct UI behavior dynamically.
Security and Performance Considerations
- Safe Usage of safe_eval: Only evaluate trusted domain expressions. Avoid arbitrary code execution by limiting rule authors to trusted administrators.
- Evaluation Overhead: Rule evaluation and XML parsing add runtime cost. Be mindful of performance, especially for complex rules or large forms.
- Testing: Thoroughly test rules under different user scenarios and view types to ensure correctness and avoid unexpected UI issues.
- Logging & Monitoring: Log rule evaluation outcomes and applied modifiers, so you can debug and trace dynamic behavior when something doesn’t work as expected.
Conclusion
Building a dynamic rule engine for Odoo views enables a smarter, more adaptable, and maintainable user interface. By moving field behavior logic from static XML into Python-managed rules, businesses gain the power to adapt UI behavior in real time — all based on role, context, or record state.
This approach vastly reduces duplication, lowers the barrier for managing view logic, and improves the overall user experience. Odoo administrators and developers alike benefit from cleaner architecture, stronger control, and more agility.