What is RAP?
SAP RAP (Restful Application Programming Model) is a modern programming framework provided by SAP for building cloud ready, Fiori optimized, and OData-based applications using ABAP. It is the go-to approach for developing applications in SAP S/4HANA and SAP BTP ABAP Environment.
In essence, it is the standard and advanced technique for developing Fiori apps and web-based APIs directly in the ABAP environment. It provides a structured, efficient, and standardized way to create services that are intrinsically optimized for SAP HANA and deliver the modern SAP Fiori user experience.
Key Aspects
RAP applications follow a structured, layered architecture and rely on several core concepts, tools, and frameworks, including:
- RESTful Principles: RAP applications adhere to Representational State Transfer principles, making them inherently scalable, stateless, and interoperable.
- Core Data Services (CDS): CDS is the foundation for data access and manipulation in RAP. It defines the data model and exposes it as powerful, semantically rich views.
- OData Protocol: RAP exposes business services as OData (Open Data Protocol) services, which are widely consumed by various front-end technologies, especially SAP Fiori.
- Business Objects (BOs): These represent real-world business entities (e.g., Sales Order, Travel) with their data model and transactional behavior.
- ABAP Development Tools (ADT) in Eclipse: ADT is the exclusive Integrated Development Environment (IDE) for RAP development, offering a modern and efficient development experience.
- Data Modeling Layer (CDS Views): This layer defines the application’s data model using ABAP CDS View Entities.
- Behavior Definition Layer: This layer defines the transactional behavior of business objects using Behavior Definitions (BDLs). It specifies standard operations (Create, Update, Delete) and custom actions, validations, and determinations.
- Behavior Implementation Layer: Here, the actual ABAP logic for the behaviors defined in the BDL is implemented using Behavior Implementation Classes. This is where business rules, data manipulations, and integration logic reside.
Why is it useful in an SAP development project?
RAP is crucial and useful for developing SAP solutions due to several key benefits:
- Clean Core Compliance: Enables decoupled extensions, reducing custom code and simplifying upgrades, crucial for S/4HANA Cloud.
- Cloud-Ready by Design: Optimized for cloud platforms including S/4HANA Cloud, On-Premise (2020+), and SAP BTP ABAP.
- Simplified Fiori UI: Minimizes manual coding by using CDS annotations, ideal for SAP Fiori Elements.
- Service-Oriented: Promotes reusable OData services for both UI and API integration.
- Built-in Features: Comes with transaction handling, draft, concurrency control, and authorization — reducing development overhead.
- Flexible Development Models: Supports both Managed (automated) and Unmanaged (manual) approaches, allowing full control when needed.
- Reduced Technical Debt: Encourages clean coding practices and abstraction layers, avoiding costly long-term maintenance.
- Boosted Developer Productivity: Speeds up development with automatic support for filtering, pagination, and more, far more efficient than legacy tools.
