# Developing Sap Rap

> Tactical Blueprint for RESTful ABAP Programming (RAP) and CDS Modeling. Focuses on 'Clean Core' compliant on-stack extensibility in S/4HANA Cloud.

- Skill: `gitwalter/developing-sap-rap` (Agent Skill, multi-file: 21 files)
- Install (CLI): `npx skillmds@latest add gitwalter/developing-sap-rap`
- Raw SKILL.md: https://api.skillmd.com/api/skills/gitwalter/developing-sap-rap/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: DevOps & Infra
- Author: gitwalter (https://skillmd.com/u/gitwalter)
- Updated: 2026-09-10
- Page: https://skillmd.com/skills/gitwalter/developing-sap-rap

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# Capability Manifest: SAP Enterprise RAP

This blueprint provides the **procedural truth** for building production-grade on-stack extensions using the RESTful ABAP Programming Model.

## When to Use

This skill should be used when completing tasks related to sap enterprise rap.

## Process

Follow these procedures to build production-grade on-stack extensions:

### Procedure 1: Data Modeling for Truth (CDS)
1.  **Strict Layering**: Use `I_` (Interface) views for data modeling and `C_` (Consumption) views for UI projection.
2.  **Released Successor Check**: Never use `MARA`, `VBAK`, etc. Search the API Business Hub for released success (e.g., `I_SalesOrder`).
3.  **Semantic Annotations**: Label every field with `@EndUserText.label` and provide unit/currency bindings.

### Procedure 2: Managed Behavior Implementation (BDEF)
1.  **Draft Mandatory**: Always use `with draft` for multi-step transactional logic to ensure data integrity.
2.  **Strict Mode**: Use `strict ( 2 );` to enforce modern ABAP Cloud syntax and locking rules.
3.  **Determinations & Validations**:
    - Use `determination` for side effects (e.g., calculating total price).
    - Use `validation` for business rules with proper message reporting via `%msg`.

### Procedure 3: Service Exposure & Binding
1.  **Granular Exposure**: Only expose view entities required for the specific business task in the `Service Definition`.
2.  **OData v4 Preference**: Always use OData v4 for new Fiori Elements applications unless backward compatibility is required.

## Process (Fail-State & Recovery)

| Symptom | Probable Cause | Recovery Operation |
| :--- | :--- | :--- |
| **Short Dump (Locked)** | Missing ETag or Total ETag mismatch. | Implement `lock master total etag last_changed_at` in the BDEF. |
| **Draft Activation Fail** | Validation error in the draft layer. | Inspect the `reported` and `failed` parameters in the behavior pool; provide clear `%element` mapping for UI highlighting. |
| **Syntax Error (Cloud)** | Use of non-released APIs or legacy syntax. | Replace with `successor` components identified via the ADT "Release State" tab. |

## Prerequisites

| Action | Tool / Command |
| :--- | :--- |
| Create CDS | `ADT -> New Data Definition` |
| Define Behavior | `ADT -> New Behavior Definition` |
| Test OData | `Fiori Elements Preview / Gateway Client` |
| Deploy | `MTA / Transport Management` |

## Best Practices
Before finalizing any RAP object, verify:
- [ ] No direct standard table modifications.
- [ ] Only released SAP APIs used.
- [ ] Mandatory Audit fields (`created_at`, `last_changed_at`) implemented.
- [ ] Draft handling enabled for transactional entities.