Side-by-Side Extensions

// CAP Service — Side-by-side extension consuming S/4HANA Sales Orders
// srv/sales-enhancement.cds

using {API_SALES_ORDER_SRV as external} from '../srv/external/API_SALES_ORDER_SRV';

service SalesEnhancementService @(path: '/sales-ext') {

  // Projection over S/4HANA Sales Order — read via OData V4
  @readonly
  entity SalesOrders as projection on external.A_SalesOrder {
    SalesOrder,
    SoldToParty,
    TotalNetAmount,
    TransactionCurrency,
    SalesOrderDate,
    // Extension custom fields (stored in HANA Cloud HDI)
    virtual approvalStatus : String,
    virtual assignedAgent   : String,
    virtual dueDate         : Date,
  }

  // Custom extension entity — purely in HANA Cloud (no S/4 involvement)
  entity SalesApprovals : managed {
    key ID           : UUID;
        salesOrder   : String(10);
        requestedBy  : String(100);
        approvedBy   : String(100);
        status       : String enum { pending; approved; rejected; } default 'pending';
        comments     : LargeString;
  }

  // Action: update approval status + notify S/4HANA via API
  action submitApproval(salesOrder: String, decision: String, comment: String) returns Boolean;
}

// srv/sales-enhancement.ts — Action handler
import cds from '@sap/cds'

export class SalesEnhancementService extends cds.ApplicationService {
  async init() {
    const s4 = await cds.connect.to('API_SALES_ORDER_SRV')

    this.on('submitApproval', async (req) => {
      const { salesOrder, decision, comment } = req.data

      // 1. Update local approval record in HANA Cloud
      await UPDATE('SalesApprovals')
        .set({ status: decision, comments: comment, approvedBy: req.user.id })
        .where({ salesOrder })

      // 2. If approved — update S/4HANA via released API
      if (decision === 'approved') {
        await s4.run(
          UPDATE('A_SalesOrder')
            .set({ YY1_ApprovalStatus_SDH: 'APPROVED' })
            .where({ SalesOrder: salesOrder })
        )
      }
      return true
    })

    await super.init()
  }
}