rebuild sample to self cont

multitenancy/srv/admin-service.cds

@@ -0,0 +1,7 @@
+using { sap.capire.bookshop as my } from '../db/schema';
+
+//service AdminService @(requires:'admin') {
+service AdminService {
+  entity Books as projection on my.Books;
+  entity Authors as projection on my.Authors;
+}

multitenancy/srv/admin-service.js

@@ -0,0 +1,12 @@
+const cds = require('@sap/cds')
+
+module.exports = cds.service.impl (function(){
+  this.before ('NEW','Authors', genid)
+  this.before ('NEW','Books', genid)
+})
+
+/** Generate primary keys for target entity in request */
+async function genid (req) {
+  const {ID} = await cds.tx(req).run (SELECT.one.from(req.target).columns('max(ID) as ID'))
+  req.data.ID = ID - ID % 100 + 100 + 1
+}

multitenancy/srv/cat-service.cds

@@ -0,0 +1,16 @@
+using { sap.capire.bookshop as my } from '../db/schema';
+service CatalogService @(path:'/browse') {
+
+  /** For displaying lists of Books */
+  @readonly entity ListOfBooks as projection on Books
+  excluding { descr };
+
+  /** For display in details pages */
+  @readonly entity Books as projection on my.Books { *,
+    author.name as author
+  } excluding { createdBy, modifiedBy };
+
+  //@__requires: 'authenticated-user'
+  action submitOrder ( book: Books:ID, amount: Integer ) returns { stock: Integer };
+  event OrderedBook : { book: Books:ID; amount: Integer; buyer: String };
+}

multitenancy/srv/cat-service.js

@@ -0,0 +1,26 @@
+const cds = require('@sap/cds')
+const { Books } = cds.entities ('sap.capire.bookshop')
+
+class CatalogService extends cds.ApplicationService { init(){
+
+  // Reduce stock of ordered books if available stock suffices
+  this.on ('submitOrder', async req => {
+    const {book,amount} = req.data
+    let {stock} = await SELECT `stock` .from (Books,book)
+    if (stock >= amount) {
+      await UPDATE (Books,book) .with (`stock -=`, amount)
+      await this.emit ('OrderedBook', { book, amount, buyer:req.user.id })
+      return { stock }
+    }
+    else return req.error (409,`${amount} exceeds stock for book #${book}`)
+  })
+
+  // Add some discount for overstocked books
+  this.after ('READ','ListOfBooks', each => {
+    if (each.stock > 111) each.title += ` -- 11% discount!`
+  })
+
+  return super.init()
+}}
+
+module.exports = { CatalogService }

multitenancy/srv/multitenancy-service.cds

@@ -1,15 +0,0 @@
-using {sap.capire.bookshop as bookshop } from '../../bookshop/db/schema';
-using {sap.capire.orders as orders } from '../../orders/db/schema';
-
-service MultitenancyService {
-  entity Books as projection on bookshop.Books;
-  entity Orders as projection on orders.Orders;
-  entity Orders_Items as projection on orders.Orders_Items;
-}
-
-using AdminService   from '../../bookshop/srv/admin-service';
-using CatalogService from '../../bookshop/srv/cat-service';
-
-annotate AdminService    with @restrict : false;
-annotate CatalogService  with @restrict : false;
-

multitenancy/srv/orders-service.cds

@@ -0,0 +1,5 @@
+using { sap.capire.orders as my } from '../db/schema';
+
+service OrdersService {
+  entity Orders as projection on my.Orders;
+}

multitenancy/srv/orders-service.js

@@ -0,0 +1,37 @@
+const cds = require ('@sap/cds')
+class OrdersService extends cds.ApplicationService {
+
+  /** register custom handlers */
+  init(){
+    const { Orders_Items:OrderItems } = this.entities
+
+    this.before ('UPDATE', 'Orders', async function(req) {
+      const { ID, Items } = req.data
+      if (Items) for (let { product_ID, amount } of Items) {
+        const { amount:before } = await cds.tx(req).run (
+          SELECT.one.from (OrderItems, oi => oi.amount) .where ({up__ID:ID, product_ID})
+        )
+        if (amount != before) await this.orderChanged (product_ID, amount-before)
+      }
+    })
+
+    this.before ('DELETE', 'Orders', async function(req) {
+      const { ID } = req.data
+      const Items = await cds.tx(req).run (
+        SELECT.from (OrderItems, oi => { oi.product_ID, oi.amount }) .where ({up__ID:ID})
+      )
+      if (Items) await Promise.all (Items.map(it => this.orderChanged (it.product_ID, -it.amount)))
+    })
+
+    return super.init()
+  }
+
+  /** order changed -> broadcast event */
+  orderChanged (product, deltaAmount) {
+    // Emit events to inform subscribers about changes in orders
+    console.log ('> emitting:', 'OrderChanged', { product, deltaAmount })
+    return this.emit ('OrderChanged', { product, deltaAmount })
+  }
+
+}
+module.exports = OrdersService