composites

fiori/srv/admin-service.cds

@@ -1,3 +0,0 @@
-// Proxy for importing services from bookshop sample
-using from '@capire/bookshop';
-annotate AdminService with @impl:'srv/admin-service.js';

fiori/srv/admin-service.js

@@ -1,8 +0,0 @@
-const cds = require('@sap/cds')
-
-module.exports = cds.service.impl (async function() {
-  const {Books} = cds.entities
-  const {ID} = await SELECT.one.from(Books).columns('max(ID) as ID')
-  let newID = ID - ID % 100 + 100
-  this.before ('NEW','Books', req => req.data.ID = ++newID)
-})

fiori/srv/mashup.cds

@@ -0,0 +1,25 @@
+////////////////////////////////////////////////////////////////////////////
+//
+//    Mashing up imported models...
+//
+
+using { sap.capire.bookshop.Books } from '@capire/bookshop';
+
+//
+//  Extend Books with access to Reviews and average ratings
+//
+
+using { ReviewsService.Reviews } from '@capire/reviews';
+extend Books with {
+  reviews : Composition of many Reviews on reviews.subject = $self.ID;
+  rating  : Decimal;
+}
+
+//
+//  Extend Orders with Books as articles
+//
+
+using { sap.capire.orders.OrderItems } from '@capire/orders';
+extend OrderItems with {
+  book : Association to Books on article = book.ID
+}

fiori/srv/mashup.js

@@ -0,0 +1,59 @@
+////////////////////////////////////////////////////////////////////////////
+//
+//    Mashing up provided and required services...
+//
+module.exports = async()=>{ // called by server.js
+
+  const cds = require('@sap/cds')
+  const CatalogService = await cds.connect.to ('CatalogService')
+  const ReviewsService = await cds.connect.to ('ReviewsService')
+  const OrdersService = await cds.connect.to ('OrdersService')
+  const db = await cds.connect.to ('db')
+
+  // reflect entity definitions used below...
+  const { Books } = db.entities ('sap.capire.bookshop')
+
+  //
+  // Delegate requests to read reviews to the ReviewsService
+  // Note: prepend is neccessary to intercept generic default handler
+  //
+  CatalogService.prepend (srv => srv.on ('READ', 'Books/reviews', (req) => {
+    console.debug ('> delegating request to ReviewsService')
+    const [id] = req.params, { columns, limit } = req.query.SELECT
+    return ReviewsService.tx(req).read ('Reviews',columns).limit(limit).where({subject:String(id)})
+  }))
+
+  //
+  // Create an order with the OrdersService when CatalogService signals a new order
+  //
+  CatalogService.on ('OrderedBook', async (msg) => {
+    const { book, amount, buyer } = msg.data
+    const { title, price } = await db.tx(msg).read (Books, book, b => { b.title, b.price })
+    return OrdersService.tx(msg).create ('Orders').entries({
+      OrderNo: 'Order at '+ (new Date).toLocaleString(),
+      Items: [{ article:`${book}`, title, price, amount }],
+      buyer, createdBy: buyer
+    })
+  })
+
+  //
+  // Update Books' average ratings when ReviewsService signals updatd reviews
+  //
+  ReviewsService.on ('reviewed', (msg) => {
+    console.debug ('> received:', msg.event, msg.data)
+    const { subject, rating } = msg.data
+    return UPDATE(Books,subject).with({rating})
+    // ^ Note: the framework will execute this and take care for db.tx
+  })
+
+  //
+  // Reduce stock of ordered books for orders are created from Orders admin UI
+  //
+  OrdersService.on ('OrderChanged', async (msg) => {
+    console.debug ('> received:', msg.event, msg.data)
+    const { article, deltaAmount } = msg.data
+    return UPDATE (Books) .where ('ID =', article)
+    .and ('stock >=', deltaAmount)
+    .set ('stock -=', deltaAmount)
+  })
+}