59 lines
2.1 KiB
JavaScript
59 lines
2.1 KiB
JavaScript
////////////////////////////////////////////////////////////////////////////
|
|
//
|
|
// 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.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 SELECT.from (Books, book, b => { b.title, b.price })
|
|
return OrdersService.create ('Orders').entries({
|
|
OrderNo: 'Order at '+ (new Date).toLocaleString(),
|
|
Items: [{ product:{ID:`${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})
|
|
})
|
|
|
|
//
|
|
// 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 { product, deltaAmount } = msg.data
|
|
return UPDATE (Books) .where ('ID =', product)
|
|
.and ('stock >=', deltaAmount)
|
|
.set ('stock -=', deltaAmount)
|
|
})
|
|
}
|