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