This commit is contained in:
D065023
2019-11-29 12:11:29 +01:00
parent c2d0fba1d8
commit 8f3d112558

View File

@@ -2,25 +2,42 @@ const cds = require('@sap/cds')
const { Books } = cds.entities
/** Service implementation for CatalogService */
module.exports = cds.service.impl(function() {
this.after ('READ', 'Books', each => each.stock > 111 && _addDiscount2(each,11))
this.before ('CREATE', 'Orders', _reduceStock)
module.exports = cds.service.impl(function () {
this.after(
'READ',
'Books',
each => each.stock > 111 && _addDiscount2(each, 11)
)
this.before('CREATE', 'Orders', _reduceStock)
})
/** Add some discount for overstocked books */
function _addDiscount2 (each,discount) {
function _addDiscount2 (each, discount) {
each.title += ` -- ${discount}% discount!`
}
/** Reduce stock of ordered books if available stock suffices */
async function _reduceStock (req) {
const { Items: OrderItems } = req.data
return cds.transaction(req) .run (()=> OrderItems.map (order =>
UPDATE (Books) .set ('stock -=', order.amount)
.where ('ID =', order.book_ID) .and ('stock >=', order.amount)
)) .then (all => all.forEach ((affectedRows,i) => {
if (affectedRows === 0) req.error (409,
`${OrderItems[i].amount} exceeds stock for book #${OrderItems[i].book_ID}`
return cds
.transaction(req)
.run(() =>
OrderItems.map(order =>
UPDATE(Books)
.set('stock -=', order.amount)
.where('ID =', order.book_ID)
.and('stock >=', order.amount)
)
)
.then(all =>
all.forEach((affectedRows, i) => {
if (affectedRows === 0)
req.error(
409,
`${OrderItems[i].amount} exceeds stock for book #${
OrderItems[i].book_ID
}`
)
})
)
}))
}