99861ca588
* Bump to cds 4 * Cosmetics in handler code * await and cds.run([...]) instead of Promise.all Co-authored-by: Christian Georgi <[email protected]>
34 lines
999 B
JavaScript
34 lines
999 B
JavaScript
const cds = require('@sap/cds')
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const { Books } = cds.entities
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/** Service implementation for CatalogService */
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module.exports = cds.service.impl(function() {
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this.after ('READ', 'Books', each => each.stock > 111 && _addDiscount2(each,11))
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this.before ('CREATE', 'Orders', _reduceStock)
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})
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/** Add some discount for overstocked books */
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function _addDiscount2 (each,discount) {
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each.title += ` -- ${discount}% discount!`
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}
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/** Reduce stock of ordered books if available stock suffices */
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async function _reduceStock (req) {
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const { Items: orderItems } = req.data
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if (!Array.isArray(orderItems)) return
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const all = await cds.transaction(req).run(orderItems.map(item =>
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UPDATE(Books)
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.set('stock -=', item.amount)
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.where('ID =', item.book_ID).and('stock >=', item.amount)
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))
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all.forEach((affectedRows, i) => {
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if (affectedRows === 0) {
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req.error(409, `${orderItems[i].amount} exceeds stock for book #${orderItems[i].book_ID}`)
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}
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})
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return all
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}
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