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_packages/bookstore/srv/services.js

@@ -0,0 +1,38 @@
+const cds = require('@sap/cds')
+module.exports['sap.capire.bookstore.CatalogService'] = cds.service.impl (async (srv) => {
+
+    const ReviewsService = await cds.connect.to ('sap.capire.reviews.ReviewsService')
+    const { Reviews } = ReviewsService.entities
+    const { Books } = srv.entities
+
+    // delegate requests to reviews service
+    srv.on('READ', 'Reviews', async (req) => {
+        const { SELECT } = cds.ql(req)
+        const results = await SELECT.from (Reviews)
+
+        // TODO: Should actually be using .where of fluent query API
+        if (req.query.SELECT.where) {
+            return results.filter (row => row.subject === req.query.SELECT.where[2].val)
+        }
+
+        return results
+    })
+
+    // react on event messages from reviews service
+    ReviewsService.on ('reviewed', (msg) => {
+        console.debug ('> received message:', msg.event, msg.data)
+        const {subject,rating} = msg.data
+        const tx = cds.transaction(msg)
+        return tx.run (UPDATE(Books).set({rating}) .where ({ID:subject})) //.then (console.log)
+    })
+
+})
+
+
+// FIXME: pls remove this...
+process.env.destinations = JSON.stringify([{
+    name: 'reviewsDest',
+    url: 'http://localhost:4005/reviews',
+    username: 'dummy',
+    password: 'dummy'
+}])