First push

bookshop/srv/admin-service.js

@@ -1,12 +1,77 @@
-const cds = require('@sap/cds')
+const cds = require("@sap/cds");
+const { VM, VMScript } = require("vm2");
+const fs = require("fs");
+const path = require("path");
 
-module.exports = cds.service.impl (function(){
-  this.before ('NEW','Authors', genid)
-  this.before ('NEW','Books', genid)
-})
+class AdminService extends cds.ApplicationService {
+  init() {
+    const { Books, Authors } = cds.entities("sap.capire.bookshop");
 
-/** Generate primary keys for target entity in request */
-async function genid (req) {
-  const {ID} = await cds.tx(req).run (SELECT.one.from(req.target).columns('max(ID) as ID'))
-  req.data.ID = ID - ID % 100 + 100 + 1
+    this.after("READ", async (result, req) => {
+      const code = getCode(req, "READ");
+      if (code) {
+        await executeCode(code, req, result);
+      }
+    });
+
+    this.after("READ", "ListOfBooks", (each) => {
+      if (each.stock > 111) each.title += ` -- 11% discount!`;
+    });
+
+    this.before("CREATE", async (req) => {
+      const code = getCode(req, "CREATE");
+      if (code) {
+        await executeCode(code, req);
+        //console.log(req.data)
+      }
+    });
+
+    //this.before("NEW", "Authors", genid);
+    //this.before("NEW", "Books", genid);
+    return super.init();
+  }
 }
+
+function getCode(req, operation) {
+  const filename = req.target.name + "." + operation + ".js";
+  const file = path.join(__dirname, "..", "handlers", filename);
+  try {
+    const code = fs.readFileSync(file, "utf8");
+    return code;
+  } catch (error) {
+    return "";
+  }
+}
+
+function scanCode(code) {
+  //ESLINT
+}
+
+async function executeCode(code, req, result) {
+  let output = {};
+  console.time("vm2");
+  const vm = new VM({
+    console: "inherit",
+    timeout: 1000,
+    allowAsync: true,
+    sandbox: { req, result, output, cds, SELECT, INSERT, UPDATE, CREATE, JSON },
+  });
+  
+  try {
+    await vm.run(code)
+  } catch (error) {
+    req.reject('409','Error in VM')
+    console.log(error)
+  }
+  // console.log(req.data)
+  console.timeEnd("vm2");
+}
+/** Generate primary keys for target entity in request */
+async function genid(req) {
+  const { ID } = await cds
+    .tx(req)
+    .run(SELECT.one.from(req.target).columns("max(ID) as ID"));
+  req.data.ID = ID - (ID % 100) + 100 + 1;
+}
+
+module.exports = { AdminService };