Improvements for Supplier replication

suppliers/monkey-patch.js

@@ -0,0 +1,38 @@
+const deploy = require("@sap/cds/lib/deploy");
+
+const DEBUG = (...args) => console.log(...args);
+
+deploy.exclude_external_entities_in = function (csn, _bound) {
+  // NOSONAR
+  for (let [each, { service = each, model, credentials }] of Object.entries(
+    cds.requires
+  )) {
+    if (!model) continue; //> not for internal services like cds.requires.odata
+    if (_bound && !credentials) continue;
+    DEBUG && DEBUG("excluding external entities for", service, "...");
+    const prefix = service + ".";
+    for (let each in csn.definitions) {
+      const def = csn.definitions[each];
+      if (def["@cds.persistence.table"] === true) continue;
+      if (each.startsWith(prefix)) {
+        DEBUG && DEBUG("excluding external entity", each);
+        _exclude(each);
+      }
+    }
+  }
+  return csn;
+
+  function _exclude(each) {
+    const def = csn.definitions[each];
+    if (def.kind !== "entity") return;
+    def["@cds.persistence.skip"] = true;
+    // propagate to all views...
+    for (let other in csn.definitions) {
+      const d = csn.definitions[other];
+      // do not exclude replica table
+      if (d["@cds.persistence.table"] === true) continue;
+      const p = (d.query && d.query.SELECT) || d.projection;
+      if (p && p.from.ref && p.from.ref[0] === each) _exclude(other);
+    }
+  }
+};

suppliers/requests.http

@@ -0,0 +1,27 @@
+
+@server = http://localhost:4004
+@authAlice = Authorization: Basic alice:
+
+PUT {{server}}/api-business-partner/A_BusinessPartner('ACME')
+Content-Type: application/json
+
+{
+    "BusinessPartnerFullName": "Alice Changed"
+}
+
+###
+
+PATCH {{server}}/admin/Books(201)
+{{authAlice}}
+Content-Type: application/json
+
+{
+    "supplier_ID": "PNG"
+}
+
+
+
+###
+
+GET {{server}}/admin/Books?$top=11&$expand=supplier
+{{authAlice}}

suppliers/server.js

@@ -1,3 +1,6 @@
 const cds = require ('@sap/cds')
+
+require('./monkey-patch');
+
 cds.once('served', require('./srv/mashup'))
 module.exports = cds.server

suppliers/srv/external/API_BUSINESS_PARTNER.js

@@ -0,0 +1,10 @@
+const cds = require('@sap/cds');
+
+module.exports = cds.service.impl(function (srv) {
+  const { A_BusinessPartner } = this.entities;
+
+  srv.after('UPDATE', A_BusinessPartner, data => {
+    console.log(`>>> BusinessPartner updated ${data.BusinessPartner}`);
+    srv.emit("BusinessPartners/Changed", { businessPartners: [ data.BusinessPartner ] });
+  });
+});

suppliers/srv/mashup.cds

@@ -16,10 +16,22 @@ extend service S4 with {
     //    CityName as name
     // }
 
+    // to_BusinessPartnerAddress
+
     // REVISIT: following is not supported so far in cqn2odata...
     // to_BusinessPartnerAddress.CityCode as city,
     // to_BusinessPartnerAddress.CityName as city_name,
   }
+
+
+  // REVISIT: Alternative idea to use a specific replication view, but request data from
+  // a different view and manual map values.
+  // entity ReplicatedSuppliers as projection on Suppliers {
+  //   ID,
+  //   name,
+  //   to_BusinessPartnerAddress.CityCode as city,
+  //   to_BusinessPartnerAddress.CityName as city_name
+  // }
 }
 
 

suppliers/srv/mashup.js

@@ -23,13 +23,21 @@ module.exports = async()=>{ // called by server.js
     })
 
     // Replicate Supplier data when edited Books have suppliers
-    admin.on (['CREATE','UPDATE'], 'Books', ({data:{supplier}}, next) => {
+    admin.on (['CREATE','UPDATE'], 'Books', async ({data:{supplier_ID: supplierId}}, next) => {
       // Using Promise.all(...) to parallelize local write, i.e. next(), and replication
-      if (supplier) return Promise.all ([ next(), async()=>{
+
-        let replicated = await db.exists (Suppliers, supplier)
+      /*
-        if (!replicated) await replicate (supplier, 'initial')
+      // ERROR: Reference integrity is violated for association "supplier"
+      if (supplierId) return Promise.all ([ next(), async()=>{
+        let replicated = await db.exists (Suppliers, supplierId)
+        if (!replicated) await replicate (supplierId, 'initial')
       }])
       else return next() //> don't forget to pass down the interceptor stack
+      */
+
+      let replicated = await db.exists (Suppliers, supplierId);
+      if (!replicated) await replicate (supplierId, 'initial');
+      return next();
     })
 
   })
@@ -47,7 +55,10 @@ module.exports = async()=>{ // called by server.js
    */
   async function replicate (IDs,_initial) {
     if (!Array.isArray(IDs)) IDs = [ IDs ]
-    let suppliers = await S4bupa.read (Suppliers).where('ID in',IDs)
+    // TODO: Doesn't work when running in same process with mocked API_BUSINESS_PARTNER
+
+    let suppliers = await S4bupa.read (Suppliers).where(...([[]].concat(IDs).reduce( (where, id, index ) => { where.push(`${index>1 ? "OR ":""}ID = `, id); return where })));
+    //let suppliers = await S4bupa.read (Suppliers).where('ID in',IDs)
     if (_initial) return db.insert (suppliers) .into (Suppliers) //> using bulk insert
     else return Promise.all(suppliers.map ( //> parallelizing updates
       each => db.update (Suppliers,each.ID) .with (each)