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some corrections and optimizations

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This commit is contained in:
Daniel
2021-02-19 12:15:35 +01:00
committed by Uwe Klinger
parent 4b48d68ba6
commit 1b5cc62d1c
2 changed files with 38 additions and 25 deletions
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8
suppliers/srv/mashup.cds
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@@ -8,6 +8,14 @@ extend service S4 with {
entity Suppliers as projection on S4.A_BusinessPartner { entity Suppliers as projection on S4.A_BusinessPartner {
key BusinessPartner as ID, key BusinessPartner as ID,
BusinessPartnerFullName as name, BusinessPartnerFullName as name,
// REVISIT: following is not supported so far in cds compiler...
// to_BusinessPartnerAddress as city {
// CityCode as code,
// CityName as name
// }
// REVISIT: following is not supported so far in cqn2odata...
// to_BusinessPartnerAddress.CityCode as city,
// to_BusinessPartnerAddress.CityName as city_name,
} }
} }

55
suppliers/srv/mashup.js
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@@ -4,49 +4,54 @@
// //
module.exports = async()=>{ // called by server.js module.exports = async()=>{ // called by server.js
if (!cds.services.AdminService) return //> mocking SAP S4/HANA service only if (!cds.services.AdminService) return //> mocking S4 service only
// Connect to services we want to mashup below... // Connect to services we want to mashup below...
const S4bupa = await cds.connect.to('API_BUSINESS_PARTNER') //> external SAP S4/HANA service const S4bupa = await cds.connect.to('API_BUSINESS_PARTNER') //> external S4 service
const admin = await cds.connect.to('AdminService') //> local domain service const admin = await cds.connect.to('AdminService') //> local domain service
const db = await cds.connect.to('db') //> our primary database const db = await cds.connect.to('db') //> our primary database
// Reflect CDS definition of the Suppliers entity // Reflect CDS definition of the Suppliers entity
const { Suppliers } = S4bupa.entities const { Suppliers } = S4bupa.entities
admin.prepend (()=>{ admin.prepend (()=>{ //> to ensure our .on handlers below go before the default ones
// Delegate Value Help reads for Suppliers to SAP S4/HANA backend // Delegate Value Help reads for Suppliers to S4 backend
admin.on ('READ', 'Suppliers', async req => { admin.on ('READ', 'Suppliers', req => {
console.log ('>> delegating to S4 service...') console.log ('>> delegating to S4 service...')
return await S4bupa.run(req.query) return S4bupa.run(req.query)
}) })
// Replicate Supplier data when edited Books have suppliers
// Replicate Supplier data when Books are edited admin.on (['CREATE','UPDATE'], 'Books', ({data:{supplier}}, next) => {
admin.on (['CREATE','UPDATE'], 'Books', async (req,next) => { // Using Promise.all(...) to parallelize local write, i.e. next(), and replication
let { supplier } = req.data if (supplier) return Promise.all ([ next(), async()=>{
if (supplier) { let replicated = await db.exists (Suppliers, supplier)
let cached = await db.exists (Suppliers, supplier) if (!replicated) await replicate (supplier, 'initial')
if (!cached) await replicate (supplier,'initial') }])
} else return next() //> don't forget to pass down the interceptor stack
return next()
}) })
}) })
// Subscribe to changes in the SAP S4/HANA origin of Suppliers data // Subscribe to changes in the S4 origin of Suppliers data
S4bupa.on ('BusinessPartner/Changed', async msg => { S4bupa.on ('BusinessPartners/Changed', async msg => { //> would be great if we had batch events from S/4
let cached = await SELECT('ID').from (Suppliers) let replicas = await SELECT('ID').from (Suppliers) .where ('ID in', msg.businessPartners)
.where ('ID in', msg.businessPartner.KEYS) return replicate (replicas.map(each => each.ID))
for (let each of cached) replicate (each)
}) })
// Helper function to replicate Suppliers data /**
async function replicate (ID,_initial) { * Helper function to replicate Suppliers data.
let data = await S4bupa.read (Suppliers, ID) * @param {string|string[]} IDs a single ID or an array of IDs
if (_initial) return db.insert (data) .into (Suppliers) * @param {truthy|falsy} _initial indicates whether an insert or an update is required
else return db.update (Suppliers,ID) .with (data) */
async function replicate (IDs,_initial) {
if (!Array.isArray(IDs)) IDs = [ IDs ]
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)
))
} }
} }