58 lines
2.3 KiB
JavaScript
58 lines
2.3 KiB
JavaScript
////////////////////////////////////////////////////////////////////////////
|
|
//
|
|
// Mashing up provided and required services...
|
|
//
|
|
module.exports = async()=>{ // called by server.js
|
|
|
|
if (!cds.services.AdminService) return //> mocking S4 service only
|
|
|
|
// Connect to services we want to mashup below...
|
|
const S4bupa = await cds.connect.to('API_BUSINESS_PARTNER') //> external S4 service
|
|
const admin = await cds.connect.to('AdminService') //> local domain service
|
|
const db = await cds.connect.to('db') //> our primary database
|
|
|
|
// Reflect CDS definition of the Suppliers entity
|
|
const { Suppliers } = S4bupa.entities
|
|
|
|
admin.prepend (()=>{ //> to ensure our .on handlers below go before the default ones
|
|
|
|
// Delegate Value Help reads for Suppliers to S4 backend
|
|
admin.on ('READ', 'Suppliers', req => {
|
|
console.log ('>> delegating to S4 service...')
|
|
return S4bupa.run(req.query)
|
|
})
|
|
|
|
// Replicate Supplier data when edited Books have suppliers
|
|
admin.on (['CREATE','UPDATE'], 'Books', ({data:{supplier}}, 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')
|
|
}])
|
|
else return next() //> don't forget to pass down the interceptor stack
|
|
})
|
|
|
|
})
|
|
|
|
// Subscribe to changes in the S4 origin of Suppliers data
|
|
S4bupa.on ('BusinessPartners/Changed', async msg => { //> would be great if we had batch events from S/4
|
|
let replicas = await SELECT('ID').from (Suppliers) .where ('ID in', msg.businessPartners)
|
|
return replicate (replicas.map(each => each.ID))
|
|
})
|
|
|
|
/**
|
|
* Helper function to replicate Suppliers data.
|
|
* @param {string|string[]} IDs a single ID or an array of IDs
|
|
* @param {truthy|falsy} _initial indicates whether an insert or an update is required
|
|
*/
|
|
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)
|
|
))
|
|
}
|
|
|
|
}
|