Homelab, Linux, JS & ABAP (~˘▾˘)~
 

Month: May 2023

JavaScript / nodejs

[nodejs] Create buffer from stream

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Using a promise

const streamToBuffer= async () => {
        return new Promise(function (resolve, reject) {
                const chunks = []
                stream.on('data', chunk => chunks.push(chunk))
                stream.on('end', () => resolve(Buffer.concat(chunks)))
                stream.on("error", err => reject(err))
        })
}
const buffer = await streamToBuffer()

A stream is also iterable (see here), so you can also use for await...of (example)

        const chunks = []
        for await (const chunk of stream) {
            chunks.push(chunk)
        }
        const buffer = Buffer.concat(chunks)
CAP

[CAP] CQL Expand Composition / Deep read

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In the documentation they always use a star in string literals like this o => o.`*` to select all fields, but when running this it always failed. However, after some tests I found that this format works with brackets o => o.('*')

https://cap.cloud.sap/docs/guides/providing-services/#–-deep-read

entity myEntity: cuid, managed {
    field1          : String;
    comp            : Composition of one myComposition;
}
 
aspect myComposition: cuid, managed {
    myCompField: String;
}

        const result = await SELECT.from(myEntity)
            .columns(e => {
                e('*')
                e.comp(c => c.myCompField) //expand composition, but only select 'myCompField'
            })

Update 14.09.2023: is now fixed (#)

CAP

[CAP] CQL Deep Update

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A Composition of one can be updated via the Parent Entity, like we would do it, when dealing with an Association to one. 

entity myEntity: cuid, managed {
    field1          : String;
    comp            : Composition of one myComposition;
}

aspect myComposition: cuid, managed {
    myCompField: String;
}

            const { myEntity } = srv.entities
            const EntityComposition = srv.entities['myEntity.myComposition'] // composition

            srv.after('CREATE', EntityComposition , async (comp, req) => {
                await UPDATE(myEntity, comp.ID)
                    .set({
                      comp : [{ myCompField: 'test' }]
                    })
            })

A Composition of many must be updated via the actual Composition Entity.

entity myEntity: cuid, managed {
    field1          : String;
    comp            : Composition to many myComposition;
}

aspect myComposition: cuid, managed {
    myCompField: String;
}

    const EntityComposition = srv.entities['myEntity.myComposition'] // composition

    srv.after('CREATE', EntityComposition , async (comp, req) => {
        await UPDATE(EntityComposition, { up__ID: comp.up__ID, ID: comp.ID }).set({ myCompField: 'test' })
    })