@sap/cds/libx/_runtime/common/utils/streamProp.js

SAP Cloud Application Programming Model - CDS for Node.js

const { ensureNoDraftsSuffix, ensureUnlocalized } = require('./draft')
const { isDuplicate } = require('./rewriteAsterisks')

const resolveMediaTypeAnnotation = type => {
  if (!type) {
    return null
  }
  if (typeof type === 'object' && type.ref && type.ref[0] === '$self') {
    return { ref: type.ref.slice(1) }
  }
  if (typeof type === 'object' && type.ref) {
    return { ref: type.ref }
  }
  if (typeof type === 'object' && type['=']) {
    return { ref: [type['='].replaceAll(/\./g, '_')] }
  }
  return { val: type }
}

const _addColumn = (name, mediaType, columns, url, target) => {
  if (mediaType.ref && target.elements[mediaType?.ref?.[0]]?.virtual) return
  const col = {
    xpr: [
      'case',
      'when',
      { ref: [name] },
      '=',
      { val: null },
      'then',
      { val: null },
      'else',
      { func: 'coalesce', args: [mediaType, { val: 'application/octet-stream' }] },
      'end'
    ],
    as: `${name}@odata.mediaContentType`
  }

  if (!columns.find(isDuplicate(col))) columns.push(col)

  if (url) {
    const ref = {
      ref: [name],
      as: `${name}@odata.mediaReadLink`
    }
    if (!columns.find(isDuplicate(ref))) columns.push(ref)
  }
}

const handleStreamProperties = (target, columns, model) => {
  if (!target || !model || !columns) return

  let index = columns.length
  while (index--) {
    const col = columns[index]
    const name = col.ref && col.ref[col.ref.length - 1]
    const element = name && target.elements[name]
    const type = element && element.type
    const mediaType = resolveMediaTypeAnnotation(element?.['@Core.MediaType'])

    const ignoreMediaType = mediaType && element['@Core.IsURL']

    if (col.ref && (type === 'cds.LargeBinary' || (mediaType && !ignoreMediaType))) {
      if (mediaType && !element.virtual) _addColumn(name, mediaType, columns, element['@Core.IsURL'], target)
      columns.splice(index, 1)
    } else if (col.expand && col.ref) {
      const tgt = target.elements[col.ref] && target.elements[col.ref].target
      tgt && handleStreamProperties(model.definitions[ensureUnlocalized(ensureNoDraftsSuffix(tgt))], col.expand, model)
    }
  }
}

module.exports = { handleStreamProperties }