This system has maintenance concerns. 27
Server-side Data API calls (see Data API) are triggered on step save (see Posting Data) and are handled much like they are on the client. Such calls are made automatically only for document metadata. Results of sever-side calls are not written to the bucket and are therefore useful for data that the client should not be permitted to modify; it also allows data to be kept secret from the client.28
Data API results on the client can be mapped back to multiple bucket values; the server, however, has serious concerns with how data are propagated for data integrity and security reasons. Further, document metadata can be structured, unlike the Bucket which has a rigid matrix format (see Bucket). Therefore, the entire response is mapped into the parent field; defined return values are used only for filtering.
When a DataAPI request is made, it supercedes any previous requests that may still be pending for that same index.