BOPF Action exporting parameter not accepting variable length Strings for Base64 file

[sainathmalireddi76]

Hi,
I have a requirement to send a Base64 encoding data( converted from internal table ) to frontend using BOPF Action.
I tried using Variable length String in Exporting Type but i am facing error like Exporting parameter structure yyyyy_s of action xxxxx is not a flat structure .
Can anyone please help me in finding the correct way to send a String type to frontend using BOPF Action.

Thanks in Advance

[Sandra_Rossi]

I don't know BOPF and I won't help much to say that from ABAP perspective, it's correct that a structure with at least one String or XString component is not Flat, it's Deep, because String/XString are Deep types.

I searched:

BOPF Exporting parameter structure is not a flat structure site:sap.com

which proposed this link, maybe the answer will help you: Create Fiori app using CDS with BOPF - (BOPF Action is not retrieved in the Gateway service) | SAP C...