Gateway for simple function module

Hi there,

my background is ABAP and I've now started development with SAPUI5.

My scenario:

I want to write a simple SAPUI5 application allowing to change a user password.

Therefore I've created a RFC-enabled function module 'ZBC_USER_SET_NEW_PASSWORD' in the backend system:

FUNCTION zbc_user_set_new_password.

*"----------------------------------------------------------------------

*"*"Local Interface:

*"  IMPORTING

*"     VALUE(I_UNAME) TYPE  SYUNAME

*"     VALUE(I_PASSWORD) TYPE  STRINGVAL

*"----------------------------------------------------------------------

 

   DATA:

     ls_return             TYPE bapiret2,

     lt_return             TYPE STANDARD TABLE OF bapiret2.

 

   CALL FUNCTION 'BAPI_USER_CHANGE'

     EXPORTING

       username  = i_uname

       password  = i_password

       passwordx = abap_true

     TABLES

       return    = lt_return.

 

   READ TABLE lt_return INTO ls_return

     WITH KEY

       type = 'E'.

   IF sy-subrc IS INITIAL.

*     Error occured

 

 

     EXIT.

   ENDIF.

 

ENDFUNCTION.

Now I would like to call that FM from a SAPUI5 application running on the same ABAP server.

I've tried to create a gateway service that only calls this function module, but I'm struggling with the GetEntitySet and GetEntity methods.

What is the easiest way to create a gateway service to call the above listed function module?

Please note that I don't want to retrieve any data. I just would like to send a new password to the backend system.

If gateway is not appropriate for this, would it be better to expose the FM as web service and directly call it via SOAP request?

Thanks in advance.