[ABAP] OData – GET_STREAM implementation to return a PDF

  METHOD /iwbep/if_mgw_appl_srv_runtime~get_stream.

* This method get's called when a media file is queried with $value. A binary stream will be returned.

    TRY.
        DATA(file_id) = VALUE zfile_id( it_key_tab[ name = 'file_id' ]-value ).
      CATCH cx_sy_itab_line_not_found.
        RETURN. " leave here when no file_id provided
    ENDTRY.
  
    DATA(ls_file) = get_file( file_id ) " read your file you want to return (if it's not yet a binary stream, convert it)

    DATA(ls_stream) = VALUE ty_s_media_resource( value     = ls_file-value
                                                 mime_type = ls_file-mimetype ). " in my case it's 'application/pdf'

    " necessary to display the filename instead of $value in the viewer title
    TRY.
        " create pdf object
        DATA(lo_fp)     = cl_fp=>get_reference( ).
        DATA(lo_pdfobj) = lo_fp->create_pdf_object( connection = 'ADC' ).
        lo_pdfobj->set_document( pdfdata = ls_stream-value ).
        " set title
        lo_pdfobj->set_metadata( VALUE #( title = ls_file-filename ) ).
        lo_pdfobj->execute( ).
        " get pdf with title
        lo_pdfobj->get_document( IMPORTING pdfdata = ls_stream-value ).

      CATCH cx_fp_runtime_internal
            cx_fp_runtime_system
            cx_fp_runtime_usage INTO DATA(lo_fpex).
    ENDTRY.

    copy_data_to_ref( EXPORTING is_data = ls_stream
                      CHANGING  cr_data = er_stream ).

    " necessary for the pdf to be opened inline instead of a download (also sets the filename when downloaded)
    /iwbep/if_mgw_conv_srv_runtime~set_header( VALUE #( name  = 'content-disposition'
                                                        value = |inline; filename={ ls_file-filename }| ) ).

  ENDMETHOD

			const pdfViewer = new PDFViewer()
			pdfViewer.setSource("/sap/opu/odata/ZMY_SEVICE" + my_path + "/$value")  // my_path could be something like this "/PdfSet('file_id')"
			pdfViewer.setTitle("My PDFViewer Title") // title of the popup, not the viewer
			pdfViewer.open()