Hi Everyone – My Motivation for Writing This
I recently worked on a requirement where users were uploading and processing files in an ABAP program. During testing, I noticed that many errors occurred simply because the file path was either incorrect or pointing to the wrong location (local system vs SAP application server).
Since this is a common challenge—especially in data migration and background processing—I decided to document a clean and reusable approach.
I prepared this post with the help of a generative AI tool, but all code, explanations, and examples reflect my own experience on an SAP S/4HANA system.
Why Validating File Paths Matters
Before reading the file, ABAP must know where it is located:
File Uploads: Detect if the user is picking a file from their PC.
File Export: Decide whether to save on SAP server or local desktop.
Batch/Background Jobs: Only application-server paths are allowed.
Data Migration: Large files usually reside on the SAP server.
File Processing: Avoid runtime errors caused by invalid paths.
Approach
In ABAP, local (presentation server) files are handled through CL_GUI_FRONTEND_SERVICES, while server files use OPEN DATASET.
So the idea is:
Check if the path exists on the local system.
If not, try accessing it as an application server path.
If both fail → invalid path.
Example Program Code :
REPORT zsap_val_path.
DATA: lv_file_exist TYPE abap_bool VALUE abap_false,
lv_dir_exist TYPE abap_bool VALUE abap_false,
file_type TYPE char10,
file_path TYPE string.
SELECTION-SCREEN BEGIN OF BLOCK b2 WITH FRAME TITLE TEXT-002.
PARAMETERS: p_fname TYPE string LOWER CASE.
SELECTION-SCREEN END OF BLOCK b2.
“——————————————————-
” F4 Help – Let user browse directories on local machine
“——————————————————-
AT SELECTION-SCREEN ON VALUE-REQUEST FOR p_fname.
CALL METHOD cl_gui_frontend_services=>directory_browse
CHANGING
selected_folder = p_fname
EXCEPTIONS
cntl_error = 1
error_no_gui = 2
not_supported_by_gui = 3
OTHERS = 4.
IF sy-subrc <> 0.
MESSAGE ‘File path not selected’ TYPE ‘E’ DISPLAY LIKE ‘W’.
ENDIF.
“——————————————————-
” Validate Path
“——————————————————-
file_path = p_fname.
TRY.
“Check if it’s a LOCAL file
cl_gui_frontend_services=>file_exist(
EXPORTING file = file_path
RECEIVING result = lv_file_exist ).
“If not a file, check if it’s a LOCAL directory
IF lv_file_exist = abap_false.
cl_gui_frontend_services=>directory_exist(
EXPORTING directory = file_path
RECEIVING result = lv_dir_exist ).
ENDIF.
CATCH cx_root INTO DATA(lx_root).
lv_file_exist = abap_false.
lv_dir_exist = abap_false.
ENDTRY.
“——————————————————-
” Determine: Local (LOC) or Application Server (APP)
“——————————————————-
IF lv_file_exist = abap_true OR lv_dir_exist = abap_true.
file_type = ‘LOC’.
ELSE.
“Try Application Server
OPEN DATASET file_path FOR INPUT IN BINARY MODE.
IF sy-subrc = 0.
CLOSE DATASET file_path.
file_type = ‘APP’.
ELSE.
MESSAGE ‘Invalid path. Enter a valid LOCAL or Application Server path.’
TYPE ‘E’.
EXIT.
ENDIF.
ENDIF.
“——————————————————-
” Output
“——————————————————-
CASE file_type.
WHEN ‘APP’.
WRITE: ‘APPLICATION SERVER PATH’.
WHEN ‘LOC’.
WRITE: ‘LOCAL FILE PATH (PRESENTATION SERVER)’.
WHEN OTHERS.
WRITE: ‘UNKNOWN FILE TYPE’.
ENDCASE.
From my experience, users often assume a path will behave the same in dialog and background modes—but that’s not true.
Always remember:
Local files work only in GUI mode
Background jobs can only access application-server paths
This validation step saves a lot of debugging time later.
Thank You !!
Hi Everyone – My Motivation for Writing ThisI recently worked on a requirement where users were uploading and processing files in an ABAP program. During testing, I noticed that many errors occurred simply because the file path was either incorrect or pointing to the wrong location (local system vs SAP application server).Since this is a common challenge—especially in data migration and background processing—I decided to document a clean and reusable approach.I prepared this post with the help of a generative AI tool, but all code, explanations, and examples reflect my own experience on an SAP S/4HANA system.Why Validating File Paths MattersBefore reading the file, ABAP must know where it is located:File Uploads: Detect if the user is picking a file from their PC.File Export: Decide whether to save on SAP server or local desktop.Batch/Background Jobs: Only application-server paths are allowed.Data Migration: Large files usually reside on the SAP server.File Processing: Avoid runtime errors caused by invalid paths.ApproachIn ABAP, local (presentation server) files are handled through CL_GUI_FRONTEND_SERVICES, while server files use OPEN DATASET.So the idea is:Check if the path exists on the local system.If not, try accessing it as an application server path.If both fail → invalid path.Example Program Code :REPORT zsap_val_path.
DATA: lv_file_exist TYPE abap_bool VALUE abap_false,
lv_dir_exist TYPE abap_bool VALUE abap_false,
file_type TYPE char10,
file_path TYPE string.
SELECTION-SCREEN BEGIN OF BLOCK b2 WITH FRAME TITLE TEXT-002.
PARAMETERS: p_fname TYPE string LOWER CASE.
SELECTION-SCREEN END OF BLOCK b2.
“——————————————————-
” F4 Help – Let user browse directories on local machine
“——————————————————-
AT SELECTION-SCREEN ON VALUE-REQUEST FOR p_fname.
CALL METHOD cl_gui_frontend_services=>directory_browse
CHANGING
selected_folder = p_fname
EXCEPTIONS
cntl_error = 1
error_no_gui = 2
not_supported_by_gui = 3
OTHERS = 4.
IF sy-subrc <> 0.
MESSAGE ‘File path not selected’ TYPE ‘E’ DISPLAY LIKE ‘W’.
ENDIF.
“——————————————————-
” Validate Path
“——————————————————-
file_path = p_fname.
TRY.
“Check if it’s a LOCAL file
cl_gui_frontend_services=>file_exist(
EXPORTING file = file_path
RECEIVING result = lv_file_exist ).
“If not a file, check if it’s a LOCAL directory
IF lv_file_exist = abap_false.
cl_gui_frontend_services=>directory_exist(
EXPORTING directory = file_path
RECEIVING result = lv_dir_exist ).
ENDIF.
CATCH cx_root INTO DATA(lx_root).
lv_file_exist = abap_false.
lv_dir_exist = abap_false.
ENDTRY.
“——————————————————-
” Determine: Local (LOC) or Application Server (APP)
“——————————————————-
IF lv_file_exist = abap_true OR lv_dir_exist = abap_true.
file_type = ‘LOC’.
ELSE.
“Try Application Server
OPEN DATASET file_path FOR INPUT IN BINARY MODE.
IF sy-subrc = 0.
CLOSE DATASET file_path.
file_type = ‘APP’.
ELSE.
MESSAGE ‘Invalid path. Enter a valid LOCAL or Application Server path.’
TYPE ‘E’.
EXIT.
ENDIF.
ENDIF.
“——————————————————-
” Output
“——————————————————-
CASE file_type.
WHEN ‘APP’.
WRITE: ‘APPLICATION SERVER PATH’.
WHEN ‘LOC’.
WRITE: ‘LOCAL FILE PATH (PRESENTATION SERVER)’.
WHEN OTHERS.
WRITE: ‘UNKNOWN FILE TYPE’.
ENDCASE.From my experience, users often assume a path will behave the same in dialog and background modes—but that’s not true.Always remember: Local files work only in GUI mode Background jobs can only access application-server pathsThis validation step saves a lot of debugging time later.Thank You !! Read More Technology Blog Posts by Members articles
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