SELECTION-SCREEN BEGIN OF BLOCK B1 WITH FRAME TITLE TEXT-001.
PARAMETERS    : P_FOLDER  TYPE STRING LOWER CASE DEFAULT 'C:\'.
SELECTION-SCREEN END OF BLOCK B1.

 

AT SELECTION-SCREEN ON VALUE-REQUEST FOR P_FOLDER.
  CALL METHOD CL_GUI_FRONTEND_SERVICES=>DIRECTORY_BROWSE
    CHANGING
      SELECTED_FOLDER      = P_FOLDER
    EXCEPTIONS
      CNTL_ERROR           = 1
      ERROR_NO_GUI         = 2
      NOT_SUPPORTED_BY_GUI = 3
      OTHERS               = 4.
  IF SY-SUBRC <> 0.
    MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
               WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
  ENDIF.  

Recently i was asked to how to link a pdf to the portal front.
Well It was like 4 years ago i did this and guess what i almost forget. But thanks to Chin Yoon Chan
I kind of relearn back.

Will explain in a brief and high detail way.
1. create a BSP in tcode SE80
2. create the html content (well optional)
3. import object mime (this time is a pdf)
4. create and bsp iview (you can see in the image attached)
5. link the start page to the EXACT location of your mime
6. As normal portal change
link iview to page
link pageto workset
link workset to role
configure img to reflect in the sub area (optional)