DataFlex

Check if a Remote File or Directory Exists

Demonstrates the Chilkat SFtp.FileExists method, which checks a remote path and returns an integer describing what is there. The first argument is the remote path and the second (followLinks) selects whether a symbolic link is followed to its target. The return value is -1 on error, 0 if nothing exists, 1 for a file, 2 for a directory, 3 for a symbolic link, and higher values for special entry types.

Background: This returns more than a yes/no because "does it exist" usually comes with "and is it the kind of thing I expect" — a job that means to write a file should notice if a directory already occupies the path. The followLinks flag decides whether a symbolic link is reported as a link (3, only when not following) or transparently resolved to its target's type. Always handle the -1 case: it means the check itself failed, which is different from the path not existing.

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Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoSftp
    Integer iPort
    String sPassword
    Boolean iFollowLinks
    Integer iResult
    String sTemp1

    Move False To iSuccess

    //  Demonstrates the SFtp.FileExists method, which checks a remote path and returns an integer
    //  describing what is there.  The 1st argument is the remote path and the 2nd (followLinks)
    //  selects whether a symbolic link is followed to its target.

    Get Create (RefClass(cComChilkatSFtp)) To hoSftp
    If (Not(IsComObjectCreated(hoSftp))) Begin
        Send CreateComObject of hoSftp
    End

    //  Connect, authenticate, and initialize the SFTP subsystem.
    Move 22 To iPort
    Get ComConnect Of hoSftp "sftp.example.com" iPort To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSftp To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  Normally you would not hard-code the password in source.  You should instead obtain it
    //  from an interactive prompt, environment variable, or a secrets vault.
    Move "mySshPassword" To sPassword

    Get ComAuthenticatePw Of hoSftp "mySshLogin" sPassword To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSftp To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComInitializeSftp Of hoSftp To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSftp To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  When followLinks is True, a symbolic link is followed and the target's type is returned.
    Move True To iFollowLinks
    Get ComFileExists Of hoSftp "subdir/report.pdf" iFollowLinks To iResult

    //  Interpret the return value.
    If (iResult = -1) Begin
        Get ComLastErrorText Of hoSftp To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    If (iResult = 0) Begin
        Showln "The path does not exist."
    End

    If (iResult = 1) Begin
        Showln "A regular file exists."
    End

    If (iResult = 2) Begin
        Showln "A directory exists."
    End

    //  Other possible values: 3 = symbolic link (only when followLinks is False), 4 = special
    //  entry, 5 = unknown, 6 = socket, 7 = character device, 8 = block device, 9 = FIFO.

    Send ComDisconnect To hoSftp


End_Procedure