Visual FoxPro

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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LOCAL lnSuccess
LOCAL loSftp
LOCAL lnPort
LOCAL lcPassword
LOCAL lnFollowLinks
LOCAL lnResult

lnSuccess = 0

*  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.

loSftp = CreateObject('Chilkat.SFtp')

*  Connect, authenticate, and initialize the SFTP subsystem.
lnPort = 22
lnSuccess = loSftp.Connect("sftp.example.com",lnPort)
IF (lnSuccess = 0) THEN
    ? loSftp.LastErrorText
    RELEASE loSftp
    CANCEL
ENDIF

*  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.
lcPassword = "mySshPassword"

lnSuccess = loSftp.AuthenticatePw("mySshLogin",lcPassword)
IF (lnSuccess = 0) THEN
    ? loSftp.LastErrorText
    RELEASE loSftp
    CANCEL
ENDIF

lnSuccess = loSftp.InitializeSftp()
IF (lnSuccess = 0) THEN
    ? loSftp.LastErrorText
    RELEASE loSftp
    CANCEL
ENDIF

*  When followLinks is 1, a symbolic link is followed and the target's type is returned.
lnFollowLinks = 1
lnResult = loSftp.FileExists("subdir/report.pdf",lnFollowLinks)

*  Interpret the return value.
IF (lnResult = -1) THEN
    ? loSftp.LastErrorText
    RELEASE loSftp
    CANCEL
ENDIF

IF (lnResult = 0) THEN
    ? "The path does not exist."
ENDIF

IF (lnResult = 1) THEN
    ? "A regular file exists."
ENDIF

IF (lnResult = 2) THEN
    ? "A directory exists."
ENDIF

*  Other possible values: 3 = symbolic link (only when followLinks is 0), 4 = special
*  entry, 5 = unknown, 6 = socket, 7 = character device, 8 = block device, 9 = FIFO.

loSftp.Disconnect()

RELEASE loSftp