Lianja

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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llSuccess = .F.

//  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("CkSFtp")

//  Connect, authenticate, and initialize the SFTP subsystem.
lnPort = 22
llSuccess = loSftp.Connect("sftp.example.com",lnPort)
if (llSuccess = .F.) then
    ? loSftp.LastErrorText
    release loSftp
    return
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"

llSuccess = loSftp.AuthenticatePw("mySshLogin",lcPassword)
if (llSuccess = .F.) then
    ? loSftp.LastErrorText
    release loSftp
    return
endif

llSuccess = loSftp.InitializeSftp()
if (llSuccess = .F.) then
    ? loSftp.LastErrorText
    release loSftp
    return
endif

//  When followLinks is .T., a symbolic link is followed and the target's type is returned.
llFollowLinks = .T.
lnResult = loSftp.FileExists("subdir/report.pdf",llFollowLinks)

//  Interpret the return value.
if (lnResult = -1) then
    ? loSftp.LastErrorText
    release loSftp
    return
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 .F.), 4 = special
//  entry, 5 = unknown, 6 = socket, 7 = character device, 8 = block device, 9 = FIFO.

loSftp.Disconnect()


release loSftp