Swift

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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func chilkatTest() {
    var success: Bool = false

    //  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.

    let sftp = CkoSFtp()!

    //  Connect, authenticate, and initialize the SFTP subsystem.
    var port: Int = 22
    success = sftp.connect(hostname: "sftp.example.com", port: port)
    if success == false {
        print("\(sftp.lastErrorText!)")
        return
    }

    //  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.
    var password: String? = "mySshPassword"

    success = sftp.authenticatePw(login: "mySshLogin", password: password)
    if success == false {
        print("\(sftp.lastErrorText!)")
        return
    }

    success = sftp.initializeSftp()
    if success == false {
        print("\(sftp.lastErrorText!)")
        return
    }

    //  When followLinks is true, a symbolic link is followed and the target's type is returned.
    var followLinks: Bool = true
    var result: Int = sftp.fileExists(remotePath: "subdir/report.pdf", followLinks: followLinks).intValue

    //  Interpret the return value.
    if result == -1 {
        print("\(sftp.lastErrorText!)")
        return
    }

    if result == 0 {
        print("The path does not exist.")
    }

    if result == 1 {
        print("A regular file exists.")
    }

    if result == 2 {
        print("A directory exists.")
    }

    //  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.

    sftp.disconnect()

}