Swift

Detect End-of-File on a Remote SFTP File

Demonstrates the Chilkat SFtp.Eof method, which returns whether the most recent read for a handle received the SFTP end-of-file status. The only argument is the handle. This example reads until Eof is true.

Background: The timing here is worth understanding: reading exactly through the final byte does not immediately set EOF. The next read succeeds, returns zero bytes, sets the status to SSH_FX_EOF, and only then does Eof report true. That is why the loop tests Eof after each read rather than assuming a short read means the end — a short read can also just be the server returning less than requested.

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func chilkatTest() {
    var success: Bool = false

    //  Demonstrates the SFtp.Eof method, which returns whether the most recent read for a handle
    //  received the SFTP end-of-file status.  The only argument is the handle.

    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
    }

    var handle: String? = sftp.openFile(filename: "subdir/data.txt", access: "readOnly", createDisp: "openExisting")
    if sftp.lastMethodSuccess == false {
        print("\(sftp.lastErrorText!)")
        return
    }

    //  Read until Eof reports the end of the file.  Note that reading exactly through the final byte
    //  does not set EOF; the next read returns zero bytes and then Eof becomes true.
    let sbContent = CkoStringBuilder()!
    var chunkSize: Int = 4096
    var reading: Bool = true
    while reading {
        var chunk: String? = sftp.readFileText(sftpHandle: handle, numBytes: chunkSize, charset: "utf-8")
        if sftp.lastReadFailed(sftpHandle: handle) {
            print("\(sftp.lastErrorText!)")
            return
        }

        sbContent.append(value: chunk)
        reading = !sftp.eof(sftpHandle: handle)
    }

    success = sftp.closeHandle(sftpHandle: handle)
    if success == false {
        print("\(sftp.lastErrorText!)")
        return
    }

    print("\(sbContent.getAsString()!)")

    sftp.disconnect()

}