SQL Server

Connect to an SFTP Server Through a Jump Host

Demonstrates the Chilkat SFtp.ConnectThroughSsh method, which connects to an SFTP server through an already connected and authenticated Ssh object. The first argument is the jump-host Ssh object, and the second and third are the destination hostname and port.

Background: This is the "jump host" (bastion) pattern: the application connects to a reachable gateway, then tunnels onward to an SFTP server that is only accessible from inside the network. Each hop authenticates separately with its own credentials. The result is a normal SFtp object — still requiring its own authentication and InitializeSftp — that happens to be routed through the first connection.

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-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

    --  Demonstrates the SFtp.ConnectThroughSsh method, which connects to an SFTP server through an
    --  already connected and authenticated Ssh object (a jump host).  The 1st argument is the Ssh
    --  object, and the 2nd and 3rd are the destination hostname and port.

    DECLARE @sshJump int
    EXEC @hr = sp_OACreate 'Chilkat.Ssh', @sshJump OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    --  Connect and authenticate to the jump host first.
    DECLARE @port int
    SELECT @port = 22
    EXEC sp_OAMethod @sshJump, 'Connect', @success OUT, 'jump.example.com', @port
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @sshJump, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @sshJump
        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.
    DECLARE @password nvarchar(4000)
    SELECT @password = 'mySshPassword'

    EXEC sp_OAMethod @sshJump, 'AuthenticatePw', @success OUT, 'myJumpLogin', @password
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @sshJump, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @sshJump
        RETURN
      END

    --  Connect to the SFTP server through the jump host.
    DECLARE @sftp int
    EXEC @hr = sp_OACreate 'Chilkat.SFtp', @sftp OUT

    EXEC sp_OAMethod @sftp, 'ConnectThroughSsh', @success OUT, @sshJump, 'sftp.internal.example.com', @port
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @sftp, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @sshJump
        EXEC @hr = sp_OADestroy @sftp
        RETURN
      END

    --  Authenticate to the SFTP server (its own credentials), then initialize SFTP.
    EXEC sp_OAMethod @sftp, 'AuthenticatePw', @success OUT, 'mySshLogin', @password
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @sftp, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @sshJump
        EXEC @hr = sp_OADestroy @sftp
        RETURN
      END

    EXEC sp_OAMethod @sftp, 'InitializeSftp', @success OUT
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @sftp, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @sshJump
        EXEC @hr = sp_OADestroy @sftp
        RETURN
      END

    PRINT 'Connected to the SFTP server through the jump host.'

    EXEC sp_OAMethod @sftp, 'Disconnect', NULL
    EXEC sp_OAMethod @sshJump, 'Disconnect', NULL

    EXEC @hr = sp_OADestroy @sshJump
    EXEC @hr = sp_OADestroy @sftp


END
GO