SQL Server

SSH Tunnel with Dynamic Port Forwarding

See more SSH Examples

Demonstrates how to start a background thread that runs a portable SSH tunnel w/ dynamic port forwarding that the foreground thread can use for establishing connections through an SSH tunnel. SQL Server

-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @iTmp0 int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

    -- This example assumes the Chilkat API to have been previously unlocked.
    -- See Global Unlock Sample for sample code.

    SELECT @success = 0

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

    DECLARE @sshHostname nvarchar(4000)
    SELECT @sshHostname = 'sftp.example.com'
    DECLARE @sshPort int
    SELECT @sshPort = 22

    -- Connect to an SSH server and establish the SSH tunnel:
    EXEC sp_OAMethod @tunnel, 'Connect', @success OUT, @sshHostname, @sshPort
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @tunnel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        RETURN
      END

    -- Authenticate with the SSH server via a login/password
    -- or with a public key.  
    -- This example demonstrates SSH password authentication.
    EXEC sp_OAMethod @tunnel, 'AuthenticatePw', @success OUT, 'mySshLogin', 'mySshPassword'
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @tunnel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        RETURN
      END

    -- Indicate that the background SSH tunnel thread will behave as a SOCKS proxy server
    -- with dynamic port forwarding:
    EXEC sp_OASetProperty @tunnel, 'DynamicPortForwarding', 1

    -- We may optionally require that connecting clients authenticate with our SOCKS proxy server.
    -- To do this, set an inbound username/password.  Any connecting clients would be required to 
    -- use SOCKS5 with the correct username/password.
    -- If no inbound username/password is set, then our SOCKS proxy server will accept both
    -- SOCKS4 and SOCKS5 unauthenticated connections.

    EXEC sp_OASetProperty @tunnel, 'InboundSocksUsername', 'chilkat123'
    EXEC sp_OASetProperty @tunnel, 'InboundSocksPassword', 'password123'

    -- Start the listen/accept thread to begin accepting SOCKS proxy client connections.
    -- Listen on port 1080.
    EXEC sp_OAMethod @tunnel, 'BeginAccepting', @success OUT, 1080
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @tunnel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        RETURN
      END

    -- Now that a background thread is running a SOCKS proxy server that forwards connections
    -- through an SSH tunnel, it is possible to use any Chilkat implemented protocol that is SOCKS capable,
    -- such as HTTP, POP3, SMTP, IMAP, FTP, etc.  The protocol may use SSL/TLS because the SSL/TLS
    -- will be passed through the SSH tunnel to the end-destination.  Also, any number of simultaneous
    -- connections may be routed through the SSH tunnel.

    -- For this example, let's do a simple HTTPS request:
    DECLARE @url nvarchar(4000)
    SELECT @url = 'https://www.ethereum.org/'

    DECLARE @http int
    EXEC @hr = sp_OACreate 'Chilkat.Http', @http OUT

    -- Indicate that the HTTP object is to use our portable SOCKS proxy/SSH tunnel running in our background thread.
    EXEC sp_OASetProperty @http, 'SocksHostname', 'localhost'
    EXEC sp_OASetProperty @http, 'SocksPort', 1080
    EXEC sp_OASetProperty @http, 'SocksVersion', 5
    EXEC sp_OASetProperty @http, 'SocksUsername', 'chilkat123'
    EXEC sp_OASetProperty @http, 'SocksPassword', 'password123'

    EXEC sp_OASetProperty @http, 'SendCookies', 1
    EXEC sp_OASetProperty @http, 'SaveCookies', 1
    EXEC sp_OASetProperty @http, 'CookieDir', 'memory'

    -- Do the HTTPS page fetch (through the SSH tunnel)
    DECLARE @html nvarchar(4000)
    EXEC sp_OAMethod @http, 'QuickGetStr', @html OUT, @url
    EXEC sp_OAGetProperty @http, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN
        EXEC sp_OAGetProperty @http, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        EXEC @hr = sp_OADestroy @http
        RETURN
      END

    -- Stop the background listen/accept thread:
    DECLARE @waitForThreadExit int
    SELECT @waitForThreadExit = 1
    EXEC sp_OAMethod @tunnel, 'StopAccepting', @success OUT, @waitForThreadExit
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @tunnel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        EXEC @hr = sp_OADestroy @http
        RETURN
      END

    -- Close the SSH tunnel (would also kick any remaining connected clients).
    EXEC sp_OAMethod @tunnel, 'CloseTunnel', @success OUT, @waitForThreadExit
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @tunnel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        EXEC @hr = sp_OADestroy @http
        RETURN
      END

    EXEC @hr = sp_OADestroy @tunnel
    EXEC @hr = sp_OADestroy @http


END
GO