(SQL Server) WebSocket through SSH Tunnel

This example shows how to establish a WebSocket connection through an SSH tunnel. The WebSocket protocol communications will be encapsulated within an SSH tunnel.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

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

    -- --------------------------------------------------
    -- This example borrows the code from the REST through SSH Tunnel example.
    -- We first use the Chilkat Socket object to establish a connection to the WebSocket server through an SSH Tunnel.
    -- Next, the Rest object uses the Socket object for its connection.
    -- Finally, the WebSocket object uses the Rest object for its connection.  
    -- 
    -- Hopefully the flexibility of this architecture is easy to see.  All of the HTTP functionality of the Rest object,
    -- such as HTTP authentication, custom headers, etc. is available to the WebSocket.  Likewise, all of the advanced functionality
    -- of the Socket object is in turn available to the Rest object.  

    -- The high-level steps for accomplishing the task of running the WebSocket protocol through an SSH accomplished as follows:
    -- 1) Create the SSH tunnel using Chilkat Socket.
    -- 2) Open a port-forwarding channel (to the WebSocket server) within the tunnel.
    -- 2) Tell Rest to use the Socket object.
    -- 3) Tell WebSocket to use the Rest object.

    DECLARE @tunnel int
    -- Use "Chilkat_9_5_0.Socket" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Socket', @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:
    DECLARE @success int
    EXEC sp_OAMethod @tunnel, 'SshOpenTunnel', @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, 'SshAuthenticatePw', @success OUT, 'mySshLogin', 'mySshPassword'
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @tunnel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        RETURN
      END

    --  OK, the SSH tunnel is setup.  Now open a channel within the tunnel.
    DECLARE @channel int

    DECLARE @bTls int
    SELECT @bTls = 1
    DECLARE @port int
    SELECT @port = 443
    DECLARE @maxWaitMs int
    SELECT @maxWaitMs = 5000

    -- This returns a socket object that is a single channel within the SSH tunnel.
    -- The SSH channel is our logical port-forwarded connection through the SSH tunnel.
    -- Note: This example establishes a TLS connection to the target WebSocket server.
    -- (The TLS protocol will run on the logical channel within the SSH tunnel.)
    -- Your application can just as easily make a non-TLS connection by changing the arguments
    -- passed to SshOpenChannel.
    EXEC sp_OAMethod @tunnel, 'SshOpenChannel', @channel OUT, 'some-websocket-server.com', @port, @bTls, @maxWaitMs
    EXEC sp_OAGetProperty @tunnel, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN
        EXEC sp_OAGetProperty @tunnel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        RETURN
      END

    -- Create a REST object and tell it to use the SSH channel.
    -- This connection is a TLS running on an SSH channel through an SSH tunnel.
    -- In other words, TLS is wrapped within the SSH tunnel.
    DECLARE @rest int
    -- Use "Chilkat_9_5_0.Rest" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Rest', @rest OUT

    EXEC sp_OAMethod @rest, 'UseConnection', @success OUT, @channel, 0
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @rest, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @channel

        EXEC @hr = sp_OADestroy @tunnel
        EXEC @hr = sp_OADestroy @rest
        RETURN
      END

    -- Finally, tell our WebSocket object to use the Rest object..
    DECLARE @ws int
    -- Use "Chilkat_9_5_0.WebSocket" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.WebSocket', @ws OUT

    -- Tell the WebSocket to use this connection.
    EXEC sp_OAMethod @ws, 'UseConnection', @success OUT, @rest
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @ws, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        EXEC @hr = sp_OADestroy @rest
        EXEC @hr = sp_OADestroy @ws
        RETURN
      END

    -- Add the standard WebSocket open handshake headers that will be needed.
    -- (This adds the required HTTP request headers to the rest object.)
    EXEC sp_OAMethod @ws, 'AddClientHeaders', @success OUT

    -- Add any additional headers that might be desired.
    -- Two common WebSocketSpecific headers are "Sec-WebSocket-Protocol" and "Origin".
    EXEC sp_OAMethod @rest, 'AddHeader', @success OUT, 'Sec-WebSocket-Protocol', 'x-some-websocket-subprotocol'
    EXEC sp_OAMethod @rest, 'AddHeader', @success OUT, 'Origin', 'http://some-websocket-server.com'

    -- Do the open handshake.
    DECLARE @responseBody nvarchar(4000)
    EXEC sp_OAMethod @rest, 'FullRequestNoBody', @responseBody OUT, 'GET', '/something'
    EXEC sp_OAGetProperty @rest, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN
        EXEC sp_OAGetProperty @rest, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        EXEC @hr = sp_OADestroy @rest
        EXEC @hr = sp_OADestroy @ws
        RETURN
      END

    -- If successful, the HTTP response status code should be 101,
    -- and the response body will be empty. (If it failed, we'll have a look
    -- at the response body..)
    DECLARE @statusCode int
    EXEC sp_OAGetProperty @rest, 'ResponseStatusCode', @statusCode OUT

    PRINT 'Response status code: ' + @statusCode

    IF @statusCode <> 101
      BEGIN

        PRINT @responseBody

        PRINT '-- Failed because of unexpected response status code.'
        EXEC @hr = sp_OADestroy @tunnel
        EXEC @hr = sp_OADestroy @rest
        EXEC @hr = sp_OADestroy @ws
        RETURN
      END

    -- We have the expected 101 response, so let's now validate the 
    -- contents of the response, such as the value sent by the server in the
    -- Sec-WebSocket-Accept header. 
    EXEC sp_OAMethod @ws, 'ValidateServerHandshake', @success OUT
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @ws, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        EXEC @hr = sp_OADestroy @rest
        EXEC @hr = sp_OADestroy @ws
        RETURN
      END


    PRINT 'WebSocket connection successful.'

    -- The application may now begin sending and receiving frames on the WebSocket connection.
    -- (At this point, we're done with the rest object...)

    EXEC @hr = sp_OADestroy @tunnel
    EXEC @hr = sp_OADestroy @rest
    EXEC @hr = sp_OADestroy @ws


END
GO