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(Delphi DLL) WebSocket through SSH TunnelThis example shows how to establish a WebSocket connection through an SSH tunnel. The WebSocket protocol communications will be encapsulated within an SSH tunnel. Note: This example requires Chilkat v11.0.0 or greater.
uses Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Rest, WebSocket, Socket; ... procedure TForm1.Button1Click(Sender: TObject); var success: Boolean; tunnel: HCkSocket; sshHostname: PWideChar; sshPort: Integer; bTls: Boolean; port: Integer; maxWaitMs: Integer; channel: HCkSocket; rest: HCkRest; ws: HCkWebSocket; responseBody: PWideChar; statusCode: Integer; begin success := False; // 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. tunnel := CkSocket_Create(); sshHostname := 'sftp.example.com'; sshPort := 22; // Connect to an SSH server and establish the SSH tunnel: success := CkSocket_SshOpenTunnel(tunnel,sshHostname,sshPort); if (success = False) then begin Memo1.Lines.Add(CkSocket__lastErrorText(tunnel)); Exit; end; // Authenticate with the SSH server via a login/password // or with a public key. // This example demonstrates SSH password authentication. success := CkSocket_SshAuthenticatePw(tunnel,'mySshLogin','mySshPassword'); if (success = False) then begin Memo1.Lines.Add(CkSocket__lastErrorText(tunnel)); Exit; end; // OK, the SSH tunnel is setup. Now open a channel within the tunnel. bTls := True; port := 443; 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 SshNewChannel. channel := CkSocket_Create(); success := CkSocket_SshNewChannel(tunnel,'some-websocket-server.com',port,bTls,maxWaitMs,channel); if (success = False) then begin Memo1.Lines.Add(CkSocket__lastErrorText(tunnel)); Exit; 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. rest := CkRest_Create(); success := CkRest_UseConnection(rest,channel,False); if (success = False) then begin Memo1.Lines.Add(CkRest__lastErrorText(rest)); Exit; end; // Finally, tell our WebSocket object to use the Rest object.. ws := CkWebSocket_Create(); // Tell the WebSocket to use this connection. success := CkWebSocket_UseConnection(ws,rest); if (success = False) then begin Memo1.Lines.Add(CkWebSocket__lastErrorText(ws)); Exit; end; // Add the standard WebSocket open handshake headers that will be needed. // (This adds the required HTTP request headers to the rest object.) CkWebSocket_AddClientHeaders(ws); // Add any additional headers that might be desired. // Two common WebSocketSpecific headers are "Sec-WebSocket-Protocol" and "Origin". CkRest_AddHeader(rest,'Sec-WebSocket-Protocol','x-some-websocket-subprotocol'); CkRest_AddHeader(rest,'Origin','http://some-websocket-server.com'); // Do the open handshake. responseBody := CkRest__fullRequestNoBody(rest,'GET','/something'); if (CkRest_getLastMethodSuccess(rest) = False) then begin Memo1.Lines.Add(CkRest__lastErrorText(rest)); Exit; 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..) statusCode := CkRest_getResponseStatusCode(rest); Memo1.Lines.Add('Response status code: ' + IntToStr(statusCode)); if (statusCode <> 101) then begin Memo1.Lines.Add(responseBody); Memo1.Lines.Add('-- Failed because of unexpected response status code.'); Exit; 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. success := CkWebSocket_ValidateServerHandshake(ws); if (success = False) then begin Memo1.Lines.Add(CkWebSocket__lastErrorText(ws)); Exit; end; Memo1.Lines.Add('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...) CkSocket_Dispose(tunnel); CkSocket_Dispose(channel); CkRest_Dispose(rest); CkWebSocket_Dispose(ws); end; |
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