Zig Requires Chilkat v11.0.0+

WebSocket through SSH Tunnel

See more WebSocket Examples

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

const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

    // 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.

    const tunnel = try chilkat.Socket.init();
    defer tunnel.deinit();

    const ssh_hostname = "sftp.example.com";
    const ssh_port = 22;

    // Connect to an SSH server and establish the SSH tunnel:
    tunnel.sshOpenTunnel(ssh_hostname, ssh_port) catch {
        std.debug.print("{s}\n", .{try tunnel.getLastErrorText(alloc)});
        return;
    };

    // Authenticate with the SSH server via a login/password
    // or with a public key.
    // This example demonstrates SSH password authentication.
    tunnel.sshAuthenticatePw("mySshLogin", "mySshPassword") catch {
        std.debug.print("{s}\n", .{try tunnel.getLastErrorText(alloc)});
        return;
    };

    //  OK, the SSH tunnel is setup.  Now open a channel within the tunnel.

    const b_tls = true;
    const port = 443;
    const max_wait_ms = 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.
    const channel = try chilkat.Socket.init();
    defer channel.deinit();
    tunnel.sshNewChannel("some-websocket-server.com", port, b_tls, max_wait_ms, channel) catch {
        std.debug.print("{s}\n", .{try tunnel.getLastErrorText(alloc)});
        return;
    };

    // 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.
    const rest = try chilkat.Rest.init();
    defer rest.deinit();
    rest.useConnection(channel, false) catch {
        std.debug.print("{s}\n", .{try rest.getLastErrorText(alloc)});
        return;
    };

    // Finally, tell our WebSocket object to use the Rest object..
    const ws = try chilkat.WebSocket.init();
    defer ws.deinit();

    // Tell the WebSocket to use this connection.
    ws.useConnection(rest) catch {
        std.debug.print("{s}\n", .{try ws.getLastErrorText(alloc)});
        return;
    };

    // Add the standard WebSocket open handshake headers that will be needed.
    // (This adds the required HTTP request headers to the rest object.)
    ws.addClientHeaders() catch {};

    // Add any additional headers that might be desired.
    // Two common WebSocketSpecific headers are "Sec-WebSocket-Protocol" and "Origin".
    rest.addHeader("Sec-WebSocket-Protocol", "x-some-websocket-subprotocol") catch {};
    rest.addHeader("Origin", "http://some-websocket-server.com") catch {};

    // Do the open handshake.
    const response_body = rest.fullRequestNoBody(alloc, "GET", "/something") catch {
        std.debug.print("{s}\n", .{try rest.getLastErrorText(alloc)});
        return;
    };

    // 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..)
    const status_code = rest.getResponseStatusCode();
    std.debug.print("Response status code: {d}\n", .{status_code});

    if (status_code != 101) {
        std.debug.print("{s}\n", .{response_body});
        std.debug.print("-- Failed because of unexpected response status code.\n", .{});
        return;
    }

    // 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.
    ws.validateServerHandshake() catch {
        std.debug.print("{s}\n", .{try ws.getLastErrorText(alloc)});
        return;
    };

    std.debug.print("WebSocket connection successful.\n", .{});

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