(Lianja) WebSocket Connect through HTTP Proxy

This example shows how to establish a WebSocket connection through an HTTP proxy server.

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//  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 using HTTP Proxy example.
//  We first use the Chilkat Socket object to establish a connection to the WebSocket server through an HTTP proxy.
//  Next, the Rest object uses the Socket object for its connection.
//  Finally, the WebSocket object uses the Rest object for its connection.
// 

loRest = createobject("CkRest")
loSocket = createobject("CkSocket")

//  Set the HTTP proxy domain or IP address, and port.
loSocket.HttpProxyHostname = "192.168.1.79"
loSocket.HttpProxyPort = 808

//  Provide authentication to the HTTP proxy, if needed.
loSocket.HttpProxyUsername = "HTTP_PROXY_LOGIN"
loSocket.HttpProxyPassword = "HTTP_PROXY_PASSWORD"
loSocket.HttpProxyAuthMethod = "Basic"

//  Indicate that HTTP requests (i.e. the WebSocket opening handshake) will be sent over the socket.
//  This is important for how the HTTP proxy connection is established.
loSocket.HttpProxyForHttp = .T.

//  Connect to the websocket server through the HTTP proxy.
llBTls = .F.
lnPort = 80
lnMaxWaitMs = 5000
llSuccess = loSocket.Connect("some-websocket-server.com",lnPort,llBTls,lnMaxWaitMs)
if (llSuccess <> .T.) then
    ? "Connect Failure Error Code: " + str(loSocket.ConnectFailReason)
    ? loSocket.LastErrorText
    release loRest
    release loSocket
    return
endif

//  Tell the Rest object to use the connected socket.
llSuccess = loRest.UseConnection(loSocket,.T.)
if (llSuccess <> .T.) then
    ? loRest.LastErrorText
    release loRest
    release loSocket
    return
endif

loWs = createobject("CkWebSocket")

//  Tell the WebSocket to use this connection.
llSuccess = loWs.UseConnection(loRest)
if (llSuccess <> .T.) then
    ? loWs.LastErrorText
    release loRest
    release loSocket
    release loWs
    return
endif

//  Add the standard WebSocket open handshake headers that will be needed.
//  (This adds the required HTTP request headers to the rest object.)
loWs.AddClientHeaders()

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

//  Do the open handshake.
lcResponseBody = loRest.FullRequestNoBody("GET","/something")
if (loRest.LastMethodSuccess <> .T.) then
    ? loRest.LastErrorText
    release loRest
    release loSocket
    release loWs
    return
endif

//  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..)
lnStatusCode = loRest.ResponseStatusCode
? "Response status code: " + str(lnStatusCode)

if (lnStatusCode <> 101) then
    ? lcResponseBody
    ? "-- Failed because of unexpected response status code."
    release loRest
    release loSocket
    release loWs
    return
endif

//  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.
llSuccess = loWs.ValidateServerHandshake()
if (llSuccess <> .T.) then
    ? loWs.LastErrorText
    release loRest
    release loSocket
    release loWs
    return
endif

? "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 and socket objects...)

? "Success."


release loRest
release loSocket
release loWs