Xbase++

WebSocket Connect through HTTP Proxy

See more WebSocket Examples

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

LOCAL nSuccess
LOCAL oRest
LOCAL oSocket
LOCAL nBTls
LOCAL nPort
LOCAL nMaxWaitMs
LOCAL oWs
LOCAL cResponseBody
LOCAL nStatusCode

nSuccess := 0

//  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.  
//  

oRest := CreateObject("Chilkat.Rest")
oSocket := CreateObject("Chilkat.Socket")

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

//  Provide authentication to the HTTP proxy, if needed.
oSocket:HttpProxyUsername := "HTTP_PROXY_LOGIN"
oSocket:HttpProxyPassword := "HTTP_PROXY_PASSWORD"
oSocket: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.
oSocket:HttpProxyForHttp := 1

//  Connect to the websocket server through the HTTP proxy.
nBTls := 0
nPort := 80
nMaxWaitMs := 5000
nSuccess := oSocket:Connect("some-websocket-server.com", nPort, nBTls, nMaxWaitMs)
IF (nSuccess != 1)
    ? "Connect Failure Error Code: " + Str(oSocket:ConnectFailReason)
    ? oSocket:LastErrorText
    oRest:destroy()
    oSocket:destroy()
    RETURN
ENDIF

//  Tell the Rest object to use the connected socket.
nSuccess := oRest:UseConnection(oSocket, 1)
IF (nSuccess != 1)
    ? oRest:LastErrorText
    oRest:destroy()
    oSocket:destroy()
    RETURN
ENDIF

oWs := CreateObject("Chilkat.WebSocket")

//  Tell the WebSocket to use this connection.
nSuccess := oWs:UseConnection(oRest)
IF (nSuccess != 1)
    ? oWs:LastErrorText
    oRest:destroy()
    oSocket:destroy()
    oWs:destroy()
    RETURN
ENDIF

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

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

//  Do the open handshake.
cResponseBody := oRest:FullRequestNoBody("GET", "/something")
IF (oRest:LastMethodSuccess != 1)
    ? oRest:LastErrorText
    oRest:destroy()
    oSocket:destroy()
    oWs:destroy()
    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..)
nStatusCode := oRest:ResponseStatusCode
? "Response status code: " + Str(nStatusCode)

IF (nStatusCode != 101)
    ? cResponseBody
    ? "-- Failed because of unexpected response status code."
    oRest:destroy()
    oSocket:destroy()
    oWs:destroy()
    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. 
nSuccess := oWs:ValidateServerHandshake()
IF (nSuccess != 1)
    ? oWs:LastErrorText
    oRest:destroy()
    oSocket:destroy()
    oWs:destroy()
    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."

oRest:destroy()
oSocket:destroy()
oWs:destroy()