+ First, the callbacks are defined in a table. The OnConnected() callback takes care of sending the http + request once the socket is connected. The OnReceivedData() callback sends all data to the console. The + OnError() callback logs any errors. Then, the connection is initiated using the cNetwork::Connect() API + function.
++
+-- Define the callbacks to use for the client connection:
+local ConnectCallbacks =
+{
+ OnConnected = function (a_Link)
+ -- Connection succeeded, send the http request:
+ a_Link:Send("GET / HTTP/1.0\r\nHost: www.google.com\r\n\r\n")
+ end,
+
+ OnError = function (a_Link, a_ErrorCode, a_ErrorMsg)
+ -- Log the error to console:
+ LOG("An error has occurred while talking to google.com: " .. a_ErrorCode .. " (" .. a_ErrorMsg .. ")")
+ end,
+
+ OnReceivedData = function (a_Link, a_Data)
+ -- Log the received data to console:
+ LOG("Incoming http data:\r\n" .. a_Data)
+ end,
+
+ OnRemoteClosed = function (a_Link)
+ -- Log the event into the console:
+ LOG("Connection to www.google.com closed")
+ end,
+}
+
+-- Connect:
+if not(cNetwork:Connect("www.google.com", 80, ConnectCallbacks)) then
+ -- Highly unlikely, but better check for errors
+ LOG("Cannot queue connection to www.google.com")
+end
+-- Note that the connection is being made on the background,
+-- there's no guarantee that it's already connected at this point in code
+
+ ]],
+ },
+
+ {
+ Header = "Example server implementation",
+ Contents =
+ [[
+ The following example, adapted from the NetworkTest plugin, shows a simple example of creating a
+ server listening on a TCP port using the cNetwork API. The server listens on port 9876 and for
+ each incoming connection it sends a welcome message and then echoes back whatever the client has
+ sent ("echo server").
+ + First, the callbacks for the listening server are defined. The most important of those is the + OnIncomingConnection() callback that must return the LinkCallbacks that will be used for the new + connection. In our simple scenario each connection uses the same callbacks, so a predefined + callbacks table is returned; it is, however, possible to define different callbacks for each + connection. This allows the callbacks to be "personalised", for example by the remote IP or the + time of connection. The OnAccepted() and OnError() callbacks only log that they occurred, there's + no processing needed for them.
++ Finally, the cNetwork:Listen() API function is used to create the listening server. The status of + the server is checked and if it is successfully listening, it is stored in a global variable, so + that Lua doesn't garbage-collect it until we actually want the server closed.
++
+-- Define the callbacks used for the incoming connections:
+local EchoLinkCallbacks =
+{
+ OnConnected = function (a_Link)
+ -- This will not be called for a server connection, ever
+ assert(false, "Unexpected Connect callback call")
+ end,
+
+ OnError = function (a_Link, a_ErrorCode, a_ErrorMsg)
+ -- Log the error to console:
+ local RemoteName = "'" .. a_Link:GetRemoteIP() .. ":" .. a_Link:GetRemotePort() .. "'"
+ LOG("An error has occurred while talking to " .. RemoteName .. ": " .. a_ErrorCode .. " (" .. a_ErrorMsg .. ")")
+ end,
+
+ OnReceivedData = function (a_Link, a_Data)
+ -- Send the received data back to the remote peer
+ a_Link:Send(Data)
+ end,
+
+ OnRemoteClosed = function (a_Link)
+ -- Log the event into the console:
+ local RemoteName = "'" .. a_Link:GetRemoteIP() .. ":" .. a_Link:GetRemotePort() .. "'"
+ LOG("Connection to '" .. RemoteName .. "' closed")
+ end,
+}
+
+-- Define the callbacks used by the server:
+local ListenCallbacks =
+{
+ OnAccepted = function (a_Link)
+ -- No processing needed, just log that this happened:
+ LOG("OnAccepted callback called")
+ end,
+
+ OnError = function (a_ErrorCode, a_ErrorMsg)
+ -- An error has occured while listening for incoming connections, log it:
+ LOG("Cannot listen, error " .. a_ErrorCode .. " (" .. a_ErrorMsg .. ")"
+ end,
+
+ OnIncomingConnection = function (a_RemoteIP, a_RemotePort, a_LocalPort)
+ -- A new connection is being accepted, give it the EchoCallbacks
+ return EchoLinkCallbacks
+ end,
+}
+
+-- Start the server:
+local Server = cNetwork:Listen(9876, ListenCallbacks)
+if not(Server:IsListening()) then
+ -- The error has been already printed in the OnError() callbacks
+ -- Just bail out
+ return;
+end
+
+-- Store the server globally, so that it stays open:
+g_Server = Server
+
+...
+
+-- Elsewhere in the code, when terminating:
+-- Close the server and let it be garbage-collected:
+g_Server:Close()
+g_Server = nil
+
+ ]],
+ },
}, -- AdditionalInfo
Functions =