TCP Client

TCPClient library for a JavaScript Plugin

Remarks

The example below shows how to build the backend for a simple terminal program.

Example

plugin.Name = "TCPExample";

plugin.OnChangeRequest = onChangeRequest;

plugin.OnConnect = onConnect;

plugin.OnDisconnect = onDisconnect;

plugin.OnPoll = onPoll;

plugin.OnSynchronizeDevices = onSynchronizeDevices;

plugin.PollingInterval = 0;

plugin.DefaultSettings = { "Host": "192.168.1.100", "Port": "23" };

var tcp = new TCPClient();

var tcpDeviceId = "terminal";

function onChangeRequest(device, attribute, value) {

switch (attribute) {

case "TerminalInput":

tcp.send(value);

break;

default:

return;

}

}

function onConnect() {

var host = plugin.Settings["Host"];

var port = plugin.Settings["Port"];

if (host && port) {

tcp.connect(host, parseInt(port));

}

else {

tcp.connect("192.168.1.219", 23);

}

}

function onDisconnect() {

tcp.close();

}

function onPoll() {

while (true) {

//`receive` blocks until a message is received.

//Our message will be a UTF8 encoded string.

//For byte data use this instead.

//var data = tcp.receive({encoding: null});

var data = tcp.receive();

console.log("message received" + data);

var terminalDevice = plugin.Devices[tcpDeviceId];

if (terminalDevice.TerminalOutput != null) {

terminalDevice.TerminalOutput = terminalDevice.TerminalOutput + "\n" + data;

}

else {

terminalDevice.TerminalOutput = data;

}

}

}

function onSynchronizeDevices() {

var terminalDevice = new Device();

terminalDevice.Id = tcpDeviceId;

terminalDevice.DisplayName = "Terminal Device";

terminalDevice.Capabilities = [];

terminalDevice.Attributes = ["TerminalInput", "TerminalOutput"];

plugin.Devices[terminalDevice.Id] = terminalDevice;

}

Methods

connect

Connects the client to the specified port on the specified host.

connect(host, port, [options])

• host : The IP address or host name to which you intend to connect.
• port : The port number to which you intend to connect.
• options
  • timeout : Time, in milliseconds, to wait before timing out. The default is 0 which waits indefinitely.

close

Closes the client connection.

close()

receive

Receives data on the client.

receive([options])

• options
  • encoding : Defaults to UTF8. Set to null if you wish to receive binary byte data .
  • timeout : Time, in milliseconds, to wait before timing out. The default is 0 which waits indefinitely.

Returns either a message string or bytes depending on the supplied encoding option.

send

Sends data from the client.

send(data, [options])

• data : The data to send. Can be either a string or a byte array.
• options
  • encoding : The encoding for string data. The default is UTF8. Ignored if byte data is supplied.
  • timeout : Time, in milliseconds, to wait before timing out. The default is 0 which waits indefinitely.