#node-ipc a nodejs module for local and remote Inter Process Communication

npm install node-ipc

this is a new project so more documentation will come

---

Types of IPC Sockets

1. Local IPC Uses Unix Sockets to give lightning fast communication and avoid the network card to reduce overhead and latency. Local Unix Socket examples
2. IPC over TCP Uses TCP Sockets to give the most reliable communication across the network. Can be used for local IPC as well, but is slower than #1's Unix Socket Implementation because TCP sockets go through the network card while Unix Sockets do not. Local or remote network TCP Socket examples
3. Remote IPC over TLS coming soon...
4. Remote IPC over UDP Uses UDP Sockets to give the fastest network communication. UDP is less reliable but much faster than TCP. It is best used for streaming non critical data like sound, video, or multiplayer game data as it can drop packets depending on network connectivity and other factors. UDP can be used for local IPC as well, but is slower than #1's Unix Socket Implementation because UDP sockets go through the network card while Unix Sockets do not. Local or remote network UDP Socket examples

---

IPC Default Variables

ipc.config
Set these variables in the ipc.config scope to overwrite or set default values.

{
    appspace        : 'app.',
    socketRoot      : '/tmp/',
    id              : os.hostname(),
    networkHost     : 'localhost',
    networkPort     : 8000,
    encoding        : 'utf8',
    silent          : false,
    maxConnections  : 100,
    retry           : 500
}

• appspace used for Unix Socket (Unix Domain Socket) namespacing. If not set specifically, the Unix Domain Socket will combine the socketRoot, appspace, and id to form the Unix Socket Path for creation or binding. This is available incase you have many apps running on your system, you may have several sockets with the same id, but if you change the appspace, you will still have app specic unique sockets.
• socketRoot the directory in which to create or bind to a Unix Socket
• id the id of this socket or service
• networkHost the local or remote host on which TCP, TLS or UDP Sockets should connect
• networkPort the default port on which TCP, TLS, or UDP sockets should connect
• encoding the default encoding for data sent on sockets
• silent turn on/off logging default is false which means logging is on
• maxConnections this is the max number of connections allowed to a socket. It is currently only being set on Unix Sockets. Other Socket types are using the system defaults.
• retry this is the time in milliseconds a client will wait before trying to reconnect to a server if the connection is lost. This does not effect UDP sockets since they do not have a client server relationship like Unix Sockets and TCP Sockets.

---

IPC Methods

These methods are available in the IPC Scope.

log

ipc.log(a,b,c,d,e...);
ipc.log will accept any number of arguments and if ipc.config.silent is not set, it will concat them all with a sincle space ' ' between them and then log them to the console. This is fast because it prevents any concation from happening if the ipc is set to silent. That way if you leave your logging in place it should not effect performance.

the log also supports colors implementation. All of the available styles are supported and the theme styles are as follows :

{
    good    : 'green',
    notice  : 'yellow',
    warn    : 'red',
    error   : 'redBG',
    debug   : 'magenta',
    variable: 'cyan',
    data    : 'blue'
}    

You can override any of these settings by requireing colors and setting the theme as follows :

var colors=require('colors');

colors.setTheme(
    {
        good    : 'zebra',
        notice  : 'redBG',
        ...
    }    
);

connectTo

Used for connecting as a client to local Unix Sockets. This is the fastst way for processes on the same machine to communicate because it bypasses the network card which TCP and UDP must both use. ipc.connectTo(id,path,callback);

1. id required is the string id of the socket being connected to. The socket with this id is added to the ipc.of object when created.
2. path optional is the path of the Unix Domain Socket File, if not set this will be defaylted to ipc.config.socketRoot+ipc.config.appspace+id
3. callback optional this is the function to execute when the socket has been created.

examples

ipc.connectTo('world');

or using just an id and a callback

ipc.connectTo(
    'world',
    function(){
        ipc.of.world.on(
            'hello',
            function(data){
                ipc.log(data.debug); 
                //if data was a string, it would have the color set to the debug style applied to it
            }
        )
    }
);

or explicitly setting the path

ipc.connectTo(
    'world',
    'myapp.world'
);

or explicitly setting the path with callback

ipc.connectTo(
    'world',
    'myapp.world',
    function(){
        ...
    }
);

connectToNet

Used to connect as a client to a TCP or TLS socket via the network card. This can be local or remote, if local, it is recommended that you use the Unix Socket Implementaion of connectTo instead as it is much faster since it avoids the network card alltogether. ipc.connectToNet(id,host,port,callback)

1. id required is the string id of the socket being connected to. For TCP & TLS sockets, this id is added to the ipc.of object when the socket is created with a refrence to the socket.
2. host optional is the host on which the TCP or TLS socket resides. This will default to ipc.config.networkHost if not specified.
3. port optional
4. callback optional this is the function to execute when the socket has been created.

examples arguments can be ommitted solong as they are still in order.
So while the default is : (id,host,port,callback), the following examples will still work because they are still in order (id,port,callback) or (id,host,callback) or (id,port) etc.

ipc.connectToNet('world');

or using just an id and a callback

ipc.connectToNet(
    'world',
    function(){
        ...
    }
);

or explicitly setting the host and path

ipc.connectToNet(
    'world',
    'myapp.com',
    3435
);

or only explicitly setting port and callback

ipc.connectToNet(
    'world',
    3435,
    function(){
        ...
    }
);

serve

coming soon ...

serveNet

coming soon ... For TCP, TLS & UDP servers this is most likely going to be local host or 0.0.0.0 unless you have something like node-http-server installed to run subdomains for you.

---

Basic Examples

Server for Unix Sockets & TCP Sockets

The server is the process keeping a socket for IPC open. Multiple sockets can connect to this server and talk to it. It can also broadcast to all clients or emit to a specific client. This is the most basic example which will work for both local Unix Sockets and local or remote network TCP Sockets.

var ipc=require('node-ipc');

ipc.config.id   = 'world';
ipc.config.retry= 1500;

ipc.serve(
    function(){
        ipc.server.on(
            'message',
            function(data,socket){
                ipc.log('got a message : '.debug, data);
                socket.emit(
                    'message',
                    data+' world!'
                );
            }
        );
    }
);

ipc.server.start();

Client for Unix Sockets & TCP Sockets

The client connects to the servers socket for Inter Process Communication. The socket will recieve events emitted to it specifically as well as events which are broadcast out on the socket by the server. This is the most basic example which will work for both local Unix Sockets and local or remote network TCP Sockets.

var ipc=require('../../../node-ipc');

ipc.config.id   = 'hello';
ipc.config.retry= 1500;

ipc.connectTo(
    'world',
    function(){
        ipc.of.world.on(
            'connect',
            function(){
                ipc.log('## connected to world ##'.rainbow, ipc.config.delay);
                ipc.of.world.emit(
                    'message',
                    'hello'
                )
            }
        );
        ipc.of.world.on(
            'disconnect',
            function(){
                ipc.log('disconnected from world'.notice);
            }
        );
        ipc.of.world.on(
            'message',
            function(data){
                ipc.log('got a message from world : '.debug, data);
            }
        );
    }
);

Server & Client for UDP Sockets

UDP Sockets are different than Unix & TCP Sockets because they must be bound to a unique port on their machine to recieve messages. For example, A TCP or Unix Socket client could just connect to a seperate TCP or Unix Socket sever. That client could then exchange, both send and recive, data on the servers port or location. UDP Sockets can not do this. They must bind to a port to recieve or send data.

This means a UDP Client and Server are the same thing because inorder to recieve data, a UDP Socket must have its own port to recieve data on, and only one process can use this port at a time. It also means that inorder to emit or broadcast data the UDP server will need to know the host and port of the Socket it intends to broadcast the data to.

This is the most basic example which will work for both local Unix Sockets and local or remote network TCP Sockets.

UDP Server 1 - "World"

var ipc=require('../../../node-ipc');

ipc.config.id   = 'world';
ipc.config.retry= 1500;

ipc.serveNet(
    'udp4',
    function(){
        console.log(123);
        ipc.server.on(
            'message',
            function(data,socket){
                ipc.log('got a message from '.debug, data.from.variable ,' : '.debug, data.message.variable);
                ipc.server.emit(
                    socket,
                    'message',
                    {
                        from    : ipc.config.id,
                        message : data.message+' world!'
                    }
                );
            }
        );
        
        console.log(ipc.server);
    }
);

ipc.server.define.listen.message='This event type listens for message strings as value of data key.';

ipc.server.start();

UDP Server 2 - "Hello"

note we set the port here to 8001 because the world server is already using the default ipc.config.networkPort of 8000. So we can not bind to 8000 while world is using it.

ipc.config.id   = 'hello';
ipc.config.retry= 1500;

ipc.serveNet(
    8001,
    'udp4',
    function(){
        ipc.server.on(
            'message',
            function(data){
                ipc.log('got Data');
                ipc.log('got a message from '.debug, data.from.variable ,' : '.debug, data.message.variable);
            }
        );
        ipc.server.emit(
            {
                address : 'localhost',
                port    : ipc.config.networkPort
            },
            'message',
            {
                from    : ipc.config.id,
                message : 'Hello'
            }
        );
    }
);

ipc.server.define.listen.message='This event type listens for message strings as value of data key.';

ipc.server.start();