node-ipc

a nodejs module for local and remote Inter Process Communication with full support for Linux, Mac and Windows. It also supports all forms of socket communication from low level unix and windows sockets to UDP and secure TLS and TCP sockets.

A great solution for complex multiprocess Neural Networking in Node.JS

npm install node-ipc

for node <v14

npm install node-ipc@^9.0.0

NPM Stats

npm info : See npm trends and stats for node-ipc

GitHub info :

Code Coverage Info :

Run npm run coverage to host a local version of the coverage report on localhost:8080 This is the same format as Istanbul and NYC. It should be very familiar.

Testing done with vanilla-test
vanilla-test integrates with c8 for native ESM coverage without the need to transpile your code. At the time of writing, this is the only way to natively test ESM, and it is amazing!

Package details websites :

• GitHub.io site. A prettier version of this site.
• NPM Module. The npm page for the node-ipc module.

This work is licenced via the MIT Licence.

Older versions of node

the latest versions of node-ipc may work with the --harmony flag. Officially though, we support node v4 and newer with es5 and es6

Testing

npm test will run the jasmine tests with istanbul for node-ipc and generate a coverage report in the spec folder.

You may want to install jasmine and istanbul globally with sudo npm install -g jasmine istanbul

---

Contents

1. Types of IPC Sockets and Supporting OS
2. IPC Config
3. IPC Methods
   1. log
   2. connectTo
   3. connectToNet
   4. disconnect
   5. serve
   6. serveNet
4. IPC Stores and Default Variables
5. IPC Events
6. Multiple IPC instances
7. Basic Examples
   1. Server for Unix||Windows Sockets & TCP Sockets
   2. Client for Unix||Windows Sockets & TCP Sockets
   3. Server & Client for UDP Sockets
   4. Raw Buffers, Real Time and / or Binary Sockets
8. Working with TLS/SSL Socket Servers & Clients
9. Node Code Examples

---

Types of IPC Sockets

Type	Stability	Definition
Unix Socket or Windows Socket	Stable	Gives Linux, Mac, and Windows lightning fast communication and avoids the network card to reduce overhead and latency. Local Unix and Windows Socket examples
TCP Socket	Stable	Gives 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 and Windows Sockets do not. Local or remote network TCP Socket examples
TLS Socket	Stable	Configurable and secure network socket over SSL. Equivalent to https. TLS/SSL documentation
UDP Sockets	Stable	Gives 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 or Windows Socket Implementation because UDP sockets go through the network card while Unix and Windows Sockets do not. Local or remote network UDP Socket examples

OS	Supported Sockets
Linux	Unix, Posix, TCP, TLS, UDP
Mac	Unix, Posix, TCP, TLS, UDP
Win	Windows, TCP, TLS, UDP

---

IPC Config

ipc.config

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

1
2    {
3        appspace        : 'app.',
4        socketRoot      : '/tmp/',
5        id              : os.hostname(),
6        networkHost     : 'localhost', //should resolve to 127.0.0.1 or ::1 see the table below related to this
7        networkPort     : 8000,
8        readableAll     : false,
9        writableAll     : false,
10        encoding        : 'utf8',
11        rawBuffer       : false,
12        delimiter       : '\f',
13        sync            : false,
14        silent          : false,
15        logInColor      : true,
16        logDepth        : 5,
17        logger          : console.log,
18        maxConnections  : 100,
19        retry           : 500,
20        maxRetries      : false,
21        stopRetrying    : false,
22        unlink          : true,
23        interfaces      : {
24            localAddress: false,
25            localPort   : false,
26            family      : false,
27            hints       : false,
28            lookup      : false
29        }
30    }
31

variable	documentation
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 in case 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
readableAll	makes the pipe readable for all users including windows services
writableAll	makes the pipe writable for all users including windows services
encoding	the default encoding for data sent on sockets. Mostly used if rawBuffer is set to true. Valid values are : ascii utf8 utf16le ucs2 base64 hex .
rawBuffer	if true, data will be sent and received as a raw node Buffer NOT an Object as JSON. This is great for Binary or hex IPC, and communicating with other processes in languages like C and C++
delimiter	the delimiter at the end of each data packet.
sync	synchronous requests. Clients will not send new requests until the server answers.
silent	turn on/off logging default is false which means logging is on
logInColor	turn on/off util.inspect colors for ipc.log
logDepth	set the depth for util.inspect during ipc.log
logger	the function which receives the output from ipc.log; should take a single string argument
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.
maxRetries	if set, it represents the maximum number of retries after each disconnect before giving up and completely killing a specific connection
stopRetrying	Defaults to false meaning clients will continue to retry to connect to servers indefinitely at the retry interval. If set to any number the client will stop retrying when that number is exceeded after each disconnect. If set to true in real time it will immediately stop trying to connect regardless of maxRetries. If set to 0, the client will NOT try to reconnect.
unlink	Defaults to true meaning that the module will take care of deleting the IPC socket prior to startup. If you use node-ipc in a clustered environment where there will be multiple listeners on the same socket, you must set this to false and then take care of deleting the socket in your own code.
interfaces	primarily used when specifying which interface a client should connect through. see the socket.connect documentation in the node.js api

---

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 single space ' ' between them and then log them to the console. This is fast because it prevents any concatenation from happening if the ipc.config.silent is set true. That way if you leave your logging in place it should have almost no effect on performance.

The log also uses util.inspect You can control if it should log in color, the log depth, and the destination via ipc.config

1
2    ipc.config.logInColor=true; //default
3    ipc.config.logDepth=5; //default    
4    ipc.config.logger=console.log.bind(console); // default
5

---

connectTo

ipc.connectTo(id,path,callback);

Used for connecting as a client to local Unix Sockets and Windows Sockets. This is the fastest way for processes on the same machine to communicate because it bypasses the network card which TCP and UDP must both use.

variable	required	definition
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.
path	optional	is the path of the Unix Domain Socket File, if the System is Windows, this will automatically be converted to an appropriate pipe with the same information as the Unix Domain Socket File. If not set this will default to ipc.config.socketRoot+ipc.config.appspace+id
callback	optional	this is the function to execute when the socket has been created.

examples arguments can be ommitted so long as they are still in order.

1
2    ipc.connectTo('world');
3

or using just an id and a callback

1
2    ipc.connectTo(
3        'world',
4        function(){
5            ipc.of.world.on(
6                'hello',
7                function(data){
8                    ipc.log(data.debug);
9                    //if data was a string, it would have the color set to the debug style applied to it
10                }
11            )
12        }
13    );
14

or explicitly setting the path

1
2    ipc.connectTo(
3        'world',
4        'myapp.world'
5    );
6

or explicitly setting the path with callback

1
2    ipc.connectTo(
3        'world',
4        'myapp.world',
5        function(){
6            ...
7        }
8    );
9

---

connectToNet

ipc.connectToNet(id,host,port,callback)

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 and Windows Socket Implementaion of connectTo instead as it is much faster since it avoids the network card altogether.

For TLS and SSL Sockets see the node-ipc TLS and SSL docs. They have a few additional requirements, and things to know about and so have their own doc.

variable	required	definition
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 reference to the socket.
host	optional	is the host on which the TCP or TLS socket resides. This will default to ipc.config.networkHost if not specified.
port	optional	the port on which the TCP or TLS socket resides.
callback	optional	this is the function to execute when the socket has been created.

examples arguments can be ommitted so long 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.

1
2    ipc.connectToNet('world');
3

or using just an id and a callback

1
2    ipc.connectToNet(
3        'world',
4        function(){
5            ...
6        }
7    );
8

or explicitly setting the host and path

1
2    ipc.connectToNet(
3        'world',
4        'myapp.com',serve(path,callback)
5        3435
6    );
7

or only explicitly setting port and callback

1
2    ipc.connectToNet(
3        'world',
4        3435,
5        function(){
6            ...
7        }
8    );
9

---

disconnect

ipc.disconnect(id)

Used to disconnect a client from a Unix, Windows, TCP or TLS socket. The socket and its refrence will be removed from memory and the ipc.of scope. This can be local or remote. UDP clients do not maintain connections and so there are no Clients and this method has no value to them.

variable	required	definition
id	required	is the string id of the socket from which to disconnect.

examples

1
2    ipc.disconnect('world');
3

---

serve

ipc.serve(path,callback);

Used to create local Unix Socket Server or Windows Socket Server to which Clients can bind. The server can emit events to specific Client Sockets, or broadcast events to all known Client Sockets.

variable	required	definition
path	optional	This is the path of the Unix Domain Socket File, if the System is Windows, this will automatically be converted to an appropriate pipe with the same information as the Unix Domain Socket File. If not set this will default to ipc.config.socketRoot+ipc.config.appspace+id
callback	optional	This is a function to be called after the Server has started. This can also be done by binding an event to the start event like ipc.server.on('start',function(){});

examples arguments can be omitted so long as they are still in order.

1
2    ipc.serve();
3

or specifying callback

1
2    ipc.serve(
3        function(){...}
4    );
5

or specify path

1
2    ipc.serve(
3        '/tmp/myapp.myservice'
4    );
5

or specifying everything

1
2    ipc.serve(
3        '/tmp/myapp.myservice',
4        function(){...}
5    );
6

---

serveNet

serveNet(host,port,UDPType,callback)

Used to create TCP, TLS or UDP Socket Server to which Clients can bind or other servers can send data to. The server can emit events to specific Client Sockets, or broadcast events to all known Client Sockets.

variable	required	definition
host	optional	If not specified this defaults to the first address in os.networkInterfaces(). For TCP, TLS & UDP servers this is most likely going to be 127.0.0.1 or ::1
port	optional	The port on which the TCP, UDP, or TLS Socket server will be bound, this defaults to 8000 if not specified
UDPType	optional	If set this will create the server as a UDP socket. 'udp4' or 'udp6' are valid values. This defaults to not being set. When using udp6 make sure to specify a valid IPv6 host, like ::1
callback	optional	Function to be called when the server is created

examples arguments can be ommitted solong as they are still in order.

default tcp server

1
2    ipc.serveNet();
3

default udp server

1
2    ipc.serveNet('udp4');
3

or specifying TCP server with callback

1
2    ipc.serveNet(
3        function(){...}
4    );
5

or specifying UDP server with callback

1
2    ipc.serveNet(
3        'udp4',
4        function(){...}
5    );
6

or specify port

1
2    ipc.serveNet(
3        3435
4    );
5

or specifying everything TCP

1
2    ipc.serveNet(
3        'MyMostAwesomeApp.com',
4        3435,
5        function(){...}
6    );
7

or specifying everything UDP

1
2    ipc.serveNet(
3        'MyMostAwesomeApp.com',
4        3435,
5        'udp4',
6        function(){...}
7    );
8

---

IPC Stores and Default Variables

variable	definition
ipc.of	This is where socket connection refrences will be stored when connecting to them as a client via the ipc.connectTo or iupc.connectToNet. They will be stored based on the ID used to create them, eg : ipc.of.mySocket
ipc.server	This is a refrence to the server created by ipc.serve or ipc.serveNet

---

IPC Server Methods

method	definition
start	start serving need to call serve or serveNet first to set up the server
stop	close the server and stop serving

---

IPC Events

event name	params	definition
error	err obj	triggered when an error has occured
connect		triggered when socket connected
disconnect		triggered by client when socket has disconnected from server
socket.disconnected	socket destroyedSocketID	triggered by server when a client socket has disconnected
destroy		triggered when socket has been totally destroyed, no further auto retries will happen and all references are gone.
data	buffer	triggered when ipc.config.rawBuffer is true and a message is received.
your event type	your event data	triggered when a JSON message is received. The event name will be the type string from your message and the param will be the data object from your message eg : { type:'myEvent',data:{a:1}}

Multiple IPC Instances

Sometimes you might need explicit and independent instances of node-ipc. Just for such scenarios we have exposed the core IPC class on the IPC singleton.

1
2    import {IPCModule} from 'node-ipc';
3
4    const ipc=new RawIPC;
5    const someOtherExplicitIPC=new RawIPC;
6
7
8    //OR
9
10    const ipc=from 'node-ipc');
11    const someOtherExplicitIPC=new ipc.IPC;
12
13
14    //setting explicit configs
15
16    //keep one silent and the other verbose
17    ipc.config.silent=true;
18    someOtherExplicitIPC.config.silent=true;
19
20    //make one a raw binary and the other json based ipc
21    ipc.config.rawBuffer=false;
22
23    someOtherExplicitIPC.config.rawBuffer=true;
24    someOtherExplicitIPC.config.encoding='hex';
25

---

Basic Examples

You can find Advanced Examples in the examples folder. In the examples you will find more complex demos including multi client examples.

Server for Unix Sockets, Windows 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 local Unix and Windows Sockets as well as local or remote network TCP Sockets.

1
2    import ipc from 'node-ipc';
3
4    ipc.config.id   = 'world';
5    ipc.config.retry= 1500;
6
7    ipc.serve(
8        function(){
9            ipc.server.on(
10                'message',
11                function(data,socket){
12                    ipc.log('got a message : '.debug, data);
13                    ipc.server.emit(
14                        socket,
15                        'message',  //this can be anything you want so long as
16                                    //your client knows.
17                        data+' world!'
18                    );
19                }
20            );
21			ipc.server.on(
22				'socket.disconnected',
23				function(socket, destroyedSocketID) {
24					ipc.log('client ' + destroyedSocketID + ' has disconnected!');
25				}
26			);
27        }
28    );
29
30    ipc.server.start();
31

Client for Unix Sockets & TCP Sockets

The client connects to the servers socket for Inter Process Communication. The socket will receive 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.

1
2    import ipc from 'node-ipc';
3
4    ipc.config.id   = 'hello';
5    ipc.config.retry= 1500;
6
7    ipc.connectTo(
8        'world',
9        function(){
10            ipc.of.world.on(
11                'connect',
12                function(){
13                    ipc.log('## connected to world ##'.rainbow, ipc.config.delay);
14                    ipc.of.world.emit(
15                        'message',  //any event or message type your server listens for
16                        'hello'
17                    )
18                }
19            );
20            ipc.of.world.on(
21                'disconnect',
22                function(){
23                    ipc.log('disconnected from world'.notice);
24                }
25            );
26            ipc.of.world.on(
27                'message',  //any event or message type your server listens for
28                function(data){
29                    ipc.log('got a message from world : '.debug, data);
30                }
31            );
32        }
33    );
34

Server & Client for UDP Sockets

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

This means a UDP Client and Server are the same thing because in order to receive data, a UDP Socket must have its own port to receive data on, and only one process can use this port at a time. It also means that in order 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 and remote UDP Sockets.

UDP Server 1 - "World"

1
2    import ipc from 'node-ipc';
3
4    ipc.config.id   = 'world';
5    ipc.config.retry= 1500;
6
7    ipc.serveNet(
8        'udp4',
9        function(){
10            console.log(123);
11            ipc.server.on(
12                'message',
13                function(data,socket){
14                    ipc.log('got a message from '.debug, data.from.variable ,' : '.debug, data.message.variable);
15                    ipc.server.emit(
16                        socket,
17                        'message',
18                        {
19                            from    : ipc.config.id,
20                            message : data.message+' world!'
21                        }
22                    );
23                }
24            );
25
26            console.log(ipc.server);
27        }
28    );
29
30    ipc.server.start();
31

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.

1
2    ipc.config.id   = 'hello';
3    ipc.config.retry= 1500;
4
5    ipc.serveNet(
6        8001,
7        'udp4',
8        function(){
9            ipc.server.on(
10                'message',
11                function(data){
12                    ipc.log('got Data');
13                    ipc.log('got a message from '.debug, data.from.variable ,' : '.debug, data.message.variable);
14                }
15            );
16            ipc.server.emit(
17                {
18                    address : '127.0.0.1', //any hostname will work
19                    port    : ipc.config.networkPort
20                },
21                'message',
22                {
23                    from    : ipc.config.id,
24                    message : 'Hello'
25                }
26            );
27        }
28    );
29
30    ipc.server.start();
31

Raw Buffer or Binary Sockets

Binary or Buffer sockets can be used with any of the above socket types, however the way data events are emit is slightly different. These may come in handy if working with embedded systems or C / C++ processes. You can even make sure to match C or C++ string typing.

When setting up a rawBuffer socket you must specify it as such :

1
2    ipc.config.rawBuffer=true;
3

You can also specify its encoding type. The default is utf8

1
2    ipc.config.encoding='utf8';
3

emit string buffer :

1
2    //server
3    ipc.server.emit(
4        socket,
5        'hello'
6    );
7
8    //client
9    ipc.of.world.emit(
10        'hello'
11    )
12

emit byte array buffer :

1
2    //hex encoding may work best for this.
3    ipc.config.encoding='hex';
4
5    //server
6    ipc.server.emit(
7        socket,
8        [10,20,30]
9    );
10
11    //client
12    ipc.server.emit(
13        [10,20,30]
14    );
15

emit binary or hex array buffer, this is best for real time data transfer, especially whan connecting to C or C++ processes, or embedded systems :

1
2    ipc.config.encoding='hex';
3
4    //server
5    ipc.server.emit(
6        socket,
7        [0x05,0x6d,0x5c]
8    );
9
10    //client
11    ipc.server.emit(
12        [0x05,0x6d,0x5c]
13    );
14

Writing explicit buffers, int types, doubles, floats etc. as well as big endian and little endian data to raw buffer nostly valuable when connecting to C or C++ processes, or embedded systems (see more detailed info on buffers as well as UInt, Int, double etc. here)[https://nodejs.org/api/buffer.html]:

1
2    ipc.config.encoding='hex';
3
4    //make a 6 byte buffer for example
5    const myBuffer=Buffer.alloc(6).fill(0);
6
7    //fill the first 2 bytes with a 16 bit (2 byte) short unsigned int
8
9    //write a UInt16 (2 byte or short) as Big Endian
10    myBuffer.writeUInt16BE(
11        2, //value to write
12        0 //offset in bytes
13    );
14    //OR
15    myBuffer.writeUInt16LE(0x2,0);
16    //OR
17    myBuffer.writeUInt16LE(0x02,0);
18
19    //fill the remaining 4 bytes with a 32 bit (4 byte) long unsigned int
20
21    //write a UInt32 (4 byte or long) as Big Endian
22    myBuffer.writeUInt32BE(
23        16772812, //value to write
24        2 //offset in bytes
25    );
26    //OR
27    myBuffer.writeUInt32BE(0xffeecc,0)
28
29    //server
30    ipc.server.emit(
31        socket,
32        myBuffer
33    );
34
35    //client
36    ipc.server.emit(
37        myBuffer
38    );
39

Server with the cluster Module

node-ipc can be used with Node.js' cluster module to provide the ability to have multiple readers for a single socket. Doing so simply requires you to set the unlink property in the config to false and take care of unlinking the socket path in the master process:

Server

1
2    import fs  from 'fs';
3    import ipc from 'node-ipc';
4    import {cpus}  from 'os';
5    import cluster  from 'cluster';
6    
7    const cpuCount=cpus().length;
8
9    const socketPath='/tmp/ipc.sock';
10
11    ipc.config.unlink = false;
12
13    if (cluster.isMaster) {
14       if (fs.existsSync(socketPath)) {
15           fs.unlinkSync(socketPath);
16       }
17
18       for (let i = 0; i < cpuCount; i++) {
19           cluster.fork();
20       }
21    }else{
22       ipc.serve(
23         socketPath,
24         function() {
25           ipc.server.on(
26             'currentDate',
27             function(data,socket) {
28               console.log(`pid ${process.pid} got: `, data);
29             }
30           );
31         }
32      );
33
34      ipc.server.start();
35      console.log(`pid ${process.pid} listening on ${socketPath}`);
36    }
37

Client

1
2    import fs  from 'fs';
3    import ipc  from 'node-ipc';
4
5    const socketPath = '/tmp/ipc.sock';
6
7    //loop forever so you can see the pid of the cluster sever change in the logs
8    setInterval(
9      function() {
10        ipc.connectTo(
11          'world',
12          socketPath,
13          connecting
14         );
15      },
16      2000
17    );
18
19    function connecting(socket) {
20      ipc.of.world.on(
21        'connect',
22        function() {
23          ipc.of.world.emit(
24            'currentDate',
25            {
26                 message: new Date().toISOString()
27            }
28          );
29          ipc.disconnect('world');
30        }
31      );
32    }
33

Licensed under MIT license

See the MIT license file.