Herald-server NPM

herald-server

v1 is not backward compatible with v0

Use node.js socket server (udp, tcp, unix) for transport messages (or encrypted messages) through applications.

Install with:

npm install herald-server

Dependencies:

crypt-maker

Documentation by jsDuck. Also in RUS.

Usage

Simple example:

    var HeraldServer = require('herald-server');
    var hs = new HeraldServer({}, 'no');
    hs.on('error', function(){
        console.log('HS error:', error);
    });
    hs.on('listening', function(){
        console.log('HS listening on', hs.address());
    });
    hs.listen(8765);
    process.on('SIGINT', function(){
        hs.close();
    });
    process.on('SIGTERM', function(){
        hs.close();
    });

Changes

Add rpc support.
Ping removed (tcp ans unix socket know about connection close). Udp is not recommended.
Some procedures can be spawned on server easily.
Add JSDuck doc.

Methods

new HeraldSever(options[, algorithm, key])

options is an Object. May be {}. Contains properties:

.logger - Logger object - to log inner events
.whiteList - Array of strings or regexps. Default []
.welcomeMessage - String. Then connection opens - send this to socket. Default 'Welcome to Herald Server.'
.messageMaker - Object. Some module, that make and parse messages. See below. Default crypt-maker

algorithm - If need crypt messages - algorithm for crypt. By default doesn't encrypt. key Encryption key.

If use crypt-maker and if algorithm && algorithm !== 'no' and no key passed to constructor - throws error.

hs.listen()

Arguments passed to method are seems as net.Server.listen method of node.js standard api. Use like:

hs.listen(port[, host][, backlog][, callback])
hs.listen(path[, callback])
hs.listen(handle[, callback])
hs.listen(options[, callback])

Options are:

options {Object} - Required. Supports the following properties:
- port {Number} - Optional.
- host {String} - Optional.
- backlog {Number} - Optional.
- path {String} - Optional.
- exclusive {Boolean} - Optional.
callback {Function} - Optional.

For all info about this see: https://nodejs.org/api/net.html#net_server_listen_port_host_backlog_callback

hs.close(callback)

Stops the server from accepting new connections and keeps existing connections.

hs.unref() Experimental

Calling unref on a server will allow the program to exit if this is the only active server in the event system. If the server is already unrefd calling unref again will have no effect.

hs.ref() Experimental

Opposite of unref, calling ref on a previously unrefd server will not let the program exit if it's the only server left (the default behavior). If the server is refd calling ref again will have no effect.

Events

'listening'

Emitted when the server has been bound after calling hs.listen.

'connection'

{Socket Object} The connection object

Emitted when a new connection is made. socket is an instance of net.Socket. Also where if socket.header with header of auth message.

'close'

Emitted when the server closes. Note that if connections exist, this event is not emitted until all connections are ended.

'error'

{Error Object}

Emitted when an error occurs. The 'close' event will be called directly following this event. See example in discussion of hs.listen.

Message format

Every message should has header and body. If there is no header or body - message will not sent.

Authorize

Be careful by default without any encrypt algorithm any can connect to your server if he know format.

Example of message to authorize (without encrypt):

    '{"rpc":"herald-server","action":"authorize","actionId":7,"name":"156512",
    "uid":"156512_86835","messId":76688,"retry":5,"timeout":15000}\r\n
     {"args":{"wellKnown":"pHrAsE","name":"156512","uid":"156512_86835","rand":459}}\r\n\r\n'

If there is some connection with same uid - will not authorize new connection and close it.

Message header format

Fields:

messId Number - id of message.
name String - connection name. Used for whispering and rpc.
uid String - connection uid. Used for whispering and rpc. Unique for every connect.
retry Number optional - Count of retries of sending this message. If no field - will not retry. Now it is ignored by server. Will work soon.
timeout Number optional - Duration in ms to wait answer from client. If no field - will not retry. Now it is ignored by server. Will work soon.

Event:

whisp String optional - name of connection to send event message.
whispUid String optional - uid of connection to send event message.
event String - event name. If no whisp or whispUid sends to all subscribers.

RPC:

actionId Number - id of action.
action String - name of action.
rpc String optional - name of connection to send rpc message.
rpcUid String optional - uid of connection to send rpc message.
rpcRegExp String|RegExp optional - regexp to find connections by name to send rpc message.

Message body format

Body can by plain string, json, number or something else, except functions.

Message examples

Examples shown without any encryption.

RPC by client name message:

     '{"rpc":"applicationToCall","action":"actionToCall","actionId":numberActionIdFromSender,
     "name":"nameOfSender","uid":"uidOfSender","messId":numberMessageId}\r\n
         {"args":{argsObject}}\r\n\r\n'

RPC by client UID message:

     '{"rpcUid":"applicationToCall","action":"actionToCall","actionId":numberActionIdFromSender,
     "name":"nameOfSender","uid":"uidOfSender","messId":numberMessageId}\r\n
         {"args":{argsObject}}\r\n\r\n'

Whispering message:

    '{"whisp":"nameOfAppToWhisp","event":"someSecretEvent","name":"nameOfSender","uid":"uidOfSender",
    "messId":numberMessageId}\r\n"eventBody"\r\n\r\n'

Event message:

    '{"event":"someEvent","name":"nameOfSender","uid":"uidOfSender","messId":numberMessageId}\r\n"eventBody"\r\n\r\n'

LICENSE - "MIT License"

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.