telnet-rxjs-ansgar
v2.4.0
Published
A node.js telnet library that wraps the sockets with RxJS observables
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telnet-rxjs
A node.js telnet library that wraps the sockets with RxJS observables.
SYNPOSIS
Connect to a remote server
import { Telnet } from 'telnet-rxjs';
// const Telnet = require('telnet-rxjs').Telnet;
// const { Telnet } = require('telnet-rxjs');
const client = Telnet.client('www.yahoo.com:80');
let connected = false;
client.filter((event) => event instanceof Telnet.Event.Connected)
.subscribe((event) => {
connected = true;
client.sendln('GET /');
});
client.data
.subscribe((data) => {
if (!connected) {
return;
}
console.log(data);
});
client.connect();
Start a server
import { Telnet } from 'telnet-rxjs';
// const Telnet = require('telnet-rxjs').Telnet;
// const { Telnet } = require('telnet-rxjs');
const server = Telnet.server(80);
server.filter((event) => event instanceof Telnet.Event.Connected)
.subscribe((event) => {
const socket = event.connection.socket;
if (!socket) {
console.error('No socket for', event.connection);
return;
}
console.log('Connection received from', socket.remoteAddress);
event.connection.sendln('Hello!');
event.connection.disconnect();
});
server.start().then(() => {
console.log('Server has been started.');
});
INSTALLATION
npm install telnet-rxjs
Dependencies
DESCRIPTION
telnet-rxjs
is a simple wrapper around a telnet client or server, using RxJS for handling data received from the server.
Telnet Client
Create a Connection
Connections are created by using the Telnet.client
static factory method or createClient
function. This method takes two arguments
- The URI of the host to connect to
- Optionally, additional options to pass to the network socket
The URI should be in formats similar to protocol:host:port
. Host and port are both required. Protocol can be either telnet
or telnets
, which uses a TLS connection. If the protocol is not specified, it defaults to telnet
.
The options can be any option accepted by the net.connect or tls.connect functions of Node.js. For example, to create a TLS connection to a site with a self-signed certificate, this statement can be used:
const client = Telnet.client('telnets:some.example.com:8443', { rejectUnauthorized: false });
The factory method returns a Telnet.Connection
object, which is a subclass of Observable<Telnet.Event>
.
Listen for Events and Data
As an observable, the telnet connection can be subscribed to in order to receive data from the server. The default subscription publishes Telnet.Event
objects.
Client Events
All events have a timestamp
field that is a Date
object.
Telnet.Event.Connecting
Published when the client begins connecting to the server. The event has a connection
property for the client.
Telnet.Event.Connected
Published after a connection to the server has been established. The event has a connection
property for the client.
Telnet.Event.Disconnecting
Published when the client begins to disconnect from the server. The event has a connection
property for the client.
Telnet.Event.Disconnected
Published when the client has closed its connection to the server. The event has a connection
property for the client.
Telnet.Event.Data
Published when data is received from the server. The event has a data
field that is a string.
Telnet.Event.Command
Published when a telnet command has been received from the server. The event has a command
field that is a string of numbers.
Additional accessors are provided that act as filters for the Data
and Command
events. The data
accessor publishes each string of data. The commands
accessor publishes each array of numbers.
Listen for All Events
Events are all subclasses of Telnet.Event.
client.subscribe((event) => {
console.log('Received event:', event);
});
Listen for Data
The data will be returned as a string.
client.data.subscribe((data) => {
console.log('Received data:', data);
});
or
client.filter((event) => event instanceof Telnet.Event.Data).subscribe((event) => {
console.log('Received data:', event.data);
});
Listen for Commands
The commands will be an array of numbers.
client.commands.subscribe((command) => {
console.log('Received command:', command);
});
or
client.filter((event) => event instanceof Telnet.Event.Command).subscribe((event) => {
console.log('Received command:', event.command);
});
Listen for Errors
client.subscribe(
(event) => {
console.log('Received event:', event);
},
(error) => {
console.error('An error occurred:', error);
}
);
or
client
.catch((error) => {
console.error('An error occurred:', error);
})
.subscribe((event) => {
console.log('Received event:', event);
});
Connect
The connect
method must be called before any connections will be opened. Configuration errors, such as missing port numbers, will cause an exception to be thrown. Other errors will be reported on the error channel of the client observable.
Disconnect
The disconnect
method closes the connection to the server.
Telnet Server
Connections are created by using the Telnet.server
static factory method or createServer
function. This method takes two arguments
- The URI of the server to create
- Optionally, additional options to pass to the network socket
The URI should be in formats similar to protocol:host:port
. Only the port is required. Protocol can be either telnet
or telnets
, which uses a TLS connection. If the protocol is not specified, it defaults to telnet
. If the host is not specified, it defaults to 0.0.0.0
.
The options can be any option accepted by the net.createServer or tls.createServer functions of Node.js.
The factory method returns a Telnet.Server
object, which is a subclass of Observable<Telnet.Event>
.
Listen for Events
As an observable, the telnet connection can be subscribed to in order to receive data from the server. The default subscription publishes Telnet.Event
objects.
Server Events
All events have a timestamp
field that is a Date
object.
Telnet.Event.Connecting
Published when a client begins connecting to the server. The event has a connection
property for the client.
Telnet.Event.Connected
Published after a connection to the server has been established. The event has a connection
property for the client.
Telnet.Event.Disconnecting
Published when a client begins to disconnect from the server. The event has a connection
property for the client.
Telnet.Event.Disconnected
Published when a client has closed its connection to the server. The event has a connection
property for the client.
Telnet.Event.Starting
Published when the server begins starting up.
Telnet.Event.Started
Published after the server has started up.
Telnet.Event.Ending
Published when the server begins shutting down.
Telnet.Event.Ended
Published after the server has shut down.
Additional accessors are provided that act as filters for the Data
and Command
events. The data
accessor publishes each string of data. The commands
accessor publishes each array of numbers.
Start
The start
method must be called before the server will listen and any clients can connect. Configuration errors, such as missing port numbers, will cause an exception to be thrown. Other errors will be reported on the error channel of the server observable.
The method returns a promise that resolves to the [net.Server] to [tls.Server] object that underlies the connection, when the
listen
method's callback is invoked.
Stop
The stop
method will shutdown the server. First, it will call the disconnect
method on each connection. Then, it will close the server port.
The method returns a promise that resolves when the close
method's callback is invoked.
LINKS
AUTHOR
Eric Kidder