@tykuhn2/gateway v1.1.0

GERTe Gateway (NodeJS)

This repository is dedicated to the NodeJS version of the GERTe Gateway
For more information on GERTe or its gateways see the main repository.

Installing

Simply install the npm package (npm i gerte or other methods) and require it.

Usage

The API provided by this package has two parts: Config and Connection.

Reading Configuration

The API can read configuration files often distributed with GERTe gateways via the Config function exported by the main file.
To read a configuration file, simply pass the filename into the Config function which will then attempt to synchronously read the file and return an array of "peers" it finds within the file.
The peer objects have three values: ip, gport, and pport. For the purposes of this API, only ip and gport are needed.

Connecting to GEDS

The main file exports a class called Connection which, when constructed, connects to and negotiates with the selected GEDS server.
To construct a Connection call new Connection(port, ip) where port is a number and ip is a string.

The Connection class has the following events: error, connected, status, registered, data, and close. Socket errors beyond ECONNRESET, ECONNREFUSED, and ETIMEDOUT will be emitted by the Connection class as well.

Events

Most applications will only require the registered and data events, with close and error for safety. connected, and status are not required as the internal implementation will use them.

Registering an Address

This documentation assumes you already have an address from the GERT maintainers.
In order to register an address, call Connection.register(address, key) where address is a string with a valid GERTe dot format address and key is a valid 20-byte string.
If the gateway has not finished negotiating the registration will be deferred until the negotiation is complete.

Once registration is complete, the Connection object will emit a registered event with the address as an argument.

The current address as known by the gateway can be retrieved from Connection.address.
Note: This address can be either an empty string if no known address is registered, unknown if the address is unknown due to a reported error, or a GERTe dot format address.

Sending Data

Reminder: Sending and receiving data requires being registered
Prior to sending data, ensure the registered event has been thrown
To send data call Connector.send(tgt, src, data) where tgt is a dot-colon format GERTc address, src is a dot format GERTi address, and data is either a string or a buffer.
Data cannot exceed 255 bytes excluding headers

The function will return a promise. The promise will be resolved on a positive response from GEDS or rejected with the error message on a negative response from GEDS.

Receiving Data

Reminder: Sending and receiving data requires being registered
When the API receives data from GEDS it will be parsed into an object and emitted in a data event.
The data object has three values: source, target, data.
The source address is a GERTc dot-colon format address from which the message was sent, the target address is a GERTc dot-colon format address to which the message is addressed, and data is a buffer of the data received.

Closing the Connection

Whilst NodeJS and GEDS should be able to handle practically any form of closure, a safe way to ensure the address is freed is to call Connection.close() and await the close event.
Calling Connection.close() immediately sends a close request to GEDS and shutdowns the writing functionality of the connection. The close event will be thrown once GEDS responds to the request.

Licensing

The project is currently listed as UNLICENSED otherwise known as "all rights reserved."
This has more to do with a rush to publish and less to do with restrictions on modifications. General rule: play nice.
Give credit where credit is due, be willing to submit your changes to this repository, do not "steal" outside reasonable redistribution, etc.

Officially all rights are reserved but if you play nice there is no reason to worry.