ILP Plugin BTP

> One plugin to rule them all

 

Used right out of the box, this plugin is capable of representing a data
channel with no money involved. It will send BTP messages with no knowledge
of the data within, so it can be used for ILP packets. The sendMoney function
is a no-op, because there is no system involved handling money.

The main use of this plugin, however, is as a building block for plugins that
do have an underlying ledger. In this way, it's the successor of
ilp-plugin-payment-channel-framework

Plugins that sub-class the AbstractBtpPlugin should override sendMoney and _handleMoney at least.

Use as a Data Channel for ILP

``js
const server = new BtpPlugin({
listener: {
port: 9000,
secret: 'shh_its_a_secret'
}
})

await server.connect()

const client = new BtpPlugin({
server: 'btp+ws://:shh_its_a_secret@localhost:9000'
})

await client.connect()

server.registerDataHandler(serverHandler)
client.registerDataHandler(clientHandler)

await client.sendData(IlpPacket.serializeIlpPrepare({
// ...
})
`

Use as a Base Class for a New Plugin

Two functions must be defined in order for the plugin to handle money.

* sendMoney (amount: string) -> Promise: sends amount of units to the peer. This should be done via a BTP TRANSFER call.
* _handleMoney (from: string, btpPacket: BtpPacket) -> Promise>: This function is called on an incoming BTP TRANSFER.

BtpSubProtocol is made up of:

* protocolName: string: The name of this side protocol. ILP-level information must be named ilp.
* contentType: number: The content type. 0 is application/octet-stream, 1 is text/plain-utf8, and 2 is application/json. Mainly used for logging and smart deserializing.
* data: buffer`: The actual protocol data.