Protomux RPC Client

Connect to HyperDHT servers exposing protomux-rpc endpoints.

Manages connection state for you:
- Connections are opened lazily, when the first request is made
- The client will try re-connecting when the connection is lost
- Connections are automatically garbage-collected after a period of inactivity
- Supports suspend and resume functionality (for suspending network activity, such as when backgrounding on a phone)

Install

``
npm i protomux-rpc-client
`

Usage

For a quick-and-dirty client, simply initialise a ProtomuxRpcClient object, and call its makeRequest method (see API section for the contract).

For a cleaner approach, define a new class which exposes the available methods, abstracting away the encodings from the user. See the example.

API

#### const client = new ProtomuxRpcClient(dht, opts)

Create a new Protomux RPC Client instance. dht is a hyperDHT instance.

opts include:
- keyPair: use a specific keyPair to connect to the server, instead of the default one of the DHT instance.
- relayThrough: a function passed on to HyperDHT's connect method, to help relay when relevant. Default: null.
- backoffValues: an array of millisecond delays on reconnection attempts. The delay values are jittered. Default: [5000, 15000, 60000, 300000].
- suspended: a boolean for whether the client should be suspended on creation. Default: false
- requestTimeout default time (in ms) before a request rejects with a timeout error. Default: 10000.
- msGcInterval: how often to run the garbage collection. Connections are kept open for at least msGcInterval ms of inactivity.
- maxConcurrentPerService: maximum number of concurrent request per service. Default: 16.

#### client.opened

Whether the client is opened as a boolean.

#### client.closed

Whether the client is closed as a boolean.

#### client.suspended

Whether the client is currently suspended as a boolean.

#### client.dht

The HyperDHT instance used to make connections.

#### client.nrConnections

The number of servers with which the client is currently attempting to keep connections open.

#### await client.makeRequest(key, methodName, args, opts)

Creates a request to the server listening at the specified key (connecting if necessary) returning the response. methodName is a unique string that represents the method. args is the value(s) the method is called with.

Options:

`
{
requestEncoding, // Used to encode the args. Default: the protomux-rpc default.
responseEncoding, // Used to decode the response. Default: the protomux-rpc default.
id, // id of the protomux-rpc service
protocol, // protocol of the protomux-rpc service. Defaults to the server's public key.
timeout // time (in ms) before a request rejects with a timeout error. Defaults to the requestTimeout.
}
`

#### await client.suspend()

Suspends all open RPC clients, destroying their RPC channel.

#### await client.resume()

Resumes all suspended RPC clients by reconnecting.

#### await client.close()

Closes all RPC clients and cleans up.

#### await client.gc()

Forces a garbage collection. Normally never needed, since garbage collection runs at regular intervals.

#### client.on('gc', (nrRemoved) => {})

The gc events are emitted whenever one or more clients are garbage colllected. nrRemoved` indicates the amount of gc'd clients.