alanshawit-ws
Simple async iterables for websocket client connections
Table of contents
Install
$ npm i it-ws
Browser <script> tag
Loading this module through a script tag will make it's exports available as ItWs in the global namespace.
<script src="https://unpkg.com/it-ws/dist/index.min.js"></script>
Usage
Example - client
import { connect } from 'it-ws/client'
import { pipe } from 'it-pipe'
const stream = connect(WS_URL)
await stream.connected() // Wait for websocket to be connected (optional)
pipe(source, stream, sink)
Example - server
import { createServer } from 'it-ws/server'
import { pipe } from 'it-pipe'
const server = createServer(stream => {
//pipe the stream somewhere.
//eg, echo server
pipe(stream, stream)
})
await server.listen(PORT)
API
import { connect } from 'it-ws/client'
connect(url, { binary: boolean })
Create a websocket client connection. Set binary: true to get a stream of arrayBuffers (on the browser). Defaults to true on node, but to strings on the browser. This may cause a problems if your application assumes binary.
For adding options to the WebSocket instance, as websockets/ws/blob/master/doc/ws.md#new-websocketaddress-protocols-options, you can provide an object with the websocket property into the connect options.
const stream = connect(url)
// stream is duplex and is both a `source` and `sink`.
// See this for more information:
// https://gist.github.com/alanshaw/591dc7dd54e4f99338a347ef568d6ee9#duplex-it
import { createServer } from 'it-ws/server'
Create async iterable websocket servers.
createServer(options?, onConnection)
options takes the same server options as ws module
onConnection(stream) is called every time a connection is received.
Example
One duplex service you may want to use this with is muxrpc
import { createServer } from 'it-ws/server'
import { connect } from 'it-ws/client'
import { pipe } from 'it-pipe'
createServer({
onConnection: (stream) => {
// pipe duplex style to your service
pipe(stream, service.createStream(), stream)
}
})
.listen(9999)
const stream = client.createStream()
await pipe(
stream,
connect('ws://localhost:9999'),
stream
)
if the connection fails, the stream will throw
try {
await pipe(
stream,
connect('ws://localhost:9999'),
stream
)
} catch (err) {
// handle err
}
To run the server over TLS:
createServer({
key: fs.readFileSync('test/fixtures/keys/agent2-key.pem'),
cert: fs.readFileSync('test/fixtures/keys/agent2-cert.pem')
// other options
})
.listen(9999)
To add client-authentication to the server, you can set verifyClient.
Documentation here.
function verifyClient (info) {
return info.secure == true
}
createServer({
verifyClient: verifyClient
// other options
})
use with an http server
if you have an http server that you also need to serve stuff
over, and want to use a single port, use the server option.
import http from 'http'
const server = http.createServer(function(req, res){...}).listen(....)
createServer({
server: server
// other options
})
core, websocket wrapping functions
these modules are used internally, to wrap a websocket. you probably won't need to touch these, but they are documented anyway.
import duplex from 'it-ws/duplex'
turn a websocket into a duplex stream.
If provided, opts is passed to sink(socket, opts).
WebSockets do not support half open mode. see allowHalfOpen option in net module
If you have a protocol that assumes halfOpen connections, but are using a networking protocol like websockets that does not support it, I suggest using it-goodbye with your protocol.
The duplex stream will also contain a copy of the properties from
the http request that became the websocket. they are method, url,
headers and upgrade.
also exposed at: import { duplex } from 'it-ws'
import sink from 'it-ws/sink'
Create a Sink that will write data to the socket.
opts may be {closeOnEnd: true, onClose: onClose}.
onClose will be called when the sink ends. If closeOnEnd=false
the stream will not close, it will just stop emitting data.
(by default closeOnEnd is true)
If opts is a function, then onClose = opts; opts.closeOnEnd = true.
import sink from 'it-ws/sink'
import { pipe } from 'it-pipe'
import each from 'it-foreach'
import delay from 'delay'
// connect to the echo endpoint for test/server.js
var socket = new WebSocket('wss://echo.websocket.org')
// write values to the socket
pipe(
async function * () {
while (true) {
yield 'hello @ ' + Date.now()
}
}(),
// throttle so it doesn't go nuts
(source) => each(source, () => delay(100))
sink(socket)
);
socket.addEventListener('message', function(evt) {
console.log('received: ' + evt.data);
});
also exposed at import { sink } from 'it-ws'
import source from 'it-ws/source'
Create a Source that will read data from the socket.
import { pipe } from 'it-pipe'
import source from 'it-ws/source'
import { toString } from 'uint8arrays/to-string'
pipe(
// connect to the test/server.js endpoint
source(new WebSocket('ws://localhost:3000/read')),
async (source) => {
for await (const buf of source) {
console.info(toString(buf))
}
}
);
also exposed at import { source } from 'it-ws'
License
Licensed under either of
- Apache 2.0, (LICENSE-APACHE / http://www.apache.org/licenses/LICENSE-2.0)
- MIT (LICENSE-MIT / http://opensource.org/licenses/MIT)
Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.