@parasaurolophus/node-red-dnssd

Wrap
@gravitysoftware/dnssd
for use in Node-RED.


This provides a superset of the functionality supported by
node-red-node-discovery,
without generating any warnings in the Node-RED log.

Tested with Node-RED 3.1 running on Node.js 20.x. May not be compatible with
older versions.

---

dnssd-advertisement

$3

msg.payload.command specifies a dnssd.Advertisement method to invoke:

#### start

Start responding to service enquiries from browsers.

``json
{ "payload": {
"command": "start"
[, "service": name]
[, "udp": boolean]
[, "port": number]
[, "options": json]
}
}
`

If the optional service name, udp, port number or options values are
provided, they will override the node's configuration.

#### stop

Broadcast a "service down" event.

`json
{ "payload": { "command": "stop" } }
`

#### updateTXT

Update the TXT record. (Note that this is provided for completeness but is of
limited utility since it does not trigger any of the events exposed by the
dnssd.Browser object.)

`json
{
"payload": {
"command": "updateTXT",
"txt": {
"foo": "bar"
}
}
}
`

$3

1. Stream of Advertiser.instanceRenamed() events
2. Stream of Advertiser.hostRenamed() events
3. Stream of Advertiser.stopped() events
3. Stream of Advertiser.error() events

---

dnssd-browser

$3

msg.payload.command specifies a dnssd.Browser method to invoke:

#### start

Begin listening for service life-cycle events.

`json
{
"payload": {
"command": "start"
[, "service": name]
[, "udp": boolean]
}
}
`

If the optional service name or udp values are provided, they will override the node's configured values.

#### stop

Stop listening for service life-cycle events.

`json
{ "payload": { "command": "stop" } }
`

#### list

Send a list of running services.

`json
{ "payload": { "command": "list" } }
`

$3

1. Stream of Browser.serviceUp() events
2. Stream of Browser.serviceDown() events
3. Stream of Browser.error() events
4. Browser.list() results

---

Details

This is a deliberately thin wrapper around the functionality exposed by
@gravitysoftware/dnssd,
which is a pure JavaScript implementation of DNS-SD.

The _Service_ configuration string is the name of the DNS-SD service to
broadcast using dnssd-advertisement or watch using dnssd-browser.

By default, these nodes will use TCP. The _Use UDP?_ configuration checkbox
tells them to use UDP instead.

dnssd-advertisement also requires a _Port_ number and can optionally take
_Options_, including a txt record. _Options_ may be specified using JSON or
JSONata.

These nodes do not start automatically even if they are fully configured. Use
inject` nodes configured to send messages when flows are (re-) started if
required for your purposes.