OSCQuery for Node

An implementation of the OSCQuery proposal for Node.js, written in TypeScript.

Installation

npm install oscquery

Simple example

import {
	OSCQueryServer,
	OSCTypeSimple,
	OSCQAccess,
} from "oscquery";

const service = new OSCQueryServer();

service.addMethod("/foo", {
	description: "demonstrates a read-only OSC node- single float value ranged 0-100",
	access: OSCQAccess.READONLY,
	arguments: [
		{ 
			type: OSCTypeSimple.FLOAT,
			range: { min: 0, max: 100},
		}
	]
});
service.setValue("/foo", 0, 0.5);

service.addMethod("/bar", {
	description: "demonstrates a read/write OSC node- two ints with different ranges",
	access: OSCQAccess.READWRITE,
	arguments: [
		{
			type: OSCTypeSimple.INT,
			range: { min: 0, max: 50 },
		},
		{
			type: OSCTypeSimple.INT,
			range: { min: 51, max: 100 },
		}
	]
});
service.setValue("/bar", 0, 4);
service.setValue("/bar", 1, 51);

service.start();

More examples can be found in the examples/ directory.

Supported extensions

The proposal outlines several extensions, of which this library implements a few but not all. Every extension that is implemented should have full compliance with the spec however, including all their optional features.

| Extension | Supported | | --- | --- | | ACCESS | ✅ | | VALUE | ✅ | | RANGE | ✅ | | DESCRIPTION | ✅ | | TAGS | ✅ | | EXTENDED_TYPE | ❌ | | UNIT | ❌ | | CRITICAL | ✅ | | CLIPMODE | ✅ | | OVERLOADS | ❌ | | HTML | ❌ | | Bi-Directional Communication | ❌ |

Classes & Methods

OSCQueryServer

constructor(opts?)
Creates a new instance of the server. The options object has the following fields (all optional):

• httpPort: Port that the HTTP server should bind itself to. If it is not specified, a random free port will be chosen.
• bindAddress: Address to bind the server to. If it is not specified, the server will bind itself to all interfaces.
• rootDescription: DESCRIPTION attribute of the root node.
• oscQueryHostName: NAME field of the HOST_INFO attribute
• oscIp: OSC_IP field of the HOST_INFO attribute. If not specified, the bindAddress is used instead.
• oscPort: OSC_PORT field of the HOST_INFO attribute. If not specified, the httpPort is used instead.
• oscTransport: OSC_TRANSPORT of the HOST_INFO attribute. (Default: "UDP")
• serviceName: Name of the mDNS service. (Default: "OSCQuery")

start(): Promise<HostInfo>
Starts the HTTP server and mDNS service to advertise its existence on the network. Resolves to the host info it will use for the HOST_INFO attribute. This can be used to find the port it landed on, in case the httpPort option was not set in the constructor.

stop(): Promise<void>
Stops the HTTP server and mDNS service.

addMethod(path: string, params: OSCMethodDescription)
Adds a new OSC method accessible under the given path. The method description object is documented below.

removeMethod(path: string)
Removes an OSC method accessible under the given path. This will remove all empty nodes in the respective branch as well. Example: If a service as two methods /foo/ and /bar/baz and you remove /bar/baz, the /bar node will also be removed since it would otherwise be an empty container.

setValue(path: string, arg_index: number, value: unknown)
Sets the VALUE attribute for the method of the given path and the argument with the given index.

unsetValue(path: string, arg_index: number)
Removes the VALUE attribute for the method of the given path and the argument with the given index. This is different from setting it to null, since some methods actually take a null type as their argument. Unsetting it will completely remove the VALUE attribute in case all arguments are unset.

OSCQueryDiscovery

start()
Start the mDNS browser to find OSCQuery services on the network. If the browser finds one, an up event will be emitted, and if a service announces it is shutting down, a down event will be emitted (both documented below).

stop()
Stops the mDNS browser, preventing new services from being discovered.

getServices(): DiscoveredService[]
Returns a list of all currently discovered services.

queryNewService(address: string, port: number): Promise<DiscoveredService>
This method is normally called internally by the mDNS browser every time a new service is discovered. If you already know the address and port of a service however, this method can be used to query it manually.

Events

up
Emitted every time a new service is discovered and queried. The handler is called with a single DiscoveredService argument.

down
Emitted every time a service announces its departure. The handler is called with a single DiscoveredService argument.

OSCMethodDescription

The fields in this object correspond almost 1:1 to the attributes in the OSCQuery nodes. The main difference are the arguments, which are essentially a wrapper around attributes such as TYPE, VALUE, etc. Instead of defining them all as arrays, each argument is its own object with all the relevant metadata directly attached to it.

interface OSCMethodDescription {
	full_path?: string, // only used in the for the discovery
	description?: string;
	access?: OSCQAccess,
	tags?: string[],
	critical?: boolean,
	arguments?: OSCMethodArgument[];
}

OSCMethodArgument

interface OSCMethodArgument {
	type: OSCType,
	range?: OSCQRange,
	clipmode?: OSCQClipmode,
	value?: unknown,
}

DiscoveredService

readonly address: string
The network address of this service.

readonly port: number
The port this service announced.

get hostInfo: HostInfo
A parsed version of the HOST_INFO attribute.

get nodes: OSCNode
The root node of a tree representation of the OSCQuery nodes. Calling .serialize() on the nodes will return a JSON object representing the node itself and all children.

flat(): OSCMethodDescription[]
Create a flat list of all methods this service has to offer. Using this method is recommended instead of traversing the node tree manually.

update(): Promise<void>
Refreshes the HOST_INFO and nodes by calling the respective HTTP endpoints again.

resolvePath(path: string): OSCNode | null
Resolves a path from the node tree or returns null if the path does not exist.

OSCNode

Most of the methods on this class are not designed to be called from the outside, so this documentation is only going to document the most common properties and methods.

readonly name: string
The name (i.e. path component) of the node.

getValue(arg_index: number): unknown
Retrieves the VALUE with the specified index, or null if it is not set.

serialize(): SerializedNode
Serializes the node (and all children) into a simple object which matches the http response to a query without a specific attribute in the query part of the URL.