feat: add initial CBOR codec support

[JKRhb]

Corresponding with #953, this PR adds initial support for CBOR encoding and decoding. For now, the Codec is added to the core package, but as discussed in the issue, it should probably be moved to its own codec-cbor package, either in this PR or a follow-up.

Future additions to the codec should include support for custom tag encoding/decoding¹, but for now, at least all basic JavaScript data types should be supported (via the cbor package).

Footnotes

1. See RFC 8949, section 3.4 for more information on CBOR tags (sorry for confusing the purpose of tags a bit at the community meetup on Thursday 😅). ↩

[egekorkan]

I have tested and it indeed works. I have used the following script

const { Servient, Helpers } = require("@node-wot/core");
const { CoapClientFactory } = require("@node-wot/binding-coap");
const { HttpClientFactory } = require("@node-wot/binding-http");

// create Servient and add CoAP binding
const servient = new Servient();
servient.addClientFactory(new CoapClientFactory());
servient.addClientFactory(new HttpClientFactory());

const td = {
    "@context": "https://www.w3.org/2022/wot/td/v1.1",
    title: "CborTestThing",
    securityDefinitions: {
        nosec_sc: { scheme: "nosec" },
    },
    security: "nosec_sc",
    properties: {
        test1: {
            forms: [
                {
                    href: "coap://californium.eclipseprojects.io/multi-format",
                    contentType: "application/cbor",
                    "cov:accept": 60,
                },
            ],
        },
        test2: {
            forms: [
                {
                    href: "coap://californium.eclipseprojects.io/multi-format",
                    contentType: "application/json",
                    "cov:accept": 50,
                },
            ],
        },
        test3: {
            forms: [
                {
                    href: "http://plugfest.thingweb.io:8083/testthing/properties/bool",
                    contentType: "application/json",
                },
            ],
        },
    },
};

const wotHelper = new Helpers(servient);

async function main() {
    const WoT = await servient.start();
    const thing = await WoT.consume(td);

    // read property
    const read1 = await thing.readProperty("test1");
    console.log("value1 is: ", await read1.value());

    const read2 = await thing.readProperty("test2");
    console.log("value2 is: ", await read2.value());

    const read3 = await thing.readProperty("test3");
    console.log("value3 is: ", await read3.value());
}

main()

I get:

value1 is: { mid: 54248, code: 'GET', type: 'CON', accept: 60 }
value2 is: { type: 'CON', code: 'GET', mid: 37042, accept: 50 }
value3 is: false

[egekorkan]

@JKRhb could you also change the readme at https://github.com/eclipse/thingweb.node-wot/blob/master/README.md?plain=1#L79

[JKRhb]

Thank you for testing! :)

@JKRhb could you also change the readme at https://github.com/eclipse/thingweb.node-wot/blob/master/README.md?plain=1#L79

Done in 1e3e895 :)

[danielpeintner]

LGTM

[relu91]

Awesome! 🥳