dweb-loader/index.js

JSON-LD document loader for IPFS and IPLD URIs

const CID = require("cids")

async function ipldLoader(ipfs, path, documentUrl) {
	const cid = new CID(path)
	if (cid.codec === "dag-cbor") {
		const { value } = await ipfs.dag.get(path)
		return { document: value, documentUrl }
	} else {
		throw new Error("Unsupported IPLD codec")
	}
}

async function ipfsLoader(ipfs, path, documentUrl) {
	let doc = ""
	for await (const chunk of ipfs.cat(path)) {
		doc += chunk.toString()
	}
	return { document: JSON.parse(doc), documentUrl }
}

const documentLoaders = {
	"ipld://": ipldLoader,
	"dweb:/ipld/": ipldLoader,
	"ipfs://": ipfsLoader,
	"dweb:/ipfs/": ipfsLoader,
}

const prefixes = Object.keys(documentLoaders)

module.exports = (ipfs) => async (url, options) => {
	const prefix = prefixes.find((prefix) => url.indexOf(prefix) === 0)
	if (prefix) {
		return documentLoaders[prefix](ipfs, url.slice(prefix.length), url)
	} else {
		throw new Error("Could not load document", url)
	}
}