tildefriends/packages/cory/libunfurl/libunfurl.js

"use strict";

//! {"category": "libraries", "require": ["libhttp", "libxml"], "permissions": ["network"]}

let libxml = require("libxml");
let libhttp = require("libhttp");

let gEmbedIndex = 0;

async function unfurl(url) {
	let result = {href: url};
	let response = await libhttp.get(url);
	let parsed = libxml.StreamParser().parse(response.body);
	let oEmbedUrl;
	for (let node of parsed) {
		if (node.type == "element" && node.value == "link" && node.attributes.type == "application/json+oembed") {
			oEmbedUrl = node.attributes.href;
			break;
		}
	}

	if (oEmbedUrl) {
		response = await libhttp.get(oEmbedUrl);
		let oEmbed = JSON.parse(response.body);
		gEmbedIndex++;
		result = [{href: url}, "\n", {
			name: "oEmbed" + gEmbedIndex,
			iframe: `
	<span style="border: 0; padding: 0; margin: 0; overflow: hidden">
		${oEmbed.html}
	</span>
	<script language="javascript">
		let gResizeMeMessage = {
			event: "resizeMe",
			name: "oEmbed${gEmbedIndex}",
			width: -1,
			height: -1,
		};
		setInterval(function() {
			if (document.body.scrollHeight != gResizeMeMessage.height
				|| document.body.scrollWidth != gResizeMeMessage.width) {
				gResizeMeMessage.width = document.body.scrollWidth;
				gResizeMeMessage.height = document.body.scrollHeight;
				parent.postMessage(gResizeMeMessage, "*");
			}
		}, 100);
	</script>
`,
			width: oEmbed.width || 320,
			height: oEmbed.height || 120,
			style: "margin: 0; padding: 0; border: 0; overflow: hidden",
		}];
	}

	return result;
}

async function test() {
	terminal.print(await unfurl("https://twitter.com/511nyAlbany/status/777221230915096576"));
	terminal.print(await unfurl("https://www.youtube.com/watch?v=pTA0DSfrGZ0"));
}

//test().catch(terminal.print);

core.register("onMessage", function(sender, message) {
	return unfurl(message).catch(error => [message, "(error retrieving: ", error, ")"]);
});