mastodon/public/embed.js

131 lines
3.5 KiB
JavaScript

// @ts-check
const allowedPrefixes = (document.currentScript && document.currentScript.tagName.toUpperCase() === 'SCRIPT' && document.currentScript.dataset.allowedPrefixes) ? document.currentScript.dataset.allowedPrefixes.split(' ') : [];
(function () {
'use strict';
/**
* @param {() => void} loaded
*/
var ready = function (loaded) {
if (document.readyState === 'complete') {
loaded();
} else {
document.addEventListener('readystatechange', function () {
if (document.readyState === 'complete') {
loaded();
}
});
}
};
/**
* @param {Map} map
*/
var generateId = function (map) {
var id = 0, failCount = 0, idBuffer = new Uint32Array(1);
while (id === 0 || map.has(id)) {
id = crypto.getRandomValues(idBuffer)[0];
failCount++;
if (failCount > 100) {
// give up and assign (easily guessable) unique number if getRandomValues is broken or no luck
id = -(map.size + 1);
break;
}
}
return id;
};
ready(function () {
/** @type {Map<number, HTMLQuoteElement | HTMLIFrameElement>} */
var embeds = new Map();
window.addEventListener('message', function (e) {
var data = e.data || {};
if (typeof data !== 'object' || data.type !== 'setHeight' || !embeds.has(data.id)) {
return;
}
var embed = embeds.get(data.id);
if (embed instanceof HTMLIFrameElement) {
embed.height = data.height;
}
if (embed instanceof HTMLQuoteElement) {
var iframe = embed.querySelector('iframe');
if (!iframe || ('source' in e && iframe.contentWindow !== e.source)) {
return;
}
iframe.height = data.height;
var placeholder = embed.querySelector('a');
if (!placeholder) return;
embed.removeChild(placeholder);
}
});
// Legacy embeds
document.querySelectorAll('iframe.mastodon-embed').forEach(iframe => {
var id = generateId(embeds);
embeds.set(id, iframe);
iframe.allow = 'fullscreen';
iframe.sandbox = 'allow-scripts allow-same-origin';
iframe.style.border = 0;
iframe.style.overflow = 'hidden';
iframe.style.display = 'block';
iframe.onload = function () {
iframe.contentWindow.postMessage({
type: 'setHeight',
id: id,
}, '*');
};
iframe.onload(); // In case the script is executing after the iframe has already loaded
});
// New generation of embeds
document.querySelectorAll('blockquote.mastodon-embed').forEach(container => {
var id = generateId(embeds);
embeds.set(id, container);
var iframe = document.createElement('iframe');
var embedUrl = new URL(container.getAttribute('data-embed-url'));
if (embedUrl.protocol !== 'https:' && embedUrl.protocol !== 'http:') return;
if (allowedPrefixes.every((allowedPrefix) => !embedUrl.toString().startsWith(allowedPrefix))) return;
iframe.src = embedUrl.toString();
iframe.width = container.clientWidth;
iframe.height = 0;
iframe.allow = 'fullscreen';
iframe.sandbox = 'allow-scripts allow-same-origin';
iframe.style.border = 0;
iframe.style.overflow = 'hidden';
iframe.style.display = 'block';
iframe.onload = function () {
iframe.contentWindow.postMessage({
type: 'setHeight',
id: id,
}, '*');
};
container.appendChild(iframe);
});
});
})();