// [[file:m3u-player.org::*The script][The script:1]]
// @license magnet:?xt=urn:btih:cf05388f2679ee054f2beb29a391d25f4e673ac3&dn=gpl-2.0.txt GPL-v2-or-Later
const nodes = document.querySelectorAll("audio,video");
const playlists = {};
const prefetchedTracks = new Map(); // use a map for insertion order, so we can just blow away old entries.
// maximum prefetched blobs that are kept.
const MAX_PREFETCH_KEEP = 10;
// maximum allowed number of entries in a playlist to prevent OOM attacks against the browser with self-referencing playlists
const MAX_PLAYLIST_LENGTH = 1000;
const PLAYLIST_MIME_TYPES = ["audio/x-mpegurl", "audio/mpegurl", "application/vnd.apple.mpegurl","application/mpegurl","application/x-mpegurl"];
function stripUrlParameters(link) {
const url = new URL(link, window.location);
url.search = "";
url.hash = "";
return url.href;
}
function isPlaylist(link) {
const linkHref = stripUrlParameters(link);
return linkHref.endsWith(".m3u") || linkHref.endsWith(".m3u8");
}
function isBlob(link) {
return new URL(link, window.location).protocol == 'blob';
}
function parsePlaylist(textContent) {
return textContent.match(/^(?!#)(?!\s).*$/mg)
.filter(s => s); // filter removes empty strings
}
/**
* Download the given playlist, parse it, and store the tracks in the
* global playlists object using the url as key.
*
* Runs callback once the playlist downloaded successfully.
*/
function fetchPlaylist(url, onload, onerror) {
const playlistFetcher = new XMLHttpRequest();
playlistFetcher.open("GET", url, true);
playlistFetcher.responseType = "blob"; // to get a mime type
playlistFetcher.onload = () => {
if (PLAYLIST_MIME_TYPES.includes(playlistFetcher.response.type)) { // security check to ensure that filters have run
const reader = new FileReader();
const load = onload; // propagate to inner scope
reader.addEventListener("loadend", e => {
playlists[url] = parsePlaylist(reader.result);
onload();
});
reader.readAsText(playlistFetcher.response);
} else {
console.error("playlist must have one of the playlist MIME type '" + PLAYLIST_MIME_TYPES + "' but it had MIME type '" + playlistFetcher.response.type + "'.");
onerror();
}
};
playlistFetcher.onerror = onerror;
playlistFetcher.abort = onerror;
playlistFetcher.send();
}
function servedPartialDataAndCanRequestAll (xhr) {
if (xhr.status === 206) {
if (xhr.getResponseHeader("content-range").includes("/")) {
if (!xhr.getResponseHeader("content-range").includes("/*")) {
return true;
}
}
}
return false;
}
function prefetchTrack(url, onload) {
if (prefetchedTracks.has(url)) {
return;
}
// first cleanup: kill the oldest entries until we're back at the allowed size
while (prefetchedTracks.size > MAX_PREFETCH_KEEP) {
const key = prefetchedTracks.keys().next().value;
const track = prefetchedTracks.get(key);
prefetchedTracks.delete(key);
}
// first set the prefetched to the url so we will never request twice
prefetchedTracks.set(url, url);
// now start replacing it with a blob
const xhr = new XMLHttpRequest();
xhr.open("GET", url, true);
xhr.responseType = "blob";
xhr.onload = () => {
if (servedPartialDataAndCanRequestAll(xhr)) {
const endRange = Number(xhr.getResponseHeader("content-range").split("/")[1]) - 1;
const rangeXhr = new XMLHttpRequest();
rangeXhr.open("GET", url, true);
rangeXhr.responseType = "blob";
rangeXhr.setRequestHeader("range", "bytes=0-" + endRange);
rangeXhr.onload = () => {
prefetchedTracks.set(url, rangeXhr.response);
if (onload) {
onload();
}
};
rangeXhr.send();
} else {
prefetchedTracks.set(url, xhr.response);
if (onload) {
onload();
}
}
};
xhr.send();
}

function showStaticOverlay(mediaTag, canvas) {
if (mediaTag instanceof Audio) {
return;
}
// take screenshot of video and overlay it to mask short-term flicker.
const realWidth = mediaTag.getBoundingClientRect().width;
const realHeight = mediaTag.getBoundingClientRect().height;
canvas.width = realWidth;
canvas.height = realHeight;
// need the actual video size
const videoAspectRatio = mediaTag.videoHeight / mediaTag.videoWidth;
const tagAspectRatio = realHeight / realWidth;
const videoIsPartialHeight = tagAspectRatio > (videoAspectRatio * 1.01); // avoid rounding errors
const videoIsPartialWidth = videoAspectRatio > (tagAspectRatio * 1.01); // avoid rounding errors
if (videoIsPartialHeight) {
canvas.height = realWidth * videoAspectRatio;
} else if (videoIsPartialWidth) {
canvas.width = realHeight / videoAspectRatio;
}
const context = canvas.getContext("2d");
context.scale(canvas.width / mediaTag.videoWidth, canvas.height / mediaTag.videoHeight);
context.drawImage(mediaTag, 0, 0);
canvas.hidden = true;
mediaTag.parentNode.insertBefore(canvas, mediaTag.nextSibling);
canvas.style.position = "absolute";
// shift canvas to cover only the space where the video actually is
if (videoIsPartialWidth) {
canvas.style.marginLeft = "-" + ((realWidth + canvas.width) / 2.) + "px";
} else {
canvas.style.marginLeft = "-" + realWidth + "px";
}
if (videoIsPartialHeight) {
canvas.style.marginTop = ((realHeight - canvas.height) / 2.) + "px";
}
canvas.hidden = false;
}

function updateSrc(mediaTag, callback) {
const playlistUrl = mediaTag.getAttribute("playlist");
const trackIndex =  mediaTag.getAttribute("track-index");
// deepcopy playlists to avoid shared mutation
let playlist = [...playlists[playlistUrl]];
let trackUrl = playlist[trackIndex];
// download and splice in playlists as needed
if (isPlaylist(trackUrl)) {
if (playlist.length >= MAX_PLAYLIST_LENGTH) {
// skip playlist if we already have too many tracks
changeTrack(mediaTag, +1);
} else {
// do not use the cached playlist here, though it is tempting: it might genuinely change to allow for updates
fetchPlaylist(
trackUrl,
() => {
playlist.splice(trackIndex, 1, ...playlists[trackUrl]);
playlists[playlistUrl] = playlist;
updateSrc(mediaTag, callback);
},
() => callback());
}
} else {
let url = prefetchedTracks.has(trackUrl)
? prefetchedTracks.get(trackUrl) instanceof Blob
? URL.createObjectURL(prefetchedTracks.get(trackUrl))
: trackUrl : trackUrl;
const oldUrl = mediaTag.getAttribute("src");
// prevent size flickering by setting height before src change
const canvas = document.createElement("canvas");
if (!isNaN(mediaTag.duration) // already loaded a valid file
&& document.fullscreen !== true) { // overlay does not work for fullscreen
// mask flickering with a static overlay
try {
showStaticOverlay(mediaTag, canvas);
} catch (error) {
console.log(error);
}
}
// force sizes to stay constant during loading of the next segment
mediaTag.style.height = mediaTag.getBoundingClientRect().height.toString() + 'px';
mediaTag.style.width = mediaTag.getBoundingClientRect().width.toString() + 'px';
// swich to the next segment
mediaTag.setAttribute("src", url);
mediaTag.oncanplaythrough = () => {
if (!isNaN(mediaTag.duration)) { // already loaded a valid file
// unset element styles to allow recomputation if sizes changed
mediaTag.style.height = null;
mediaTag.style.width = null;
}
// remove overlay
canvas.hidden = true;
canvas.remove(); // to allow garbage collection
};
setTimeout(() => canvas.remove(), 300); // fallback
// replace the url when done, because a blob from an xhr request
// is more reliable in the media tag;
// the normal URL caused jumping prematurely to the next track.
if (url == trackUrl) {
prefetchTrack(trackUrl, () => {
if (mediaTag.paused) {
if (url == mediaTag.getAttribute("src")) {
if (mediaTag.currentTime === 0) {
mediaTag.setAttribute("src", URL.createObjectURL(
prefetchedTracks.get(url)));
}
}
}
});
}
// allow releasing memory
if (isBlob(oldUrl)) {
URL.revokeObjectURL(oldUrl);
}
// update title
mediaTag.parentElement.querySelector(".m3u-player--title").title = trackUrl;
mediaTag.parentElement.querySelector(".m3u-player--title").textContent = trackUrl;
// start prefetching the next three tracks.
for (const i of [1, 2, 3]) {
if (playlist.length > Number(trackIndex) + i) {
prefetchTrack(playlist[Number(trackIndex) + i]);
}
}
callback();
}
}
function changeTrack(mediaTag, diff) {
const currentTrackIndex = Number(mediaTag.getAttribute("track-index"));
const nextTrackIndex = currentTrackIndex + diff;
const tracks = playlists[mediaTag.getAttribute("playlist")];
if (nextTrackIndex >= 0) { // do not collapse the if clauses with double-and, that does not survive inlining
if (tracks.length > nextTrackIndex) {
mediaTag.setAttribute("track-index", nextTrackIndex);
updateSrc(mediaTag, () => mediaTag.play());
}
}
}

/**
* Turn a media tag into playlist player.
*/
function initPlayer(mediaTag) {
mediaTag.setAttribute("playlist", mediaTag.getAttribute("src"));
mediaTag.setAttribute("track-index", 0);
const url = mediaTag.getAttribute("playlist");
const wrapper = mediaTag.parentElement.insertBefore(document.createElement("div"), mediaTag);
const controls = document.createElement("div");
const left = document.createElement("button");
const title = document.createElement("span");
const right = document.createElement("button");
controls.appendChild(left);
controls.appendChild(title);
controls.appendChild(right);
left.classList.add("m3u-player--left");
right.classList.add("m3u-player--right");
title.classList.add("m3u-player--title");
title.style.overflow = "hidden";
title.style.textOverflow = "ellipsis";
title.style.whiteSpace = "nowrap";
// title.style.opacity = "1";
// title.style.direction = "rtl"; // for truncation on the left
// title.style.paddingLeft = "0.5em";
// title.style.paddingRight = "0.5em";
controls.style.display = "flex";
controls.style.justifyContent = "space-between";
const styleTag = document.createElement("style");
styleTag.innerHTML = ".m3u-player--left:hover, .m3u-player--right:hover {color: #ccc; background-color: #333}";
wrapper.appendChild(styleTag);
wrapper.appendChild(controls);
controls.style.width = mediaTag.getBoundingClientRect().width.toString() + "px";
// appending the media tag to the wrapper removes it from the outer scope but keeps the event listeners
wrapper.appendChild(mediaTag);
left.innerHTML = "◁"; // not textContent, because we MUST escape
// the tag here and textContent shows the
// escaped version
left.onclick = () => changeTrack(mediaTag, -1);
right.innerHTML = "▷";
right.onclick = () => changeTrack(mediaTag, +1);
fetchPlaylist(
url,
() => {
updateSrc(mediaTag, () => null);
mediaTag.addEventListener("ended", event => {
if (mediaTag.currentTime >= mediaTag.duration) {
changeTrack(mediaTag, +1);
}
});
},
() => null);
// keep the controls aligned to the media tag
mediaTag.resizeObserver = new ResizeObserver(entries => {
controls.style.width = entries[0].contentRect.width.toString() + "px";
});
mediaTag.resizeObserver.observe(mediaTag);
}
function processTag(mediaTag) {
const canPlayClaim = mediaTag.canPlayType('audio/x-mpegurl');
let supportsPlaylists = !!canPlayClaim;
if (canPlayClaim == 'maybe') { // yes, seriously: specced as you only know when you try
supportsPlaylists = false;
}
if (!supportsPlaylists) {
if (isPlaylist(mediaTag.getAttribute("src"))) {
initPlayer(mediaTag);
}
}
}
document.addEventListener('DOMContentLoaded', () => {
const nodes = document.querySelectorAll("audio,video");
nodes.forEach(processTag);
});
// @license-end
// The script:1 ends here