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Channel Targeting

You never type a channel name or URL. The extension works out which of your open tabs is a CyTube channel, ranks the candidates, and then verifies the guess from inside the page before emitting anything.

Why targeting works this way

Section titled “Why targeting works this way”

CyTube is self-hosted as often as it is used on cytu.be, so there is no single host to hardcode. And because the extension deliberately holds no credentials, it has to reach the channel through a tab that is already connected. Detection is therefore heuristic on the outside and verified on the inside.

Step 1: Candidate detection

Section titled “Step 1: Candidate detection”

chrome.tabs.query({}) returns every tab. A tab survives filtering if it has an integer ID, an http:// or https:// URL, and passes isLikelyCyTubeTab:

const haystack = `${tab.title || ""} ${tab.url || ""}`.toLowerCase();


if (haystack.includes("cytube") || haystack.includes("cytu.be")) {
  return true;
}


const parsed = new URL(tab.url);
return /^\/r\/[a-z0-9_-]+$/i.test(parsed.pathname);

So a tab qualifies if its title or URL mentions cytube or cytu.be, or if its path looks like a CyTube channel route (/r/<channel>). That second rule is what makes self-hosted instances on arbitrary domains work without configuration.

Step 2: Ranking

Section titled “Step 2: Ranking”

Candidates are scored and sorted highest-first; ties break by the tab’s window position:

Signal in title or URL Points
contains cytube +5
contains cytu.be +4
contains /r/ +3

The scores are additive, so a cytu.be/r/example tab scores 12 and outranks a tab that merely mentions CyTube in its title. The dropdowns list every candidate as <title> - <host> so you can override the ranking.

Selection then works like this:

  • If lastTargetTabId is still among the candidates, it wins.
  • Otherwise the top-ranked candidate is used.
  • If there are no candidates at all, you get Open your CyTube channel in another tab first.

Step 3: Site access for that origin

Section titled “Step 3: Site access for that origin”

Before injecting, the origin of the chosen tab is turned into a pattern (https://example.org/*) and checked with chrome.permissions.contains. If it is missing, chrome.permissions.request prompts you - one host, once.

Nothing is granted broadly ahead of time. The manifest lists only optional_host_permissions, so a fresh install can reach no site until you point it at one.

Step 4: Verification inside the page

Section titled “Step 4: Verification inside the page”

chrome.scripting.executeScript runs a single function in the target tab with world: "MAIN", which is what lets it see CyTube’s own page globals rather than an isolated content-script world. That function refuses to proceed unless all of these hold:

Check Rejection message
window.socket exists with an emit function This page does not expose an active CyTube socket.
window.CHANNEL.name is a string This tab is not a CyTube channel page.
socket.disconnected is falsy CyTube is disconnected in the selected tab.
window.hasPermission("playlistadd") (when available) Your current CyTube user cannot add videos in this channel.
window.hasPermission("playlistnext") for pos: "next" Position-specific refusal

Only after all of those does it emit:

socket.emit("queue", { id: videoId, type: "yt", pos: position, temp });

Step 5: Confirming the result

Section titled “Step 5: Confirming the result”

The injected function attaches temporary queue and queueFail listeners before emitting, then resolves on whichever fires first, with a 5-second timeout.

A queue packet only counts as yours when item.media.type === "yt", the media ID matches, and - if window.CLIENT.name is readable - item.queueby equals your name. Listeners are always detached afterwards via socket.off or socket.removeListener, whichever the page’s socket.io build provides.