Wardrobe — install several themes and let every member pick one
Flarum compiles every enabled extension's LESS into a single forum.css, and every extension's JavaScript into a single forum.js. Enable two themes at once and you get both stylesheets fighting in one file and both themes' components rendering for everyone — which is why a forum has always been one theme for everybody.
Wardrobe compiles those same sources once per theme, each time with every other theme left out of both bundles, and serves each visitor the pair that belongs to their choice.
No theme has to be modified, and core is not patched.
Same forum, same moment, two different members. Not a recolour — each one gets that theme's stylesheet and its JavaScript, so its components render and the other theme's do not.
What people get
A theme switcher in the header, one click, for members and guests:
A picker on the member settings page, with "Use the forum's theme" as its first option:
A member's choice is stored as a preference, so it follows them between devices. A guest's is a cookie that the server reads on the next request — so a guest gets a properly themed page rather than one repainted after boot. No cookie is written until a guest actually picks something, so untouched guest pages stay byte-identical and cacheable.
What admins get
Tick which installed themes the forum offers, pick the default, or turn member choice off entirely to hold one look:
Themes are detected from the flarum-extension.category each extension declares, so you never type an extension id.
Theme add-ons travel with their theme: an extension that requires a theme is left out wherever that theme is, so an add-on never loads reaching for exports that aren't there.
What it costs
Measured on a forum with 60+ extensions, a Valkey cache and a queue worker:
- 0.11 ms added to a page request at p50 (0.16 ms p90) — against a 70 ms page. With and without the extension enabled, page latency over 50 requests was 70.2 ms vs 70.4 ms: indistinguishable.
- Compiling a theme costs 450 ms of LESS, and it happens on the queue, off the request path. Forums with no worker fall back to compiling on first use; nothing breaks.
- A rebuild that changes nothing leaves every member's cached stylesheet alone — the revision only moves when the bytes a client would download actually change.
- A burst of traffic arriving on a stale theme produces one compile per theme, not one per request.
- Each member's stylesheet is smaller than today's shared one, because it carries one theme instead of all of them. On the test forum: 581 KB shared, versus 519 KB and 546 KB for the two per-theme sheets — each with zero rules from the other theme.
Themes are compiled whole, never as a shared sheet plus a per-theme delta. A theme that overrides core LESS variables (one of the two test themes overrides seven) would silently stop working if its overrides were compiled apart from the rules they target.
Notes
- Switching theme reloads the page. It has to — the running page is the other theme's JavaScript, not just its colours.
- If you run a full-page cache in front of Flarum, add the
wardrobe_theme cookie to its cache key.
- English and Spanish included.
Install
composer require ernestdefoe/wardrobe
