Hashtags
Freeform hashtags for Flarum 2. Write #anything in a post and it becomes a link to a feed of every discussion using it. No admin setup, no pre-created tags, nothing to configure — if somebody types it, it exists.
That one line is the whole design. #gameday and #upsetalert are freeform hashtags nobody created in advance. General is a real Flarum tag, and it still renders as a tag mention. Both use #, in the same sentence, and neither gets in the other's way.
It does not fight flarum/mentions
flarum/mentions already uses # for tag mentions, so the obvious assumption is that a hashtag extension has to patch it, disable it, or move one of the two onto a different symbol.
It doesn't. This extension does not touch flarum/mentions at all. Both matchers are registered and position in the text decides:
| You write | A tag with that slug exists | No such tag |
|---|
#general | tag mention, links to /t/general | freeform hashtag |
#foryourpage | — | freeform hashtag, links to /hashtag/foryourpage |
Core's tag-mention pattern consumes the character before the #, so its tag begins one byte earlier in the text, and s9e/TextFormatter offers it the text first. If the slug is a real tag it wins and the cursor moves past it. If it isn't, the mention invalidates itself without moving the cursor, and the hashtag claims the same position.
Precedence is therefore positional, which means it doesn't depend on extension load order. A tag slug is never shadowed by a hashtag, and a hashtag never has to be registered in advance.
Autocomplete, shared with your tags
Typing # offers existing hashtags and tags in a single dropdown — that's #speedr matching the Speedrun tag and the #speedrunfriday hashtag at once. It registers onto core's existing # format rather than adding a competing trigger, so there is one symbol and one list.
This isn't decoration. It's what makes a freeform namespace work: without suggestions you end up with #gameday, #GameDay and #game-day as three separate feeds inside a week, because nobody can see what already exists while they type.
A feed per hashtag, and a page to browse them
/hashtag/:name is a stock discussion list driven by a hashtag: search filter, so visibility scoping, pagination and the sort dropdown are Flarum's own rather than a reimplementation. A hashtag used only inside discussions you can't see gives you an empty feed.
/hashtags browses everything currently in use, with search and popular / recently used / A–Z. Both pages are linked from the index navigation, and hashtag:gameday / -hashtag:gameday work in the search box.
Details that matter
- Case-insensitive matching, case-preserving display.
#GameDay and #gameday are one hashtag with one feed and one canonical URL, but each post renders the casing its author typed.
- Safe by default. Nothing is matched inside code spans, fenced blocks or indented blocks; a
#fragment in a URL is left alone; C#, F# and foo#bar never match; #42 is left for issue-reference extensions.
- Unicode.
#café, #日本語 and #multi-word-thing all work.
- Hidden posts contribute nothing, and deleting a post corrects the counts.
- No settings, on purpose — hashtags exist because a post says so, and anything configurable would contradict the text that created it.
Installing
composer require ernestdefoe/hashtags
php flarum cache:clear
Flarum 2.0+ and PHP 8.2+. flarum/tags and flarum/mentions are both optional — it works without either and integrates with both.
Already have posts? Flarum stores posts as parsed XML, so a #gameday written before you installed this is sitting in a plain text node and will never become a link on its own. One command fixes that:
php flarum hashtags:reindex --dry-run
php flarum hashtags:reindex
Only posts that actually contain a hashtag are rewritten — everything else is read and skipped — and it's idempotent, so a second run reports 0 updated.
Links
Bug reports and feature requests are welcome in the support tag above.
