Dashboard Filters in the Page URL

Context

ADR 003 kept a dashboard’s filter state in the Stimulus controller and in each Turbo Frame’s src, and named the cost: a reload lost every filter, and a filtered dashboard could not be shared as a link. ADR 005 gave each pane a URL that carries its filters, which made a single pane shareable but not the dashboard around it.

The host application’s page URL is the natural home. It is what a browser bookmarks, what a person pastes into a message, and what Rails already parses into params[:q] on the way in.

Decision

The page URL carries the dashboard’s filters as q[...], the same Ransack parameters every pane already accepts.

/reports/orders?q[customer_region_eq]=APAC&q[status_eq]=paid

The server renders the initial state. janela_dashboard reads params[:q] from the page request and sets it as the controller’s starting filters; janela_pane bakes the same filters into each frame’s initial src. A dashboard opened from a shared link is therefore correct before any JavaScript runs, and the controller’s first pass over the frames changes nothing, so nothing loads twice.

The controller keeps the URL current. Whenever filters change it rewrites the page URL’s q[...] parameters with history.replaceState, preserving whatever else is in the query string and Turbo’s own history state. Filter keys are written in sorted order on both sides so the server and the browser serialise identically.

Replace, not push. Every click does not become a history entry. The back button leaves the dashboard, as it does in every BI tool; undoing a filter is clicking it again or clearing. Pushing each toggle would trap the user in their own click history.

Consequences

• A reload keeps the filters. A pasted dashboard URL opens filtered. Issue #1 is closed.
• A pane URL and a dashboard URL now share the same q vocabulary, so a filter copied from one works in the other. That is the payoff of ADR 002 making Ransack parameters the contract rather than a Janela vocabulary.
• The host page’s other query parameters survive untouched. Janela only owns the q namespace on that URL, which a host using Ransack for a search form on the same page would also want. Documented: put a dashboard and a Ransack search form on different pages, or expect them to share filters.
• Two dashboards on one page would share one URL and one q. Not supported and not a goal; one dashboard per page is the shape.