neiam /apollos_crib

It's Apollo's Crib

Stop the offering page loading a whole country every ten seconds

17836dc · Gabriel Morell · 2026-09-07 02:58

11 files +59 -1

Message

{commit_body(@commit)}

modified apps/room_sanctum/lib/room_sanctum/storage.ex

+18 −0

@@ -1057,6 +1057,24 @@ defmodule RoomSanctum.Storage do

1057	1057	\|> Repo.all()
1058	1058	end
1059	1059
	1060	+ @doc """
	1061	+ The first `limit` stops of a source, for callers that cannot use all of them.
	1062	+
	1063	+ A map is the case this exists for. Germany's feed has stops by the hundred
	1064	+ thousand, and drawing them is neither possible nor useful -- but fetching
	1065	+ them is what actually broke: the offering page reloaded every stop on a ten
	1066	+ second timer, which at that size took longer than the fifteen second query
	1067	+ timeout and killed the LiveView on a loop.
	1068	+
	1069	+ Ordered, so the same stops come back each time rather than whatever the
	1070	+ planner felt like -- a map whose markers reshuffle every tick is worse than
	1071	+ one showing a stable subset.
	1072	+ """
	1073	+ def list_stops(source_id, limit) when is_integer(limit) do
	1074	+ from(p in Stop, where: p.source_id == ^source_id, order_by: p.stop_id, limit: ^limit)
	1075	+ \|> Repo.all()
	1076	+ end
	1077	+
1060	1078	def list_stops(source_id, search_term) do
1061	1079	from(p in Stop,
1062	1080	where:

modified apps/room_sanctum/lib/room_sanctum_web/live/cfg_source_live/show.ex

+9 −0

@@ -30,6 +30,10 @@ defmodule RoomSanctumWeb.SourceLive.Show do

30	30	\|> assign(:vehicle_positions, [])
31	31	\|> assign(:free_bikes, [])
32	32	\|> assign(:stations, [])
	33	+ # Set here as well as on the tick: the dead render happens before the
	34	+ # first tick, and a template reading an assign that is not there yet is
	35	+ # a KeyError on the very first paint.
	36	+ \|> assign(:station_count, 0)
33	37	# Both are otherwise only set by the :update_sec tick 200ms in, so any
34	38	# view touching them could be rendered before they exist.
35	39	\|> assign(:station_statuses, [])

@@ -76,6 +80,10 @@ defmodule RoomSanctumWeb.SourceLive.Show do

76	80
77	81	stations = Stations.for_source(socket.assigns.source)
78	82
	83	+ # What the map is not showing. Counted rather than inferred from the list,
	84	+ # which cannot tell a source with exactly the cap from one with far more.
	85	+ station_count = Stations.count_for_source(socket.assigns.source)
	86	+
79	87	# Add station status for GBFS sources
80	88	station_statuses = Stations.statuses_for_source(socket.assigns.source)
81	89

@@ -104,6 +112,7 @@ defmodule RoomSanctumWeb.SourceLive.Show do

104	112	\|> assign(:available_tints, available_tints)
105	113	\|> assign(:free_bikes, free_bikes)
106	114	\|> assign(:stations, stations)
	115	+ \|> assign(:station_count, station_count)
107	116	\|> assign(:station_statuses, station_statuses)
108	117	\|> assign(:route_types, route_types)
109	118	\|> assign(:aircraft, aircraft)

modified apps/room_sanctum/lib/room_sanctum_web/live/cfg_source_live/show.html.heex

+6 −0

@@ -491,6 +491,12 @@ gl_available_projects={@gitlab_available_projects}

491	491	add_query_event="map-add-query"
492	492	queried_station_ids={Enum.map(@queries, &station_id_of/1)}
493	493	/>
	494	+ <%!-- A national feed has stops by the hundred thousand.
	495	+ The map draws a bounded subset; saying so is better
	496	+ than a map that looks complete and is not. --%>
	497	+ <p :if={@station_count > length(@stations)} class="text-xs opacity-60 mt-1">
	498	+ Showing <%= length(@stations) %> of <%= @station_count %> stops.
	499	+ </p>
494	500	</div>
495	501
496	502	<% @view_mode == :paint -> %>

modified apps/room_sanctum/lib/room_sanctum_web/live/cfg_source_live/stations.ex

+26 −1

@@ -25,6 +25,31 @@ defmodule RoomSanctumWeb.SourceLive.Stations do

25	25
26	26	@mappable [:gtfs, :gbfs, :aqi]
27	27
	28	+ # How many stops one source may contribute to a map.
	29	+ #
	30	+ # A national feed has hundreds of thousands, and no map draws that -- but the
	31	+ # cost that mattered was fetching them: the offering page reloads its
	32	+ # stations on a ten second timer, and for Germany that query outran the
	33	+ # fifteen second timeout and took the LiveView down with it, every tick.
	34	+ #
	35	+ # Two thousand is well past what is legible on a map and small enough that
	36	+ # the query is never the slow part. `count_for_source/1` says how many there
	37	+ # really are, so a capped map can admit to it rather than quietly lying about
	38	+ # the size of the feed.
	39	+ @map_cap 2000
	40	+
	41	+ @doc "The cap `for_source/1` applies to a single source's stops."
	42	+ def map_cap, do: @map_cap
	43	+
	44	+ @doc """
	45	+ How many places a source actually has, capped or not.
	46	+
	47	+ Counted in the database rather than by measuring what came back, which
	48	+ cannot tell a source with exactly the cap from one with far more.
	49	+ """
	50	+ def count_for_source(%{type: :gtfs, id: id}), do: Storage.count_stops(id)
	51	+ def count_for_source(source), do: source \|> for_source() \|> length()
	52	+
28	53	@doc "Whether a source has geography of its own to draw."
29	54	def mappable?(%{type: type}), do: type in @mappable
30	55	def mappable?(_), do: false

@@ -40,7 +65,7 @@ defmodule RoomSanctumWeb.SourceLive.Stations do

40	65	def for_source(%{type: :gbfs, id: id}), do: Storage.list_gbfs_station_information(id)
41	66
42	67	def for_source(%{type: :gtfs, id: id}),
43		− do: id \|> Storage.list_stops() \|> Enum.map(&stop_as_station/1)
	68	+ do: id \|> Storage.list_stops(@map_cap) \|> Enum.map(&stop_as_station/1)
44	69
45	70	def for_source(%{type: :aqi, id: id}),
46	71	do: id \|> Storage.list_aqi_stations() \|> Enum.map(&site_as_station/1)

Parents: f7912e4