prop/lib/microwaveprop_web/controllers/contact_map_controller.ex
Graham McIntire 2e46ceffcc
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Optimize contact map rendering performance
- Switch polylines and circle markers to shared L.canvas() renderer,
  eliminating ~58k SVG DOM nodes in favor of 1 GPU-composited canvas
- Add server-side callsign/date filtering to /api/contacts/map endpoint
  to reduce payload size when filters are active
- Add early-exit fast path in applyCallsignFilter when no filter active
- Batch rebuildDots with requestAnimationFrame to avoid redundant work
  during rapid filter changes
2026-08-02 13:21:15 -05:00

84 lines
2.6 KiB
Elixir

defmodule MicrowavepropWeb.ContactMapController do
@moduledoc """
Serves the contact map JSON payload as a standalone HTTP endpoint. Keeps
the ~5 MB blob out of the `/contacts/map` LiveView's initial HTML response
and lets the browser's native `Content-Encoding: gzip` handling do the
compression. The payload itself is served from `Microwaveprop.Cache` via
`Radio.contact_map_payload/0`.
"""
use MicrowavepropWeb, :controller
alias Microwaveprop.Cache
alias Microwaveprop.Radio
alias MicrowavepropWeb.Api.RateLimiter
plug RateLimiter, anon_limit: 10, auth_limit: 60
@cache_key {__MODULE__, :gzipped_payload}
@cache_ttl_ms 10 * 60 * 1_000
@doc false
@spec cache_key() :: {module(), :gzipped_payload}
def cache_key, do: @cache_key
@spec show(Plug.Conn.t(), map()) :: Plug.Conn.t()
def show(conn, params) do
filters = extract_filters(params)
{body, encoding} = gzipped_or_plain_body(conn, filters)
conn
|> put_resp_content_type("application/json")
|> maybe_put_encoding(encoding)
|> put_resp_header("cache-control", "public, max-age=60")
|> send_resp(200, body)
end
defp extract_filters(params) do
[]
|> maybe_add_filter(:callsign, params["callsign"])
|> maybe_add_filter(:start_date, params["start_date"])
|> maybe_add_filter(:end_date, params["end_date"])
end
defp maybe_add_filter(filters, _key, nil), do: filters
defp maybe_add_filter(filters, _key, ""), do: filters
defp maybe_add_filter(filters, key, value), do: [{key, value} | filters]
defp gzipped_or_plain_body(conn, [] = filters) do
if accepts_gzip?(conn) do
{gzipped_payload(), :gzip}
else
%{json: iodata} = Radio.contact_map_payload(filters)
{IO.iodata_to_binary(iodata), :identity}
end
end
defp gzipped_or_plain_body(conn, filters) do
# Filtered requests vary by parameter — don't cache the gzip blob.
%{json: iodata} = Radio.contact_map_payload(filters)
body = IO.iodata_to_binary(iodata)
if accepts_gzip?(conn) do
{:zlib.gzip(body), :gzip}
else
{body, :identity}
end
end
defp gzipped_payload do
Cache.fetch_or_store(@cache_key, @cache_ttl_ms, fn ->
%{json: iodata} = Radio.contact_map_payload([])
:zlib.gzip(IO.iodata_to_binary(iodata))
end)
end
defp accepts_gzip?(conn) do
case get_req_header(conn, "accept-encoding") do
[value | _] -> String.contains?(value, "gzip")
_ -> false
end
end
defp maybe_put_encoding(conn, :gzip), do: put_resp_header(conn, "content-encoding", "gzip")
defp maybe_put_encoding(conn, :identity), do: conn
end