aprs.me/lib/aprsme_web/plugs/set_locale.ex
Graham McIntire b8a9b8a465
chore(dialyzer): enable stricter flags and fix 97 resulting findings
Turned on :error_handling, :underspecs, and :unmatched_returns in
mix.exs dialyzer config. The 97 warnings this surfaced were fixed in
place rather than suppressed:

- unmatched_return (79): explicit discard with `_ = ...` for
  fire-and-forget side effects (Process.cancel_timer, :ets.new,
  send/2), and pattern-matched `:ok = ...` for control-plane
  Phoenix.PubSub subscribe/unsubscribe/broadcast calls so a future
  return-shape change fails loud.

- contract_supertype (18): tightened @spec arg and return types on
  data_builder, historical_loader, url_params, packet_utils,
  encoding_utils, aprs_symbol, weather_controller, packet_replay to
  match each function's actual success typing.

No behavioural change. mix compile clean, 1008 tests pass, dialyzer
count is now 0.
2026-04-21 10:07:01 -05:00

48 lines
1.2 KiB
Elixir

defmodule AprsmeWeb.Plugs.SetLocale do
@moduledoc """
A plug that sets the locale based on the Accept-Language header.
Falls back to English if the requested locale is not available.
"""
import Plug.Conn
def init(opts), do: opts
def call(conn, _opts) do
locale = get_locale_from_header(conn) || "en"
# Set the backend's locale for the current process
_ = Gettext.put_locale(AprsmeWeb.Gettext, locale)
# Store locale in session for LiveView to access
conn = put_session(conn, :locale, locale)
conn
end
defp get_locale_from_header(conn) do
conn
|> get_req_header("accept-language")
|> extract_locale()
end
defp extract_locale([accept_language | _]), do: parse_accept_language(accept_language)
defp extract_locale(_), do: nil
defp parse_accept_language(accept_language) do
accept_language
|> String.split(",")
|> Enum.map(&parse_language_tag/1)
|> Enum.find(&supported_locale?/1)
end
defp parse_language_tag(tag) do
tag
|> String.trim()
|> String.split(";")
|> List.first()
|> String.split("-")
|> List.first()
|> String.downcase()
end
defp supported_locale?(locale) do
locale in ~w(en es fr de)
end
end