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- defmodule PodcastFeed.Boundary.ArchiveServer do
- @moduledoc false
- use GenServer, restart: :temporary
- require Logger
- alias PodcastFeed
- alias PodcastFeed.Provider.Archive
- @registry :podcast_registry
- @archive_supervisor :archive_supervisor
- ##########
- ### API
- def start_link(identifier) do
- GenServer.start_link(__MODULE__, identifier, name: via(identifier))
- end
- def cache_or_fetch(identifier) do
- case DynamicSupervisor.start_child(@archive_supervisor, {__MODULE__, identifier}) do
- {:ok, pid} -> {:ok, pid}
- {:error, {:already_started, pid}} -> {:ok, pid}
- error -> error
- end
- # %{id: Worker, start: { Worker, :start_link, [child_name]}, restart: :transient})
- end
- def get_feed(identifier) do
- cache_or_fetch(identifier)
- GenServer.call(via(identifier), :get_feed)
- end
- def reload(identifier) do
- GenServer.call(via(identifier), :reload)
- end
- ##########
- ### SERVER
- def init(identifier) do
- {:ok, %{identifier: identifier, feed_data: fetch_feed_data(identifier)}}
- end
- def handle_call(:get_feed, _from, feed) do
- Logger.debug "retrieve cached feed data for #{feed[:identifier]}..."
- {:reply, feed[:feed_data], feed, Application.fetch_env!(:podcast_feed, :cache_duration)}
- end
- def handle_call(:reload, _from, feed) do
- Logger.debug "discard cached feed data for #{feed[:identifier]}..."
- feed_data = fetch_feed_data(feed[:identifier])
- {:reply, feed_data, %{feed | feed_data: feed_data}}
- end
- def handle_info(:timeout, %{identifier: identifier}) do
- Logger.debug "shutting down #{identifier}..."
- {:stop, :normal, []}
- end
- ##########
- ### PRIVATES
- defp fetch_feed_data(identifier) do
- Logger.debug "fetching archive metadata for #{identifier}..."
- Archive.Parser.by_identifier(identifier)
- end
- defp via(identifier) do
- {:via, Registry, {@registry, identifier}}
- end
- end
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