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