Finished first draft of methods to do with querying channels

ideas.md

@@ -1,3 +1,3 @@
 - Write media datbase ID as metadata/to file/whatever so it gives us an option to retroactively match media to the DB down the line. Useful if someone moves the media without informing the UI
-   - Use a UUID for the media database ID (or at least alongside it)
+  - Use a UUID for the media database ID (or at least alongside it)
 - Look into this and its recommended plugins https://hexdocs.pm/ex_check/readme.html

lib/pinchflat/downloader/backends/yt_dlp/channel.ex

@@ -3,27 +3,26 @@ defmodule Pinchflat.Downloader.Backends.YtDlp.Channel do
   Contains utilities for working with a channel's videos
   """
 
-  # TODO: convert to `use`
-  import Pinchflat.Downloader.Backends.YtDlp.VideoCollection
-  alias __MODULE__
+  use Pinchflat.Downloader.Backends.YtDlp.VideoCollection
+  alias Pinchflat.Downloader.ChannelDetails
 
-  defstruct [:id, :name]
+  @doc """
+  Gets a channel's ID and name from its URL.
 
-  def new(id, name) do
-    %__MODULE__{id: id, name: name}
-  end
+  yt-dlp does not _really_ have channel-specific functions, so
+  instead we're fetching just the first video (using playlist_end: 1)
+  and parsing the channel ID and name from _its_ metadata
 
+  Returns {:ok, %ChannelDetails{}} | {:error, any, ...}.
+  """
   def get_channel_info(channel_url) do
     opts = [print: "%(.{channel,channel_id})j", playlist_end: 1]
 
-    case backend_runner().run(channel_url, opts) do
-      {:ok, output} ->
-        result = Phoenix.json_library().decode!(output)
-
-        {:ok, Channel.new(result["channel_id"], result["channel"])}
-
-      res ->
-        res
+    with {:ok, output} <- backend_runner().run(channel_url, opts),
+         {:ok, parsed_json} <- Phoenix.json_library().decode(output) do
+      {:ok, ChannelDetails.new(parsed_json["channel_id"], parsed_json["channel"])}
+    else
+      err -> err
     end
   end
 

lib/pinchflat/downloader/backends/yt_dlp/command_runner.ex

@@ -11,6 +11,8 @@ defmodule Pinchflat.Downloader.Backends.YtDlp.CommandRunner do
   @doc """
   Runs a yt-dlp command and returns the string output
 
+  Returns {:ok, binary()} | {:error, output, status}.
+
   # IDEA: deduplicate command opts, keeping the last one on conflict
           although possibly not needed (and a LOT easier) if yt-dlp
           just ignores duplicate options (ie: look into that)

lib/pinchflat/downloader/backends/yt_dlp/video.ex

@@ -6,13 +6,16 @@ defmodule Pinchflat.Downloader.Backends.YtDlp.Video do
   @doc """
   Downloads a single video (and possible metadata) directly to its
   final destination. Returns the parsed JSON output from yt-dlp.
+
+  Returns {:ok, map()} | {:error, any, ...}.
   """
   def download(url, command_opts \\ []) do
     opts = [:no_simulate, print: "%()j"] ++ command_opts
 
-    case backend_runner().run(url, opts) do
-      # TODO: test that I changed this to a ! method
-      {:ok, output} -> {:ok, Phoenix.json_library().decode!(output)}
+    with {:ok, output} <- backend_runner().run(url, opts),
+         {:ok, parsed_json} <- Phoenix.json_library().decode(output) do
+      {:ok, parsed_json}
+    else
       err -> err
     end
   end

lib/pinchflat/downloader/backends/yt_dlp/video_collection.ex

@@ -2,22 +2,27 @@ defmodule Pinchflat.Downloader.Backends.YtDlp.VideoCollection do
   @moduledoc """
   Contains utilities for working with collections of videos (ie: channels, playlists).
 
-  Meant to be included in other modules but can be used on its own.
+  Meant to be included in other modules but can be used on its own. Channels and playlists
+  will have many of their own methods, but also share a lot of methods. This module is for
+  those shared methods.
   """
 
-  @doc """
-  Returns a list of strings representing the video ids in the collection
-  """
-  def get_video_ids(url, command_opts \\ []) do
-    opts = command_opts ++ [:simulate, :skip_download, print: :id]
+  defmacro __using__(_) do
+    quote do
+      @doc """
+      Returns a list of strings representing the video ids in the collection.
 
-    case backend_runner().run(url, opts) do
-      {:ok, output} -> {:ok, String.split(output, "\n", trim: true)}
-      res -> res
+      Returns {:ok, [binary()]} | {:error, any, ...}.
+      """
+      def get_video_ids(url, command_opts \\ []) do
+        runner = Application.get_env(:pinchflat, :yt_dlp_runner)
+        opts = command_opts ++ [:simulate, :skip_download, print: :id]
+
+        case runner.run(url, opts) do
+          {:ok, output} -> {:ok, String.split(output, "\n", trim: true)}
+          res -> res
+        end
+      end
     end
   end
-
-  defp backend_runner do
-    Application.get_env(:pinchflat, :yt_dlp_runner)
-  end
 end

lib/pinchflat/downloader/channel_details.ex

@@ -0,0 +1,32 @@
+defmodule Pinchflat.Downloader.ChannelDetails do
+  @moduledoc """
+  This is the integration layer for actually working with channels.
+
+  Technically hardcodes the yt-dlp backend for now, but should leave
+  it open-ish for future expansion (just in case).
+  """
+  @enforce_keys [:id, :name]
+  defstruct [:id, :name]
+
+  alias Pinchflat.Downloader.Backends.YtDlp.Channel, as: YtDlpChannel
+
+  @doc false
+  def new(id, name) do
+    %__MODULE__{id: id, name: name}
+  end
+
+  @doc """
+  Gets a channel's ID and name from its URL, using the given backend.
+
+  Returns {:ok, map()} | {:error, any, ...}.
+  """
+  def get_channel_details(channel_url, backend \\ :yt_dlp) do
+    channel_module(backend).get_channel_info(channel_url)
+  end
+
+  defp channel_module(backend) do
+    case backend do
+      :yt_dlp -> YtDlpChannel
+    end
+  end
+end

lib/pinchflat/downloader/video_downloader.ex

@@ -15,6 +15,8 @@ defmodule Pinchflat.Downloader.VideoDownloader do
 
   @doc """
   Downloads a single video based on the settings in the given media profile.
+
+  Returns {:ok, %ChannelDetails{}} | {:error, any, ...}.
   """
   def download_for_media_profile(url, %MediaProfile{} = media_profile, backend \\ :yt_dlp) do
     option_builder = option_builder(backend)

test/pinchflat/downloader/backends/yt_dlp/channel_test.exs

@@ -0,0 +1,44 @@
+defmodule Pinchflat.Downloader.Backends.YtDlp.ChannelTest do
+  use ExUnit.Case, async: true
+  import Mox
+
+  alias Pinchflat.Downloader.ChannelDetails
+  alias Pinchflat.Downloader.Backends.YtDlp.Channel
+
+  @channel_url "https://www.youtube.com/c/TheUselessTrials"
+
+  setup :verify_on_exit!
+
+  describe "get_channel_info/1" do
+    test "it returns a %ChannelDetails{} with data on success" do
+      expect(CommandRunnerMock, :run, fn _url, _opts ->
+        {:ok, "{\"channel\": \"TheUselessTrials\", \"channel_id\": \"UCQH2\"}"}
+      end)
+
+      assert {:ok, res} = Channel.get_channel_info(@channel_url)
+      assert %ChannelDetails{id: "UCQH2", name: "TheUselessTrials"} = res
+    end
+
+    test "it passes the expected args to the backend runner" do
+      expect(CommandRunnerMock, :run, fn @channel_url, opts ->
+        assert opts == [{:print, "%(.{channel,channel_id})j"}, {:playlist_end, 1}]
+
+        {:ok, "{}"}
+      end)
+
+      assert {:ok, _} = Channel.get_channel_info(@channel_url)
+    end
+
+    test "it returns an error if the runner returns an error" do
+      expect(CommandRunnerMock, :run, fn _url, _opts -> {:error, "Big issue", 1} end)
+
+      assert {:error, "Big issue", 1} = Channel.get_channel_info(@channel_url)
+    end
+
+    test "it returns an error if the output is not JSON" do
+      expect(CommandRunnerMock, :run, fn _url, _opts -> {:ok, "Not JSON"} end)
+
+      assert {:error, %Jason.DecodeError{}} = Channel.get_channel_info(@channel_url)
+    end
+  end
+end

test/pinchflat/downloader/backends/yt_dlp/video_collection_test.exs

@@ -6,13 +6,17 @@ defmodule Pinchflat.Downloader.Backends.YtDlp.VideoCollectionTest do
 
   @channel_url "https://www.youtube.com/@TheUselessTrials"
 
+  defmodule VideoCollectionUser do
+    use VideoCollection
+  end
+
   setup :verify_on_exit!
 
   describe "get_video_ids/2" do
     test "returns a list of video ids with no blank elements" do
       expect(CommandRunnerMock, :run, fn _url, _opts -> {:ok, "id1\nid2\n\nid3\n"} end)
 
-      assert {:ok, ["id1", "id2", "id3"]} = VideoCollection.get_video_ids(@channel_url)
+      assert {:ok, ["id1", "id2", "id3"]} = VideoCollectionUser.get_video_ids(@channel_url)
     end
 
     test "it passes the expected default args" do
@@ -22,7 +26,7 @@ defmodule Pinchflat.Downloader.Backends.YtDlp.VideoCollectionTest do
         {:ok, ""}
       end)
 
-      assert {:ok, _} = VideoCollection.get_video_ids(@channel_url)
+      assert {:ok, _} = VideoCollectionUser.get_video_ids(@channel_url)
     end
 
     test "it passes the expected custom args" do
@@ -32,13 +36,13 @@ defmodule Pinchflat.Downloader.Backends.YtDlp.VideoCollectionTest do
         {:ok, ""}
       end)
 
-      assert {:ok, _} = VideoCollection.get_video_ids(@channel_url, [:custom_arg])
+      assert {:ok, _} = VideoCollectionUser.get_video_ids(@channel_url, [:custom_arg])
     end
 
     test "returns the error straight through when the command fails" do
       expect(CommandRunnerMock, :run, fn _url, _opts -> {:error, "Big issue", 1} end)
 
-      assert {:error, "Big issue", 1} = VideoCollection.get_video_ids(@channel_url)
+      assert {:error, "Big issue", 1} = VideoCollectionUser.get_video_ids(@channel_url)
     end
   end
 end

test/pinchflat/downloader/backends/yt_dlp/video_test.exs

@@ -35,6 +35,12 @@ defmodule Pinchflat.Downloader.Backends.YtDlp.VideoTest do
       assert {:ok, %{"title" => "Test"}} = Video.download(@video_url)
     end
 
+    test "it returns an error if the output is not JSON" do
+      expect(CommandRunnerMock, :run, fn _url, _opts -> {:ok, "Not JSON"} end)
+
+      assert {:error, %Jason.DecodeError{}} = Video.download(@video_url)
+    end
+
     test "it directly passes along any errors" do
       expect(CommandRunnerMock, :run, fn _url, _opts -> {:error, "Big issue", 1} end)
 

test/pinchflat/downloader/channel_details_test.exs

@@ -0,0 +1,38 @@
+defmodule Pinchflat.Downloader.ChannelDetailsTest do
+  use ExUnit.Case, async: true
+  import Mox
+
+  alias Pinchflat.Downloader.ChannelDetails
+
+  @channel_url "https://www.youtube.com/c/TheUselessTrials"
+
+  setup :verify_on_exit!
+
+  describe "new/2" do
+    test "it returns a struct with the given values" do
+      assert %ChannelDetails{id: "UCQH2", name: "TheUselessTrials"} =
+               ChannelDetails.new("UCQH2", "TheUselessTrials")
+    end
+  end
+
+  describe "get_channel_details/2" do
+    test "it passes the expected arguments to the backend" do
+      expect(CommandRunnerMock, :run, fn @channel_url, opts ->
+        assert opts == [{:print, "%(.{channel,channel_id})j"}, {:playlist_end, 1}]
+
+        {:ok, "{\"channel\": \"TheUselessTrials\", \"channel_id\": \"UCQH2\"}"}
+      end)
+
+      assert {:ok, _} = ChannelDetails.get_channel_details(@channel_url)
+    end
+
+    test "it returns a struct composed of the returned data" do
+      expect(CommandRunnerMock, :run, fn _url, _opts ->
+        {:ok, "{\"channel\": \"TheUselessTrials\", \"channel_id\": \"UCQH2\"}"}
+      end)
+
+      assert {:ok, res} = ChannelDetails.get_channel_details(@channel_url)
+      assert %ChannelDetails{id: "UCQH2", name: "TheUselessTrials"} = res
+    end
+  end
+end