Merge pull request #5 from Thoroldvix/feat/playlist-transcripts

Add bulk retrieval of transcripts for playlists and channels

Author: trldvix

README.md

@@ -12,7 +12,8 @@
 ## 📖 Introduction
 
 Java library which allows you to retrieve subtitles/transcripts for a YouTube video.
-It supports manual and automatically generated subtitles and does not use headless browser for scraping.
+It supports manual and automatically generated subtitles, bulk transcript retrieval for all videos in the playlist or
+on the channel and does not use headless browser for scraping.
 Inspired by [Python library](https://github.com/jdepoix/youtube-transcript-api).
 
 ## 🤖 Features
@@ -21,6 +22,8 @@ Inspired by [Python library](https://github.com/jdepoix/youtube-transcript-api).
 
 ✅ Automatically generated transcripts retrieval
 
+✅ Bulk transcript retrieval for all videos in the playlist or channel
+
 ✅ Transcript translation
 
 ✅ Transcript formatting
@@ -79,7 +82,7 @@ TranscriptList transcriptList = youtubeTranscriptApi.listTranscripts("videoId");
 
 // Iterate over transcript list
 for(Transcript transcript : transcriptList) {
-    System.out.println(transcript);
+        System.out.println(transcript);
 }
 
 // Find transcript in specific language
@@ -143,6 +146,8 @@ TranscriptContent transcriptContent = youtubeTranscriptApi.listTranscripts("vide
 TranscriptContent transcriptContent = youtubeTranscriptApi.getTranscript("videoId");
 ```
 
+For bulk transcript retrieval see [Bulk Transcript Retrieval](#bulk-transcript-retrieval).
+
 ## 🔧 Detailed Usage
 
 ### Use fallback language
@@ -241,7 +246,7 @@ TranscriptFormatter jsonFormatter = TranscriptFormatters.jsonFormatter();
 String formattedContent = jsonFormatter.format(transcriptContent);
 ````
 
-### YoutubeClient customization
+### YoutubeClient Customization
 
 By default, `YoutubeTranscriptApi` uses Java 11 HttpClient for making requests to YouTube, if you want to use a
 different client,
@@ -275,6 +280,52 @@ TranscriptList transcriptList = youtubeTranscriptApi.listTranscriptsWithCookies(
 TranscriptContent transcriptContent = youtubeTranscriptApi.getTranscriptWithCookies("videoId", "path/to/cookies.txt", "en");
 ```
 
+### Bulk Transcript Retrieval
+
+All bulk transcript retrieval operations are done via the `PlaylistsTranscriptApi` interface. Same as with the
+`YoutubeTranscriptApi`,
+you can create a new instance of the PlaylistsTranscriptApi by calling the `createDefaultPlaylistsApi` method of the
+`TranscriptApiFactory`.
+Playlists and channels information is retrieved from
+the [YouTube V3 API](https://developers.google.com/youtube/v3/docs/),
+so you will need to provide API key for all methods.
+
+```java
+// Create a new default PlaylistsTranscriptApi instance
+PlaylistsTranscriptApi playlistsTranscriptApi = TranscriptApiFactory.createDefaultPlaylistsApi();
+
+// Retrieve all available transcripts for a given playlist
+Map<String, TranscriptList> transcriptLists = playlistsTranscriptApi.listTranscriptsForPlaylist("playlistId", "apiKey", true);
+
+// Retrieve all available transcripts for a given channel
+Map<String, TranscriptList> transcriptLists = playlistsTranscriptApi.listTranscriptsForChannel("channelName", "apiKey", true);
+```
+
+As you can see, there is also a boolean flag `continueOnError`, which tells whether to continue if transcript retrieval
+fails for a video or not. For example, if it's set to `true`, all transcripts that could not be retrieved will be
+skipped, if
+it's set to `false`, operation will fail fast on the first error.
+
+All methods are also have overloaded versions which accept path to [cookies.txt](#cookies) file.
+
+```java
+// Retrieve all available transcripts for a given playlist
+Map<String, TranscriptList> transcriptLists = playlistsTranscriptApi.listTranscriptsForPlaylist(
+        "playlistId",
+        "apiKey",
+        true,
+        "path/to/cookies.txt"
+);
+
+// Retrieve all available transcripts for a given channel
+Map<String, TranscriptList> transcriptLists = playlistsTranscriptApi.listTranscriptsForChannel(
+        "channelName",
+        "apiKey",
+        true,
+        "path/to/cookies.txt"
+);
+```
+
 ## 🤓 How it works
 
 Within each YouTube video page, there exists JSON data containing all the transcript information, including an

lib/src/main/java/io/github/thoroldvix/api/PlaylistsTranscriptApi.java

@@ -0,0 +1,71 @@
+package io.github.thoroldvix.api;
+
+import io.github.thoroldvix.internal.TranscriptApiFactory;
+
+import java.util.Map;
+
+/**
+ * Retrieves transcripts for all videos in a playlist, or all videos for a specific channel.
+ * <p>
+ * Playlists and channel videos are retrieved from the YouTube API, so you will need to have a valid api key to use this.
+ * </p>
+ * <p>
+ * To get implementation for this interface see {@link TranscriptApiFactory}
+ * </p>
+ */
+public interface PlaylistsTranscriptApi {
+
+    /**
+     * Retrieves transcript lists for all videos in the specified playlist using provided API key and cookies file from a specified path.
+     *
+     * @param playlistId      The ID of the playlist
+     * @param apiKey          API key for the YouTube V3 API (see <a href="https://developers.google.com/youtube/v3/getting-started">Getting started</a>)
+     * @param continueOnError Whether to continue if transcript retrieval fails for a video. If true, all transcripts that could not be retrieved will be skipped,
+     *                        otherwise an exception will be thrown.
+     * @param cookiesPath     The file path to the text file containing the authentication cookies. Used in the case if some videos are age restricted see {<a href="https://github.com/Thoroldvix/youtube-transcript-api#cookies">Cookies</a>}
+     * @return A map of video IDs to {@link TranscriptList} objects
+     * @throws TranscriptRetrievalException If the retrieval of the transcript lists fails
+     */
+    Map<String, TranscriptList> listTranscriptsForPlaylist(String playlistId, String apiKey, String cookiesPath, boolean continueOnError) throws TranscriptRetrievalException;
+
+
+    /**
+     * Retrieves transcript lists for all videos in the specified playlist using provided API key.
+     *
+     * @param playlistId      The ID of the playlist
+     * @param apiKey          API key for the YouTube V3 API (see <a href="https://developers.google.com/youtube/v3/getting-started">Getting started</a>)
+     * @param continueOnError Whether to continue if transcript retrieval fails for a video. If true, all transcripts that could not be retrieved will be skipped,
+     *                        otherwise an exception will be thrown.
+     * @return A map of video IDs to {@link TranscriptList} objects
+     * @throws TranscriptRetrievalException If the retrieval of the transcript lists fails
+     */
+    Map<String, TranscriptList> listTranscriptsForPlaylist(String playlistId, String apiKey, boolean continueOnError) throws TranscriptRetrievalException;
+
+
+    /**
+     * Retrieves transcript lists for all videos for the specified channel using provided API key and cookies file from a specified path.
+     *
+     * @param channelName     The name of the channel
+     * @param apiKey          API key for the YouTube V3 API (see <a href="https://developers.google.com/youtube/v3/getting-started">Getting started</a>)
+     * @param cookiesPath     The file path to the text file containing the authentication cookies. Used in the case if some videos are age restricted see {<a href="https://github.com/Thoroldvix/youtube-transcript-api#cookies">Cookies</a>}
+     * @param continueOnError Whether to continue if transcript retrieval fails for a video. If true, all transcripts that could not be retrieved will be skipped,
+     *                        otherwise an exception will be thrown.
+     * @return A map of video IDs to {@link TranscriptList} objects
+     * @throws TranscriptRetrievalException If the retrieval of the transcript lists fails
+     * @throws TranscriptRetrievalException If the retrieval of the transcript lists fails
+     */
+    Map<String, TranscriptList> listTranscriptsForChannel(String channelName, String apiKey, String cookiesPath, boolean continueOnError) throws TranscriptRetrievalException;
+
+
+    /**
+     * Retrieves transcript lists for all videos for the specified channel using provided API key.
+     *
+     * @param channelName     The name of the channel
+     * @param apiKey          API key for the YouTube V3 API (see <a href="https://developers.google.com/youtube/v3/getting-started">Getting started</a>)
+     * @param continueOnError Whether to continue if transcript retrieval fails for a video. If true, all transcripts that could not be retrieved will be skipped,
+     *                        otherwise an exception will be thrown.
+     * @return A map of video IDs to {@link TranscriptList} objects
+     * @throws TranscriptRetrievalException If the retrieval of the transcript lists fails
+     */
+    Map<String, TranscriptList> listTranscriptsForChannel(String channelName, String apiKey, boolean continueOnError) throws TranscriptRetrievalException;
+}

lib/src/main/java/io/github/thoroldvix/api/TranscriptList.java

@@ -56,6 +56,13 @@ public interface TranscriptList extends Iterable<Transcript> {
      */
     Transcript findManualTranscript(String... languageCodes) throws TranscriptRetrievalException;
 
+    /**
+     * Retrieves the ID of the video to which transcript was retrieved.
+     *
+     * @return The video ID.
+     */
+    String getVideoId();
+
     @Override
     default void forEach(Consumer<? super Transcript> action) {
         Iterable.super.forEach(action);

lib/src/main/java/io/github/thoroldvix/api/TranscriptRetrievalException.java

@@ -10,7 +10,7 @@ public class TranscriptRetrievalException extends Exception {
 
     private static final String ERROR_MESSAGE = "Could not retrieve transcript for the video: %s.\nReason: %s";
     private static final String YOUTUBE_WATCH_URL = "https://www.youtube.com/watch?v=";
-    private final String videoId;
+    private String videoId;
 
     /**
      * Constructs a new exception with the specified detail message and cause.
@@ -36,10 +36,22 @@ public TranscriptRetrievalException(String videoId, String message) {
     }
 
     /**
-     * @return The ID of the video for which the transcript retrieval failed.
+     * Constructs a new exception with the specified detail message and cause.
+     *
+     * @param message The detail message explaining the reason for the failure.
+     * @param cause   The cause of the failure (which is saved for later retrieval by the {@link Throwable#getCause()} method).
      */
-    public String getVideoId() {
-        return videoId;
+    public TranscriptRetrievalException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    /**
+     * Constructs a new exception with the specified detail message.
+     *
+     * @param message The detail message explaining the reason for the failure.
+     */
+    public TranscriptRetrievalException(String message) {
+        super(message);
     }
 
     /**
@@ -53,5 +65,12 @@ private static String buildErrorMessage(String videoId, String message) {
         String videoUrl = YOUTUBE_WATCH_URL + videoId;
         return String.format(ERROR_MESSAGE, videoUrl, message);
     }
+
+    /**
+     * @return The ID of the video for which the transcript retrieval failed.
+     */
+    public String getVideoId() {
+        return videoId;
+    }
 }
 

lib/src/main/java/io/github/thoroldvix/api/YoutubeClient.java

@@ -6,7 +6,6 @@
 /**
  * Responsible for sending GET requests to YouTube.
  */
-@FunctionalInterface
 public interface YoutubeClient {
 
     /**
@@ -18,5 +17,16 @@ public interface YoutubeClient {
      * @throws TranscriptRetrievalException If the request to YouTube fails.
      */
     String get(String url, Map<String, String> headers) throws TranscriptRetrievalException;
+
+
+    /**
+     * Sends a GET request to the specified endpoint and returns the response body.
+     *
+     * @param endpoint The endpoint to which the GET request is made.
+     * @param params   A map of parameters to include in the request.
+     * @return The body of the response as a {@link String}.
+     * @throws TranscriptRetrievalException If the request to YouTube fails.
+     */
+    String get(YtApiV3Endpoint endpoint, Map<String, String> params) throws TranscriptRetrievalException;
 }
 

lib/src/main/java/io/github/thoroldvix/api/YtApiV3Endpoint.java

@@ -0,0 +1,28 @@
+package io.github.thoroldvix.api;
+
+/**
+ * The YouTube API V3 endpoints. Used by the {@link YoutubeClient}.
+ */
+public enum YtApiV3Endpoint {
+    PLAYLIST_ITEMS("playlistItems"),
+    SEARCH("search"),
+    CHANNELS("channels");
+    private final static String YOUTUBE_API_V3_BASE_URL = "https://www.googleapis.com/youtube/v3/";
+
+    private final String resource;
+    private final String url;
+
+    YtApiV3Endpoint(String resource) {
+        this.url = YOUTUBE_API_V3_BASE_URL + resource;
+        this.resource = resource;
+    }
+
+    public String url() {
+        return url;
+    }
+
+    @Override
+    public String toString() {
+        return resource;
+    }
+}