Add support for extracting videoId from clipId.

src/main/java/me/kavin/piped/ServerLauncher.java

@@ -82,6 +82,13 @@ public class ServerLauncher extends MultithreadedHttpServerLauncher {
                     } catch (Exception e) {
                         return getErrorResponse(e, request.getPath());
                     }
+                })).map(GET, "/clips/:clipId", AsyncServlet.ofBlocking(executor, request -> {
+                    try {
+                        return getJsonResponse(ResponseHelper.resolveClipId(request.getPathParameter("clipId")),
+                                "public, max-age=31536000, immutable");
+                    } catch (Exception e) {
+                        return getErrorResponse(e, request.getPath());
+                    }
                 })).map(GET, "/channel/:channelId", AsyncServlet.ofBlocking(executor, request -> {
                     try {
                         return getJsonResponse(

src/main/java/me/kavin/piped/utils/ResponseHelper.java

@@ -4,6 +4,8 @@ import com.fasterxml.jackson.core.JsonProcessingException;
 import com.github.benmanes.caffeine.cache.Caffeine;
 import com.github.benmanes.caffeine.cache.LoadingCache;
 import com.github.benmanes.caffeine.cache.Scheduler;
+import com.grack.nanojson.JsonObject;
+import com.grack.nanojson.JsonWriter;
 import com.rometools.rome.feed.synd.*;
 import com.rometools.rome.io.FeedException;
 import com.rometools.rome.io.SyndFeedOutput;
@@ -41,6 +43,7 @@ import org.schabi.newpipe.extractor.search.SearchInfo;
 import org.schabi.newpipe.extractor.stream.StreamInfo;
 import org.schabi.newpipe.extractor.stream.StreamInfoItem;
 import org.schabi.newpipe.extractor.stream.StreamType;
+import org.schabi.newpipe.extractor.utils.JsonUtils;
 import org.springframework.security.crypto.argon2.Argon2PasswordEncoder;
 import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
 
@@ -48,14 +51,18 @@ import javax.persistence.criteria.CriteriaBuilder;
 import javax.persistence.criteria.CriteriaQuery;
 import javax.persistence.criteria.Root;
 import java.io.IOException;
-import java.nio.charset.StandardCharsets;
 import java.util.*;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
 import static me.kavin.piped.consts.Constants.YOUTUBE_SERVICE;
 import static me.kavin.piped.utils.URLUtils.rewriteURL;
 import static me.kavin.piped.utils.URLUtils.substringYouTube;
+import static org.schabi.newpipe.extractor.NewPipe.getPreferredContentCountry;
+import static org.schabi.newpipe.extractor.NewPipe.getPreferredLocalization;
+import static org.schabi.newpipe.extractor.services.youtube.YoutubeParsingHelper.getJsonPostResponse;
+import static org.schabi.newpipe.extractor.services.youtube.YoutubeParsingHelper.prepareDesktopJsonBuilder;
 
 public class ResponseHelper {
 
@@ -162,6 +169,22 @@ public class ResponseHelper {
 
     }
 
+    public static byte[] resolveClipId(String clipId) throws Exception {
+
+        final byte[] body = JsonWriter.string(prepareDesktopJsonBuilder(
+                        getPreferredLocalization(), getPreferredContentCountry())
+                        .value("url", "https://www.youtube.com/clip/" + clipId)
+                        .done())
+                .getBytes(UTF_8);
+
+        final JsonObject jsonResponse = getJsonPostResponse("navigation/resolve_url",
+                body, getPreferredLocalization());
+
+        final String videoId = JsonUtils.getString(jsonResponse, "endpoint.watchEndpoint.videoId");
+
+        return Constants.mapper.writeValueAsBytes(new VideoResolvedResponse(videoId));
+    }
+
     public static byte[] channelResponse(String channelPath) throws Exception {
 
         final ChannelInfo info = ChannelInfo.getInfo("https://youtube.com/" + channelPath);
@@ -336,7 +359,7 @@ public class ResponseHelper {
 
         feed.setEntries(entries);
 
-        return new SyndFeedOutput().outputString(feed).getBytes(StandardCharsets.UTF_8);
+        return new SyndFeedOutput().outputString(feed).getBytes(UTF_8);
 
     }
 
@@ -789,7 +812,7 @@ public class ResponseHelper {
 
             s.close();
 
-            return new SyndFeedOutput().outputString(feed).getBytes(StandardCharsets.UTF_8);
+            return new SyndFeedOutput().outputString(feed).getBytes(UTF_8);
         }
 
         s.close();

src/main/java/me/kavin/piped/utils/resp/VideoResolvedResponse.java

@@ -0,0 +1,10 @@
+package me.kavin.piped.utils.resp;
+
+public class VideoResolvedResponse {
+
+    public String videoId;
+
+    public VideoResolvedResponse(String videoId) {
+        this.videoId = videoId;
+    }
+}