discord-music-bot/app/src/main/java/musicbot/YoutubeSearch.java

package musicbot;
import com.google.api.client.googleapis.json.GoogleJsonResponseException;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.http.HttpRequest;
import com.google.api.client.http.HttpRequestInitializer;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.jackson2.JacksonFactory;
import com.google.api.services.youtube.YouTube;
import com.google.api.services.youtube.model.SearchListResponse;
import com.google.api.services.youtube.model.SearchResult;
import com.google.common.collect.ImmutableList;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import java.util.Optional;
import java.util.Properties;

public class YoutubeSearch {
    private static final String PROPERTIES_FILENAME = "youtube.properties";

    private static final HttpTransport HTTP_TRANSPORT = new NetHttpTransport();

    private static final JsonFactory JSON_FACTORY = new JacksonFactory();

    private static final long NUMBER_VIDEOS_RETURNED = 1;

    private static Properties _properties;

    private static YouTube _youtube;

    public String searchForMusic(final String title, final String artist) {
        _youtube = get_youtube();

        final List<SearchResult> searchResults = doSearch(title, artist);

        final Optional<SearchResult> maybeResult = searchResults.stream().findFirst();
        searchResults.stream().forEach(result -> {
            System.out.println("result ID = " + result.getId());
        });

        return maybeResult.map(result -> "http://www.youtube.com/watch?v=" + result.getId().getVideoId())
                .orElse("No videos found.");
    }

    private YouTube get_youtube() {
        return new YouTube.Builder(
                HTTP_TRANSPORT,
                JSON_FACTORY,
               createRequestInitializer()
        ).setApplicationName("youtube-cmdline-search-sample").build();
    }

    private HttpRequestInitializer createRequestInitializer() {
        final HttpRequestInitializer initializer = new HttpRequestInitializer() {
            public void initialize(HttpRequest request) throws IOException {}
        };

        return initializer;
    }

    private List<SearchResult> doSearch(final String title, final String artist) {
        try {
            final String apiKey = Token.YOUTUBE_API_KEY;

            final String query = title + " by " + artist;

            final YouTube.Search.List search = _youtube.search().list("id,snippet")
                    .setKey(apiKey)
                    .setType("video")
                    .setFields("items(id/kind,id/videoId,snippet/title,snippet/thumbnails/default/url)")
                    .setMaxResults(NUMBER_VIDEOS_RETURNED)
                    .setQ(query);

            final SearchListResponse response = search.execute();
            return response.getItems();
        } catch (GoogleJsonResponseException e) {
            System.err.println("There was a service error: " + e.getDetails().getCode() + " : "
                    + e.getDetails().getMessage());
            return ImmutableList.of();
        } catch (IOException e) {
            System.err.println("There was an IO error: " + e.getCause() + " : " + e.getMessage());
            return ImmutableList.of();
        } catch (Throwable t) {
            t.printStackTrace();
            return ImmutableList.of();
        }
    }
}