rewrite favicon fetcher

src/main/java/com/commafeed/backend/favicon/YoutubeFaviconFetcher.java

@@ -0,0 +1,87 @@
+package com.commafeed.backend.favicon;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+
+import org.jsoup.Jsoup;
+import org.jsoup.nodes.Document;
+import org.jsoup.select.Elements;
+
+import com.commafeed.backend.HttpGetter;
+import com.commafeed.backend.HttpGetter.HttpResult;
+
+@Slf4j
+@RequiredArgsConstructor(onConstructor = @__({ @Inject }))
+@Singleton
+public class YoutubeFaviconFetcher extends AbstractFaviconFetcher {
+
+	private final HttpGetter getter;
+
+	@Override
+	public byte[] fetch(String url) {
+		if (!url.toLowerCase().contains("://gdata.youtube.com/")) {
+			return null;
+		}
+
+		String userName = extractUserName(url);
+		if (userName == null) {
+			return null;
+		}
+
+		String profileUrl = "https://gdata.youtube.com/feeds/users/" + userName;
+
+		byte[] bytes = null;
+		String contentType = null;
+
+		try {
+			log.debug("Getting YouTube user's icon, {}", url);
+
+			// initial get to translate username to obscure user thumbnail URL
+			HttpResult profileResult = getter.getBinary(profileUrl, TIMEOUT);
+			Document doc = Jsoup.parse(new String(profileResult.getContent()), profileUrl);
+
+			Elements thumbnails = doc.select("media|thumbnail");
+			if (thumbnails.isEmpty()) {
+				return null;
+			}
+
+			String thumbnailUrl = thumbnails.get(0).attr("abs:url");
+
+			int thumbnailStart = thumbnailUrl.indexOf("<media:thumbnail url='");
+			int thumbnailEnd = thumbnailUrl.indexOf("'/>", thumbnailStart);
+			if (thumbnailStart != -1) {
+				thumbnailUrl = thumbnailUrl.substring(thumbnailStart + "<media:thumbnail url='".length(), thumbnailEnd);
+			}
+
+			// final get to actually retrieve the thumbnail
+			HttpResult iconResult = getter.getBinary(thumbnailUrl, TIMEOUT);
+			bytes = iconResult.getContent();
+			contentType = iconResult.getContentType();
+		} catch (Exception e) {
+			log.debug("Failed to retrieve YouTube icon", e);
+		}
+
+		if (!isValidIconResponse(bytes, contentType)) {
+			bytes = null;
+		}
+		return bytes;
+	}
+
+	private String extractUserName(String url) {
+		int apiOrBase = url.indexOf("/users/");
+		if (apiOrBase == -1) {
+			return null;
+		}
+
+		int userEndSlash = url.indexOf('/', apiOrBase + "/users/".length());
+		if (userEndSlash == -1) {
+			return null;
+		}
+
+		return url.substring(apiOrBase + "/users/".length(), userEndSlash);
+	}
+
+}