Adding basic support for favicon

src/main/java/com/commafeed/frontend/rest/resources/FeedREST.java

@@ -1,7 +1,9 @@
 package com.commafeed.frontend.rest.resources;
 
 import java.io.StringWriter;
+import java.io.UnsupportedEncodingException;
 import java.net.URI;
+import java.net.URLDecoder;
 import java.util.Calendar;
 import java.util.Collections;
 import java.util.Comparator;
@@ -17,8 +19,10 @@ import javax.ws.rs.PathParam;
 import javax.ws.rs.Produces;
 import javax.ws.rs.QueryParam;
 import javax.ws.rs.WebApplicationException;
+import javax.ws.rs.core.CacheControl;
 import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.Response;
+import javax.ws.rs.core.Response.ResponseBuilder;
 import javax.ws.rs.core.Response.Status;
 
 import org.apache.commons.fileupload.FileItem;
@@ -48,6 +52,7 @@ import com.commafeed.frontend.model.request.IDRequest;
 import com.commafeed.frontend.model.request.MarkRequest;
 import com.commafeed.frontend.model.request.SubscribeRequest;
 import com.commafeed.frontend.rest.Enums.ReadType;
+import com.commafeed.frontend.utils.FetchFavicon;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.Lists;
 import com.sun.syndication.feed.opml.Opml;
@@ -245,6 +250,30 @@ public class FeedREST extends AbstractResourceREST {
 						.getPublicUrl(), 0)).build();
 	}
 
+	@GET
+	@Path("/favicon")
+	@ApiOperation(value = "Fetch feed icon", notes = "Fetch icon of a feed")
+	public Response favicon(@QueryParam("url") String path) {
+		try {
+			path = URLDecoder.decode(path, "UTF-8");
+		} catch (UnsupportedEncodingException e) {
+			e.printStackTrace();
+		}
+		byte[] icon = new FetchFavicon().get(path);
+		ResponseBuilder reponse = Response.ok(icon, "image/x-icon");
+
+		CacheControl cacheControl = new CacheControl();
+		cacheControl.setMaxAge(2592000);
+		cacheControl.setPrivate(false);
+		reponse.cacheControl(cacheControl); // trying to replicate "public, max-age=2592000"
+
+		Calendar calendar = Calendar.getInstance();
+		calendar.add(Calendar.MONTH, 1);
+		reponse.expires(calendar.getTime());
+
+		return reponse.build();
+	}
+
 	@POST
 	@Path("/subscribe")
 	@ApiOperation(value = "Subscribe to a feed", notes = "Subscribe to a feed")

src/main/java/com/commafeed/frontend/utils/FetchFavicon.java

@@ -0,0 +1,150 @@
+package com.commafeed.frontend.utils;
+
+import java.net.MalformedURLException;
+import java.net.URL;
+
+import org.jsoup.Connection.Response;
+import org.jsoup.Jsoup;
+import org.jsoup.nodes.Document;
+import org.jsoup.select.Elements;
+
+//Inspired/Ported from https://github.com/potatolondon/getfavicon
+public class FetchFavicon {
+	void inf(String message) {
+		//
+	}
+
+	static long MIN_ICON_LENGTH = 100;
+	static long MAX_ICON_LENGTH = 20000;
+	static String[] ICON_MIMETYPES = new String[] { "image/x-icon",
+			"image/vnd.microsoft.icon", "image/ico", "image/icon", "text/ico",
+			"application/ico", "image/x-ms-bmp", "image/x-bmp", "image/gif",
+			"image/png", "image/jpeg" };
+
+	static String[] ICON_MIMETYPE_BLACKLIST = new String[] { "application/xml",
+			"text/html" };
+
+	boolean in(String[] array, String value) {
+		for (String i : array) {
+			if (i.equals(value)) {
+				return true;
+			}
+		}
+		return false;
+	}
+
+	boolean isValidIconResponse(Response iconResponse) {
+		long iconLength = iconResponse.bodyAsBytes().length;
+
+		String iconContentType = iconResponse.header("Content-Type");
+		if (!iconContentType.isEmpty())
+			iconContentType = iconContentType.split(";")[0];
+
+		if (iconResponse.statusCode() != 200) {
+			inf("Status code isn't 200");
+			return false;
+		}
+
+		if (in(ICON_MIMETYPE_BLACKLIST, iconContentType)) {
+			inf("Content-Type in ICON_MIMETYPE_BLACKLIST");
+			return false;
+		}
+
+		if (iconLength < MIN_ICON_LENGTH) {
+			inf("Length below MIN_ICON_LENGTH");
+			return false;
+		}
+
+		if (iconLength > MAX_ICON_LENGTH) {
+			inf("Length greater than MAX_ICON_LENGTH");
+			return false;
+		}
+		return true;
+	}
+
+	byte[] iconAtRoot(String targetPath) {
+		Response rootIconPath;
+		try {
+			URL url = new URL(new URL(targetPath), "/favicon.ico");
+			inf(url.toString());
+			rootIconPath = Jsoup
+					.connect(url.toString())
+					.followRedirects(true)
+					.ignoreContentType(true).execute();
+		} catch (Exception e) {
+			inf("Failed to retrieve iconAtRoot");
+			return null;
+		}
+
+		if (isValidIconResponse(rootIconPath)) {
+			return rootIconPath.bodyAsBytes();
+		}
+		return null;
+	}
+
+	byte[] iconInPage(String targetPath) {
+		inf("iconInPage, trying " + targetPath);
+
+		Document pageSoup;
+		try {
+			pageSoup = Jsoup.connect(targetPath).followRedirects(true).get();
+		} catch (Exception e) {
+			inf("Failed to retrieve page to find icon");
+			return null;
+		}
+
+		Elements pageSoupIcon = pageSoup
+				.select("link[rel~=(?i)^(shortcut|icon|shortcut icon)$]");
+
+		if (pageSoupIcon.size() == 0) {
+			return null;
+		}
+		String pageIconHref = pageSoupIcon.get(0).attr("href");
+		String pageIconPath;
+		if (pageIconHref.isEmpty()) {
+			inf("No icon found in page");
+			return null;
+		}
+
+		try {
+			pageIconPath = new URL(new URL(targetPath), pageIconHref).toString();
+		} catch (MalformedURLException e1) {
+			inf("URL concatination faild");
+			return null;
+		}
+
+		inf("Found unconfirmed iconInPage at");
+
+		Response pagePathFaviconResult;
+		try {
+			pagePathFaviconResult = Jsoup.connect(pageIconPath)
+					.followRedirects(true).ignoreContentType(true)
+					.execute();
+		} catch (Exception e) {
+			inf("Failed to retrieve icon found in page");
+			return null;
+		}
+
+		if (isValidIconResponse(pagePathFaviconResult)) {
+			return pagePathFaviconResult.bodyAsBytes();
+		}
+		inf("Invalid icon found");
+		return null;
+	}
+
+	public byte[] get(String targetPath) {
+		byte[] icon;
+
+		icon = iconAtRoot(targetPath);
+		if (icon != null) {
+			return icon;
+		}
+
+		icon = iconInPage(targetPath);
+		if (icon != null) {
+			return icon;
+		}
+
+		return null; // or returning default feed
+	}
+}