extract image proxying from FeedUtils

commafeed-server/src/main/java/com/commafeed/backend/feed/FeedUtils.java

@@ -3,7 +3,6 @@ package com.commafeed.backend.feed;
 import java.util.List;
 
 import org.apache.commons.lang3.StringUtils;
-import org.apache.hc.client5.http.utils.Base64;
 import org.jsoup.Jsoup;
 import org.jsoup.nodes.Document;
 import org.jsoup.nodes.Element;
@@ -69,34 +68,8 @@ public class FeedUtils {
 		if (StringUtils.isBlank(url)) {
 			return url;
 		}
-		return "rest/server/proxy?u=" + imageProxyEncoder(url);
-	}
 
-	public static String rot13(String msg) {
-		StringBuilder message = new StringBuilder();
-
-		for (char c : msg.toCharArray()) {
-			if (c >= 'a' && c <= 'm') {
-				c += 13;
-			} else if (c >= 'n' && c <= 'z') {
-				c -= 13;
-			} else if (c >= 'A' && c <= 'M') {
-				c += 13;
-			} else if (c >= 'N' && c <= 'Z') {
-				c -= 13;
-			}
-			message.append(c);
-		}
-
-		return message.toString();
-	}
-
-	public static String imageProxyEncoder(String url) {
-		return Base64.encodeBase64String(rot13(url).getBytes());
-	}
-
-	public static String imageProxyDecoder(String code) {
-		return rot13(new String(Base64.decodeBase64(code)));
+		return "rest/server/proxy?u=" + ImageProxyUrl.encode(url);
 	}
 
 	public static void removeUnwantedFromSearch(List<Entry> entries, List<FeedEntryKeyword> keywords) {

commafeed-server/src/main/java/com/commafeed/backend/feed/ImageProxyUrl.java

@@ -0,0 +1,37 @@
+package com.commafeed.backend.feed;
+
+import org.apache.hc.client5.http.utils.Base64;
+
+import lombok.experimental.UtilityClass;
+
+@UtilityClass
+public class ImageProxyUrl {
+
+	public static String encode(String url) {
+		return Base64.encodeBase64String(rot13(url).getBytes());
+	}
+
+	public static String decode(String code) {
+		return rot13(new String(Base64.decodeBase64(code)));
+	}
+
+	private static String rot13(String msg) {
+		StringBuilder message = new StringBuilder();
+
+		for (char c : msg.toCharArray()) {
+			if (c >= 'a' && c <= 'm') {
+				c += 13;
+			} else if (c >= 'n' && c <= 'z') {
+				c -= 13;
+			} else if (c >= 'A' && c <= 'M') {
+				c += 13;
+			} else if (c >= 'N' && c <= 'Z') {
+				c -= 13;
+			}
+			message.append(c);
+		}
+
+		return message.toString();
+	}
+
+}

commafeed-server/src/main/java/com/commafeed/frontend/resource/ServerREST.java

@@ -17,7 +17,7 @@ import com.commafeed.CommaFeedConfiguration;
 import com.commafeed.CommaFeedVersion;
 import com.commafeed.backend.HttpGetter;
 import com.commafeed.backend.HttpGetter.HttpResult;
-import com.commafeed.backend.feed.FeedUtils;
+import com.commafeed.backend.feed.ImageProxyUrl;
 import com.commafeed.frontend.model.ServerInfo;
 import com.commafeed.security.Roles;
 
@@ -77,7 +77,7 @@ public class ServerREST {
 			return Response.status(Status.FORBIDDEN).build();
 		}
 
-		url = FeedUtils.imageProxyDecoder(url);
+		url = ImageProxyUrl.decode(url);
 		try {
 			HttpResult result = httpGetter.get(url);
 			return Response.ok(result.getContent()).build();

commafeed-server/src/test/java/com/commafeed/backend/feed/ImageProxyUrlTest.java

@@ -0,0 +1,57 @@
+package com.commafeed.backend.feed;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+class ImageProxyUrlTest {
+
+	@ParameterizedTest
+	@ValueSource(
+			strings = {
+					// simple URL
+					"http://example.com/image.jpg",
+
+					// URL with query parameters
+					"https://example.com/image.png?width=100&height=200",
+
+					// URL with special characters
+					"https://example.com/path/image.gif?param=value&other=test#fragment",
+
+					// URL with non-ascii characters
+					"https://example.com/image-ñáéíóú.jpg",
+
+					// blank URL
+					"",
+
+					// URL with port number
+					"http://localhost:8080/images/photo.jpg",
+
+					// long URL
+					"https://very-long-domain-name-example.com/very/long/path/to/image/file/with/many/segments/image.jpg?param1=value1&param2=value2&param3=value3",
+
+					// URL with mixed case
+					"HTTPS://EXAMPLE.COM/Image.JPG",
+
+					// URL with port number
+					"https://example123.com/image123.jpg?id=456789", })
+	void testEncodingDecoding(String originalUrl) {
+		String encoded = ImageProxyUrl.encode(originalUrl);
+		String decoded = ImageProxyUrl.decode(encoded);
+
+		Assertions.assertEquals(originalUrl, decoded);
+	}
+
+	@Test
+	void encodeProducesDifferentResultForDifferentUrls() {
+		String url1 = "https://example.com/image1.jpg";
+		String url2 = "https://example.com/image2.jpg";
+
+		String encoded1 = ImageProxyUrl.encode(url1);
+		String encoded2 = ImageProxyUrl.encode(url2);
+
+		Assertions.assertNotEquals(encoded1, encoded2);
+	}
+
+}