feat: Added gzip content handling for features requests (#329)

* feat: Added gzip content handling for features requests

fixes #328

* Update src/main/java/io/getunleash/repository/HttpFeatureFetcher.java

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* fix(nit): Removed unnecessary comments

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: chriswk

pom.xml

@@ -115,20 +115,20 @@
         <dependency>
             <groupId>org.assertj</groupId>
             <artifactId>assertj-core</artifactId>
-            <version>3.26.3</version>
+            <version>3.27.6</version>
             <scope>test</scope>
         </dependency>
 
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-core</artifactId>
-            <version>4.8.1</version>
+            <version>5.20.0</version>
             <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>com.github.tomakehurst</groupId>
             <artifactId>wiremock-jre8</artifactId>
-            <version>2.35.2</version>
+            <version>3.0.1</version>
             <scope>test</scope>
         </dependency>
         <dependency>
@@ -177,6 +177,13 @@
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-dependency-plugin</artifactId>
                 <version>3.8.1</version>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>properties</goal>
+                        </goals>
+                    </execution>
+                </executions>
             </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
@@ -219,7 +226,7 @@
             <plugin>
                 <groupId>org.jacoco</groupId>
                 <artifactId>jacoco-maven-plugin</artifactId>
-                <version>0.8.12</version>
+                <version>0.8.13</version>
                 <executions>
                     <execution>
                         <id>prepare-agent</id>
@@ -410,6 +417,9 @@
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-surefire-plugin</artifactId>
                 <version>3.5.2</version>
+                <configuration>
+                    <argLine>@{argLine} -javaagent:${org.mockito:mockito-core:jar}</argLine>
+                </configuration>
             </plugin>
         </plugins>
     </reporting>

src/main/java/io/getunleash/repository/HttpFeatureFetcher.java

@@ -5,15 +5,13 @@
 import io.getunleash.UnleashException;
 import io.getunleash.event.ClientFeaturesResponse;
 import io.getunleash.util.UnleashConfig;
-import java.io.BufferedReader;
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.InputStreamReader;
+import java.io.*;
 import java.net.HttpURLConnection;
 import java.net.URL;
 import java.nio.charset.StandardCharsets;
 import java.util.Optional;
 import java.util.stream.Collectors;
+import java.util.zip.GZIPInputStream;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -59,15 +57,30 @@ private ClientFeaturesResponse getFeatureResponse(
 
         if (responseCode < 300) {
             etag = Optional.ofNullable(request.getHeaderField("ETag"));
-
-            try (BufferedReader reader =
-                    new BufferedReader(
-                            new InputStreamReader(
-                                    (InputStream) request.getContent(), StandardCharsets.UTF_8))) {
-
-                String clientFeatures = reader.lines().collect(Collectors.joining("\n"));
-
-                return ClientFeaturesResponse.updated(clientFeatures);
+            String contentEncoding = request.getHeaderField("Content-Encoding");
+            if ("gzip".equalsIgnoreCase(contentEncoding)) {
+                try (GZIPInputStream stream = new GZIPInputStream(request.getInputStream())) {
+                    try (ByteArrayOutputStream outputStream = new ByteArrayOutputStream()) {
+                        byte[] buffer = new byte[1024];
+                        int len;
+                        while ((len = stream.read(buffer)) != -1) {
+                            outputStream.write(buffer, 0, len);
+                        }
+                        String clientFeatures = outputStream.toString(StandardCharsets.UTF_8);
+                        return ClientFeaturesResponse.updated(clientFeatures);
+                    }
+                }
+            } else {
+                try (BufferedReader reader =
+                        new BufferedReader(
+                                new InputStreamReader(
+                                        (InputStream) request.getContent(),
+                                        StandardCharsets.UTF_8))) {
+
+                    String clientFeatures = reader.lines().collect(Collectors.joining("\n"));
+
+                    return ClientFeaturesResponse.updated(clientFeatures);
+                }
             }
         } else if (followRedirect
                 && (responseCode == HttpURLConnection.HTTP_MOVED_TEMP
@@ -114,6 +127,7 @@ private HttpURLConnection openConnection(URL url) throws IOException {
         connection.setReadTimeout((int) this.config.getFetchTogglesReadTimeout().toMillis());
         connection.setRequestProperty("Accept", "application/json");
         connection.setRequestProperty("Content-Type", "application/json");
+        connection.setRequestProperty("Accept-Encoding", "gzip,deflate");
         UnleashConfig.setRequestProperties(connection, this.config);
 
         etag.ifPresent(val -> connection.setRequestProperty("If-None-Match", val));

src/test/java/io/getunleash/HotReloadSchedulerReuseTest.java

@@ -1,25 +1,23 @@
 package io.getunleash;
 
-import io.getunleash.util.UnleashConfig;
-import org.junit.jupiter.api.*;
+import static org.assertj.core.api.Assertions.assertThat;
 
+import io.getunleash.util.UnleashConfig;
 import java.lang.reflect.Field;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
-
-import static org.assertj.core.api.Assertions.assertThat;
+import org.junit.jupiter.api.*;
 
 class HotReloadSchedulerReuseTest {
 
-
     private UnleashConfig baseConfig() {
         return UnleashConfig.builder()
-            .appName("hot-reload-test-app")
-            .instanceId("A")
-            .unleashAPI("http://localhost")    // never hit
-            .synchronousFetchOnInitialisation(false)
-            .fetchTogglesInterval(100)
-            .sendMetricsInterval(100)
-            .build();
+                .appName("hot-reload-test-app")
+                .instanceId("A")
+                .unleashAPI("http://localhost") // never hit
+                .synchronousFetchOnInitialisation(false)
+                .fetchTogglesInterval(100)
+                .sendMetricsInterval(100)
+                .build();
     }
 
     private ScheduledThreadPoolExecutor currentGlobalExecutor() throws Exception {
@@ -37,9 +35,7 @@ private ScheduledThreadPoolExecutor currentGlobalExecutor() throws Exception {
     @Test
     void secondClientDoesNotReuseSchedulerExecutor() throws Exception {
         // 1) Create first client; let it schedule background tasks
-        DefaultUnleash first = new DefaultUnleash(
-            baseConfig()
-        );
+        DefaultUnleash first = new DefaultUnleash(baseConfig());
 
         // Let it initialize/schedule
         Thread.sleep(150);
@@ -57,11 +53,10 @@ void secondClientDoesNotReuseSchedulerExecutor() throws Exception {
         assertThat(execAfterShutdown).isNull();
 
         // 3) "Reloaded app": create a second client in the same JVM (statics still around)
-        DefaultUnleash second = new DefaultUnleash(
-            baseConfig()
-        );
+        DefaultUnleash second = new DefaultUnleash(baseConfig());
 
-        // 4) Assert that the second client creates a fresh executor (not reusing the terminated one)
+        // 4) Assert that the second client creates a fresh executor (not reusing the terminated
+        // one)
         ScheduledThreadPoolExecutor execUsedBySecond = currentGlobalExecutor();
         assertThat(execUsedBySecond).isNotNull();
         assertThat(execUsedBySecond.isShutdown()).isFalse(); // it's a new one