feat: Add GZIP support to DefaultAPIMiddleware

Issue #13 (closed)

core/src/main/java/org/eclipsefoundation/core/service/impl/DefaultAPIMiddleware.java

+/* Copyright (c) 2019 Eclipse Foundation and others.
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Public License 2.0
+ * which is available at http://www.eclipse.org/legal/epl-v20.html,
+ * 
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package org.eclipsefoundation.core.service.impl;
 
 import java.io.InputStream;
@@ -7,6 +14,7 @@ import java.util.List;
 import java.util.function.Function;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
+import java.util.zip.GZIPInputStream;
 
 import javax.enterprise.context.ApplicationScoped;
 import javax.inject.Inject;
@@ -25,11 +33,13 @@ import com.fasterxml.jackson.databind.ObjectMapper;
 import io.quarkus.arc.Unremovable;
 
 /**
- * Serves as a middleware for external calls. This generalizes retrieving multiple pages of data using the Link header
- * rather than manually iterating over the data or using less robust checks (such as no data in response), or for
+ * Serves as a middleware for external calls. This generalizes retrieving
+ * multiple pages of data using the Link header
+ * rather than manually iterating over the data or using less robust checks
+ * (such as no data in response), or for
  * passing that pagination data on to the current request.
  * 
- * @author Martin Lowe
+ * @author Martin Lowe, Zachary Sabourin
  *
  */
 @ApplicationScoped
@@ -85,7 +95,9 @@ public class DefaultAPIMiddleware implements APIMiddleware {
     private <T> List<T> readInValue(List<T> out, Response r, Class<T> type) {
         Object o = r.getEntity();
         try {
-            if (o instanceof InputStream) {
+            if (o instanceof InputStream && r.getHeaderString("Content-Encoding").equalsIgnoreCase("GZIP")) {
+                out.addAll(objectMapper.readerForListOf(type).readValue(new GZIPInputStream((InputStream) o)));
+            } else if (o instanceof InputStream) {
                 out.addAll(objectMapper.readerForListOf(type).readValue((InputStream) o));
             } else if (type.isAssignableFrom(o.getClass())) {
                 out.add((T) o);