Handle multiple headers with the same name

Pushes the fixes in dropwizard/dropwizard#8008
upstream into logback-access, where they probably should be.

Unfortunately `HttpGetUtil` uses `HttpURLConnection`, which makes it
hard to write a test for this because `HttpURLConnection` combines the
headers for you.

Signed-off-by: Robert Elliot <[email protected]>

Author: Mahoney

logback-access-jetty12/src/main/java/ch/qos/logback/access/jetty/HeaderUtil.java

@@ -0,0 +1,27 @@
+package ch.qos.logback.access.jetty;
+
+import org.eclipse.jetty.http.HttpField;
+import org.eclipse.jetty.http.HttpFields;
+
+import java.util.Map;
+import java.util.TreeMap;
+
+class HeaderUtil {
+    static Map<String, String> buildHeaderMap(HttpFields headers) {
+        Map<String, String> requestHeaderMap = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
+        for (HttpField f : headers) {
+            String existing = requestHeaderMap.get(f.getName());
+            String value = combine(existing, f.getValue());
+            requestHeaderMap.put(f.getName(), value);
+        }
+        return requestHeaderMap;
+    }
+
+    private static String combine(String existing, String field) {
+        if (existing == null) {
+            return field;
+        } else {
+            return existing + "," + field;
+        }
+    }
+}

logback-access-jetty12/src/main/java/ch/qos/logback/access/jetty/JettyServerAdapter.java

@@ -14,16 +14,13 @@
 package ch.qos.logback.access.jetty;
 
 import ch.qos.logback.access.common.spi.ServerAdapter;
-
-import org.eclipse.jetty.http.HttpField;
-import org.eclipse.jetty.http.HttpFields;
 import org.eclipse.jetty.server.Request;
 import org.eclipse.jetty.server.Response;
 
-import java.util.Enumeration;
-import java.util.HashMap;
 import java.util.Map;
 
+import static ch.qos.logback.access.jetty.HeaderUtil.buildHeaderMap;
+
 /**
  * A jetty specific implementation of the {@link ServerAdapter} interface.
  *
@@ -57,16 +54,7 @@ public long getRequestTimestamp() {
 
     @Override
     public Map<String, String> buildResponseHeaderMap() {
-        Map<String, String> responseHeaderMap = new HashMap<String, String>();
-        HttpFields.Mutable httpFields = response.getHeaders();
-
-        for(HttpField field: httpFields) {
-            String key = field.getName();
-            String value = field.getValue();
-            responseHeaderMap.put(key, value);
-        }
-
-        return responseHeaderMap;
+        return buildHeaderMap(response.getHeaders());
     }
 
 }

logback-access-jetty12/src/main/java/ch/qos/logback/access/jetty/RequestWrapper.java

@@ -17,9 +17,7 @@
 import jakarta.servlet.http.HttpUpgradeHandler;
 import jakarta.servlet.http.Part;
 import org.eclipse.jetty.http.HttpCookie;
-import org.eclipse.jetty.http.HttpField;
 import org.eclipse.jetty.http.HttpScheme;
-import org.eclipse.jetty.http.HttpURI;
 import org.eclipse.jetty.http.HttpVersion;
 import org.eclipse.jetty.server.Request;
 import org.eclipse.jetty.server.Session;
@@ -37,10 +35,10 @@
 import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
-import java.util.TreeMap;
 import java.util.stream.Collectors;
 
 import static ch.qos.logback.access.common.spi.IAccessEvent.NA;
+import static ch.qos.logback.access.jetty.HeaderUtil.buildHeaderMap;
 import static java.nio.charset.StandardCharsets.UTF_8;
 
 public class RequestWrapper implements HttpServletRequest, WrappedHttpRequest {
@@ -92,11 +90,7 @@ public Enumeration<String> getHeaderNames() {
 
     @Override
     public Map<String, String> buildRequestHeaderMap() {
-        Map<String, String> requestHeaderMap = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
-        for (HttpField f : request.getHeaders()) {
-            requestHeaderMap.put(f.getName(), f.getValue());
-        }
-        return requestHeaderMap;
+        return buildHeaderMap(request.getHeaders());
     }
 
     @Override