Fix for [HER-1603?focusedCommentId=22557] browsers based on WebKit (Safari,

iPhone Safari, Chrome) use a screwy 'Accept' header that if taken literally
means they prefer 'application/xml' content. Thus trying to view web UI in
these browsers results in seeing the XML version, without element markup
* BaseResource.java
    override getPreferredVariant() to bump up preference level of text/html for
    any client can accept it
* EngineResource.java, JobResource.java
    inherit from BaseResource

engine/src/main/java/org/archive/crawler/restlet/BaseResource.java

@@ -0,0 +1,56 @@
+/*
+ *  This file is part of the Heritrix web crawler (crawler.archive.org).
+ *
+ *  Licensed to the Internet Archive (IA) by one or more individual 
+ *  contributors. 
+ *
+ *  The IA licenses this file to You under the Apache License, Version 2.0
+ *  (the "License"); you may not use this file except in compliance with
+ *  the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+package org.archive.crawler.restlet;
+
+import org.restlet.Context;
+import org.restlet.data.MediaType;
+import org.restlet.data.Preference;
+import org.restlet.data.Request;
+import org.restlet.data.Response;
+import org.restlet.resource.Resource;
+import org.restlet.resource.Variant;
+
+/**
+ * Abstract {@code Resource} with common shared functionality. 
+ * 
+ * @contributor nlevitt
+ */
+public abstract class BaseResource extends Resource {
+
+    public BaseResource(Context ctx, Request req, Response res) {
+        super(ctx, req, res);
+    }
+
+    /**
+     * If client can accept text/html, always prefer it. WebKit-based browsers
+     * claim to want application/xml, but we don't want to give it to them. See
+     * {@link https://webarchive.jira.com/browse/HER-1603}
+     */
+    public Variant getPreferredVariant() {
+        for (Preference<MediaType> mediaTypePreference: getRequest().getClientInfo().getAcceptedMediaTypes()) {
+            if (mediaTypePreference.getMetadata().equals(MediaType.TEXT_HTML)) {
+                mediaTypePreference.setQuality(Float.MAX_VALUE);
+                break;
+            }
+        }
+        
+        return super.getPreferredVariant();
+    }
+}

engine/src/main/java/org/archive/crawler/restlet/EngineResource.java

@@ -44,7 +44,6 @@ import org.restlet.data.MediaType;
 import org.restlet.data.Request;
 import org.restlet.data.Response;
 import org.restlet.resource.Representation;
-import org.restlet.resource.Resource;
 import org.restlet.resource.ResourceException;
 import org.restlet.resource.Variant;
 import org.restlet.resource.WriterRepresentation;
@@ -56,7 +55,7 @@ import org.xml.sax.SAXException;
  * 
  * @contributor gojomo
  */
-public class EngineResource extends Resource {
+public class EngineResource extends BaseResource {
 
     public EngineResource(Context ctx, Request req, Response res) {
         super(ctx, req, res);

engine/src/main/java/org/archive/crawler/restlet/JobResource.java

@@ -57,7 +57,6 @@ import org.restlet.data.Request;
 import org.restlet.data.Response;
 import org.restlet.data.Status;
 import org.restlet.resource.Representation;
-import org.restlet.resource.Resource;
 import org.restlet.resource.ResourceException;
 import org.restlet.resource.Variant;
 import org.restlet.resource.WriterRepresentation;
@@ -69,7 +68,7 @@ import org.xml.sax.SAXException;
  * 
  * @contributor gojomo
  */
-public class JobResource extends Resource {
+public class JobResource extends BaseResource {
     public static final IOFileFilter EDIT_FILTER = 
         FileUtils.getRegexFileFilter(".*\\.((c?xml)|(txt))$");