diff --git a/contrib/src/main/java/org/archive/modules/extractor/KnowledgableExtractorJS.java b/contrib/src/main/java/org/archive/modules/extractor/KnowledgableExtractorJS.java
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+++ b/contrib/src/main/java/org/archive/modules/extractor/KnowledgableExtractorJS.java
@@ -0,0 +1,115 @@
+/*
+ *  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.modules.extractor;
+
+import java.util.Collection;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import java.util.regex.Matcher;
+
+import org.apache.commons.httpclient.URIException;
+import org.apache.commons.lang.StringEscapeUtils;
+import org.apache.commons.lang.exception.NestableRuntimeException;
+import org.archive.modules.CrawlURI;
+import org.archive.net.UURI;
+import org.archive.net.UURIFactory;
+import org.archive.util.TextUtils;
+
+/**
+ * A subclass of {@link ExtractorJS} that has some customized behavior for
+ * specific kinds of web pages. As of April 2015, the one special behavior it
+ * has is for drupal generated pages. See https://webarchive.jira.com/browse/ARI-4190
+ */
+public class KnowledgableExtractorJS extends ExtractorJS {
+
+    private static Logger LOGGER = 
+            Logger.getLogger(KnowledgableExtractorJS.class.getName());
+
+    /**
+     * Wraps a {@link CrawlURI}, allowing baseURI to be overridden, without
+     * changing the underlying CrawlURI. The only methods implemented are the
+     * ones necessary for {@link ExtractorJS} to work properly.
+     */
+    protected static class CustomizedCrawlURIFacade extends CrawlURI {
+        private static final long serialVersionUID = 1l;
+
+        protected CrawlURI wrapped;
+        protected UURI baseURI;
+
+        public CustomizedCrawlURIFacade(CrawlURI wrapped, UURI baseURI) {
+            super(wrapped.getUURI(), wrapped.getPathFromSeed(), wrapped.getVia(), wrapped.getViaContext());
+            this.wrapped = wrapped;
+            this.baseURI = baseURI;
+        }
+
+        /**
+         * @return value set in {@link #KnowledgableExtractorJS(CrawlURI, UURI)}
+         */
+        @Override
+        public UURI getBaseURI() {
+            return baseURI;
+        }
+
+        /** Delegates to wrapped CrawlURI */
+        @Override
+        public CrawlURI createCrawlURI(UURI destination, LinkContext context,
+                Hop hop) throws URIException {
+            return wrapped.createCrawlURI(destination, context, hop);
+        }
+
+        /** Delegates to wrapped CrawlURI */
+        @Override
+        public Collection<CrawlURI> getOutLinks() {
+            return wrapped.getOutLinks();
+        }
+
+        /** Delegates to wrapped CrawlURI */
+        @Override
+        public void incrementDiscardedOutLinks() {
+            wrapped.incrementDiscardedOutLinks();
+        }
+    }
+
+    public long considerStrings(Extractor ext, 
+            CrawlURI curi, CharSequence cs, boolean handlingJSFile) {
+
+        CrawlURI baseUri = curi;
+
+        Matcher m = TextUtils.getMatcher("jQuery\\.extend\\(Drupal\\.settings,[^'\"]*['\"]basePath['\"]:[^'\"]*['\"]([^'\"]+)['\"]", cs);
+        if (m.find()) {
+            String basePath = m.group(1);
+            try {
+                basePath = StringEscapeUtils.unescapeJavaScript(basePath);
+            } catch (NestableRuntimeException e) {
+                LOGGER.log(Level.WARNING, "problem unescaping purported drupal basePath '" + basePath + "'", e);
+            }
+
+            try {
+                UURI baseUURI =  UURIFactory.getInstance(curi.getUURI(), basePath);
+                baseUri = new CustomizedCrawlURIFacade(curi, baseUURI);
+            } catch (URIException e) {
+                LOGGER.log(Level.WARNING, "problem creating UURI from drupal basePath '" + basePath + "'", e);
+            }
+        }
+        TextUtils.recycleMatcher(m);
+
+        return super.considerStrings(ext, baseUri, cs, handlingJSFile);
+    }
+
+}