Redirect /Documentation(/)? to /Documentation/index.html

Bug: Issue 9974
Change-Id: Idf415661d82ab171101b2da036c29f2cd336da87
diff --git a/java/com/google/gerrit/httpd/UrlModule.java b/java/com/google/gerrit/httpd/UrlModule.java
index 6620c44..183b2bd 100644
--- a/java/com/google/gerrit/httpd/UrlModule.java
+++ b/java/com/google/gerrit/httpd/UrlModule.java
@@ -110,7 +110,9 @@
     serveRegex("^/(?:a/)?groups/(.*)?$").with(GroupsRestApiServlet.class);
     serveRegex("^/(?:a/)?projects/(.*)?$").with(ProjectsRestApiServlet.class);
 
-    filter("/Documentation/").through(QueryDocumentationFilter.class);
+    serveRegex("^/Documentation$").with(redirectDocumentation());
+    serveRegex("^/Documentation/$").with(redirectDocumentation());
+    filter("/Documentation/*").through(QueryDocumentationFilter.class);
   }
 
   private Key<HttpServlet> notFound() {
@@ -235,6 +237,19 @@
         });
   }
 
+  private Key<HttpServlet> redirectDocumentation() {
+    return key(
+        new HttpServlet() {
+          private static final long serialVersionUID = 1L;
+
+          @Override
+          protected void doGet(HttpServletRequest req, HttpServletResponse rsp) throws IOException {
+            String path = "/Documentation/index.html";
+            toGerrit(path, req, rsp);
+          }
+        });
+  }
+
   static void toGerrit(String target, HttpServletRequest req, HttpServletResponse rsp)
       throws IOException {
     final StringBuilder url = new StringBuilder();
diff --git a/java/com/google/gerrit/httpd/raw/StaticModule.java b/java/com/google/gerrit/httpd/raw/StaticModule.java
index 664d881..124ad1c 100644
--- a/java/com/google/gerrit/httpd/raw/StaticModule.java
+++ b/java/com/google/gerrit/httpd/raw/StaticModule.java
@@ -119,6 +119,8 @@
 
   @Override
   protected void configureServlets() {
+    serveRegex("^/Documentation$").with(named(DOC_SERVLET));
+    serveRegex("^/Documentation/$").with(named(DOC_SERVLET));
     serveRegex("^/Documentation/(.+)$").with(named(DOC_SERVLET));
     serve("/static/*").with(SiteStaticDirectoryServlet.class);
     install(