allow changing of context path with a http header

scm-plugins/scm-svn-plugin/src/main/java/sonia/scm/web/SvnDAVServlet.java

@@ -45,8 +45,8 @@ import org.tmatesoft.svn.core.internal.server.dav.DAVConfig;
 import org.tmatesoft.svn.core.internal.server.dav.DAVServlet;
 
 import sonia.scm.repository.Repository;
-import sonia.scm.repository.RepositoryRequestListenerUtil;
 import sonia.scm.repository.RepositoryProvider;
+import sonia.scm.repository.RepositoryRequestListenerUtil;
 import sonia.scm.repository.SvnRepositoryHandler;
 import sonia.scm.util.AssertUtil;
 import sonia.scm.util.HttpUtil;
@@ -68,6 +68,9 @@ import javax.servlet.http.HttpServletResponse;
 public class SvnDAVServlet extends DAVServlet
 {
 
+  /** Field description */
+  private static final String HEADER_CONTEXTPATH = "X-Forwarded-Ctx";
+
   /** Field description */
   private static final long serialVersionUID = -1462257085465785945L;
 
@@ -86,8 +89,7 @@ public class SvnDAVServlet extends DAVServlet
    * @param repositoryRequestListenerUtil
    */
   @Inject
-  public SvnDAVServlet(
+  public SvnDAVServlet(SvnRepositoryHandler handler,
-          SvnRepositoryHandler handler,
     RepositoryProvider repositoryProvider,
     RepositoryRequestListenerUtil repositoryRequestListenerUtil)
   {
@@ -177,6 +179,25 @@ public class SvnDAVServlet extends DAVServlet
 
     //~--- get methods --------------------------------------------------------
 
+    /**
+     * Method description
+     *
+     *
+     * @return
+     */
+    @Override
+    public String getContextPath()
+    {
+      String header = getHeader(HEADER_CONTEXTPATH);
+
+      if ((header == null) ||!isValidContextPath(header))
+      {
+        header = super.getContextPath();
+      }
+
+      return header;
+    }
+
     /**
      * Method description
      *
@@ -230,6 +251,32 @@ public class SvnDAVServlet extends DAVServlet
       return servletPath;
     }
 
+    /**
+     * Method description
+     *
+     *
+     * @param ctx
+     *
+     * @return
+     */
+    private boolean isValidContextPath(String ctx)
+    {
+      int length = ctx.length();
+
+      boolean result = (length == 0)
+                       || ((length > 1)
+                         && ctx.startsWith(HttpUtil.SEPARATOR_PATH));
+
+      if (!result)
+      {
+        logger.warn(
+          "header {} contains a non valid context path, fallback to default",
+          HEADER_CONTEXTPATH);
+      }
+
+      return result;
+    }
+
     //~--- fields -------------------------------------------------------------
 
     /** Field description */