Support additional context paths

api/src/org/labkey/api/ApiModule.java

@@ -109,6 +109,7 @@
 import org.labkey.api.view.JspTemplate;
 import org.labkey.api.view.LabKeyKaptchaServlet;
 import org.labkey.api.view.Portal;
+import org.labkey.api.view.RedirectorServlet;
 import org.labkey.api.view.ViewServlet;
 import org.labkey.api.view.WebPartFactory;
 import org.labkey.api.webdav.WebdavResolverImpl;
@@ -197,6 +198,14 @@ public void registerServlets(ServletContext servletCtx)
         // http://host/labkey/filecontent/proj/dir/sendFile.view?file=test.html
         servletCtx.addServlet("FileServlet", new FileServlet()).
             addMapping("/files/*");
+
+        String legacyContextPath = servletCtx.getInitParameter("legacyContextPath");
+        if (legacyContextPath != null)
+        {
+            ServletRegistration.Dynamic redirectorDynamic = servletCtx.addServlet("RedirectorServlet", new RedirectorServlet(legacyContextPath));
+            redirectorDynamic.addMapping(legacyContextPath + "/*");
+            redirectorDynamic.setMultipartConfig(new MultipartConfigElement(SpringActionController.getTempUploadDir().getPath()));
+        }
     }
 
     @Override

api/src/org/labkey/api/view/RedirectorServlet.java

@@ -0,0 +1,45 @@
+package org.labkey.api.view;
+
+import java.io.IOException;
+
+import jakarta.servlet.ServletException;
+import jakarta.servlet.http.HttpServlet;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+
+/** Simple redirector to redirect and forward from legacy context paths to the root context */
+public class RedirectorServlet extends HttpServlet
+{
+    private final String _legacyContextPath;
+
+    public RedirectorServlet(String legacyContextPath)
+    {
+        if (!legacyContextPath.startsWith("/") || legacyContextPath.length() < 2)
+        {
+            throw new IllegalArgumentException("Legacy context path must start with / and cannot be the root context path. Invalid path: " + legacyContextPath + ", specified via context.legacyContextPath in application.properties");
+        }
+        _legacyContextPath = legacyContextPath;
+    }
+
+    @Override
+    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
+    {
+        if ("get".equalsIgnoreCase(request.getMethod()))
+        {
+            // Send a redirect to let the client know there's a new preferred URL
+            String originalUrl = request.getRequestURL().toString();
+            String redirectUrl = originalUrl.replaceFirst(_legacyContextPath, "");
+
+            response.setStatus(HttpServletResponse.SC_MOVED_PERMANENTLY);
+            response.setHeader("Location", redirectUrl);
+        }
+        else
+        {
+            // For non-GETs, use a forward so that we don't lose POST parameters, etc
+            String originalUri = request.getRequestURI();
+            String forwardUri = originalUri.replaceFirst(_legacyContextPath, "");
+
+            getServletContext().getRequestDispatcher(forwardUri).forward(request, response);
+        }
+    }
+}