Migrated attachment for Guice issue 807, comment 5

fix_issue_807.patch

From 6b7a884bb097aa3d70e71fbc5e5c6143d8d5be43 Mon Sep 17 00:00:00 2001
From: James Moger <james.moger@gitblit.com>
Date: Thu, 12 Jun 2014 11:26:46 -0400
Subject: [PATCH] Properly construct a wrapped servlet request before calling
 Filter.doFilter()

---
 .../inject/servlet/FilterChainInvocation.java      |  8 ++-
 .../google/inject/servlet/FilterDefinition.java    | 79 ++++++++++++++++++++++
 .../com/google/inject/servlet/ServletTest.java     |  3 +-
 3 files changed, 88 insertions(+), 2 deletions(-)

diff --git a/extensions/servlet/src/com/google/inject/servlet/FilterChainInvocation.java b/extensions/servlet/src/com/google/inject/servlet/FilterChainInvocation.java
index b4112cf..278815f 100644
--- a/extensions/servlet/src/com/google/inject/servlet/FilterChainInvocation.java
+++ b/extensions/servlet/src/com/google/inject/servlet/FilterChainInvocation.java
@@ -76,10 +76,16 @@ class FilterChainInvocation implements FilterChain {
     try {
       Filter filter = findNextFilter(request);
       if (filter != null) {
+        // wrap the servlet request with filter-specific request info
+        FilterDefinition filterDefinition = filterDefinitions[index];
+        HttpServletRequest filterRequest = filterDefinition.wrapRequest(request);
+        // replace the filter context
+        GuiceFilter.localContext.set(new GuiceFilter.Context(originalRequest, filterRequest, response));
+
         // call to the filter, which can either consume the request or
         // recurse back into this method. (in which case we will go to find the next filter,
         // or dispatch to the servlet if no more filters are left)
-        filter.doFilter(servletRequest, servletResponse, this);
+        filter.doFilter(filterRequest, servletResponse, this);
       } else {
         //we've reached the end of the filterchain, let's try to dispatch to a servlet
         final boolean serviced = servletPipeline.service(servletRequest, servletResponse);
diff --git a/extensions/servlet/src/com/google/inject/servlet/FilterDefinition.java b/extensions/servlet/src/com/google/inject/servlet/FilterDefinition.java
index ff1e5b6..f900937 100644
--- a/extensions/servlet/src/com/google/inject/servlet/FilterDefinition.java
+++ b/extensions/servlet/src/com/google/inject/servlet/FilterDefinition.java
@@ -15,6 +15,8 @@
  */
 package com.google.inject.servlet;
 
+import static com.google.inject.servlet.ManagedServletPipeline.REQUEST_DISPATCHER_REQUEST;
+
 import com.google.common.collect.Iterators;
 import com.google.inject.Injector;
 import com.google.inject.Key;
@@ -35,6 +37,7 @@ import javax.servlet.FilterConfig;
 import javax.servlet.ServletContext;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletRequestWrapper;
 
 /**
  * An internal representation of a filter definition against a particular URI pattern.
@@ -160,6 +163,82 @@ class FilterDefinition implements ProviderWithExtensionVisitor<FilterDefinition>
     }
   }
 
+  HttpServletRequest wrapRequest(final HttpServletRequest servletRequest) {
+    HttpServletRequest request = new HttpServletRequestWrapper(servletRequest) {
+      private boolean pathComputed;
+      private String path;
+
+      private boolean pathInfoComputed;
+      private String pathInfo;
+
+      @Override
+      public String getPathInfo() {
+        if (!isPathInfoComputed()) {
+          String servletPath = getServletPath();
+          int servletPathLength = servletPath.length();
+          String requestUri = getRequestURI();
+          pathInfo = requestUri.substring(getContextPath().length()).replaceAll("[/]{2,}", "/");
+          // See: http://code.google.com/p/google-guice/issues/detail?id=372
+          if (pathInfo.startsWith(servletPath)) {
+            pathInfo = pathInfo.substring(servletPathLength);
+            // Corner case: when servlet path & request path match exactly (without trailing '/'),
+            // then pathinfo is null.
+            if (pathInfo.isEmpty() && servletPathLength > 0) {
+              pathInfo = null;
+            }
+          } else {
+            pathInfo = null; // we know nothing additional about the URI.
+          }
+          pathInfoComputed = true;
+        }
+
+        return pathInfo;
+      }
+
+      // NOTE(dhanji): These two are a bit of a hack to help ensure that request dispatcher-sent
+      // requests don't use the same path info that was memoized for the original request.
+      // NOTE(iqshum): I don't think this is possible, since the dispatcher-sent request would
+      // perform its own wrapping.
+      private boolean isPathInfoComputed() {
+        return pathInfoComputed
+          && !(null != servletRequest.getAttribute(REQUEST_DISPATCHER_REQUEST));
+      }
+
+      private boolean isPathComputed() {
+        return pathComputed
+          && !(null != servletRequest.getAttribute(REQUEST_DISPATCHER_REQUEST));
+      }
+
+      @Override
+      public String getServletPath() {
+        return computePath();
+      }
+
+      @Override
+      public String getPathTranslated() {
+        final String info = getPathInfo();
+
+        return (null == info) ? null : getRealPath(info);
+      }
+
+      // Memoizer pattern.
+      private String computePath() {
+        if (!isPathComputed()) {
+          String servletPath = super.getServletPath();
+          path = patternMatcher.extractPath(servletPath);
+          pathComputed = true;
+
+          if (null == path) {
+            path = servletPath;
+          }
+        }
+
+        return path;
+      }
+    };
+    return request;
+  }
+
   //VisibleForTesting
   Filter getFilter() {
     return filter.get();
diff --git a/extensions/servlet/test/com/google/inject/servlet/ServletTest.java b/extensions/servlet/test/com/google/inject/servlet/ServletTest.java
index beb0873..2645857 100644
--- a/extensions/servlet/test/com/google/inject/servlet/ServletTest.java
+++ b/extensions/servlet/test/com/google/inject/servlet/ServletTest.java
@@ -240,7 +240,8 @@ public class ServletTest extends TestCase {
             assertSame(req, servletReqProvider.get());
             assertSame(req, reqProvider.get());
             if (previousReq[0] != null) {
-              assertEquals(req, previousReq[0]);
+              ServletRequest wrappedReq = ((HttpServletRequestWrapper) req).getRequest();
+              assertEquals(wrappedReq, previousReq[0]);
             }
 
             assertSame(resp, servletRespProvider.get());
-- 
1.9.1