| /** |
| * Copyright (C) 2006 Google Inc. |
| * |
| * Licensed 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 com.google.inject.servlet; |
| |
| import com.google.inject.Inject; |
| import com.google.inject.OutOfScopeException; |
| import java.io.IOException; |
| import java.lang.ref.WeakReference; |
| import java.util.logging.Logger; |
| import javax.servlet.Filter; |
| import javax.servlet.FilterChain; |
| import javax.servlet.FilterConfig; |
| import javax.servlet.ServletContext; |
| import javax.servlet.ServletException; |
| import javax.servlet.ServletRequest; |
| import javax.servlet.ServletResponse; |
| import javax.servlet.http.HttpServletRequest; |
| import javax.servlet.http.HttpServletResponse; |
| |
| /** |
| * <p> |
| * Apply this filter in web.xml above all other filters (typically), to all requests where you plan |
| * to use servlet scopes. This is also needed in order to dispatch requests to injectable filters |
| * and servlets: |
| * <pre> |
| * <filter> |
| * <filter-name>guiceFilter</filter-name> |
| * <filter-class><b>com.google.inject.servlet.GuiceFilter</b></filter-class> |
| * </filter> |
| * |
| * <filter-mapping> |
| * <filter-name>guiceFilter</filter-name> |
| * <url-pattern>/*</url-pattern> |
| * </filter-mapping> |
| * </pre> |
| * |
| * This filter must appear before every filter that makes use of Guice injection or servlet |
| * scopes functionality. Typically, you will only register this filter in web.xml and register |
| * any other filters (and servlets) using a {@link ServletModule}. |
| * |
| * @author crazybob@google.com (Bob Lee) |
| * @author dhanji@gmail.com (Dhanji R. Prasanna) |
| */ |
| public class GuiceFilter implements Filter { |
| static final ThreadLocal<Context> localContext = new ThreadLocal<Context>(); |
| static volatile FilterPipeline pipeline = new DefaultFilterPipeline(); |
| |
| /** |
| * We allow both the static and dynamic versions of the pipeline to exist. |
| */ |
| @Inject |
| private final FilterPipeline injectedPipeline = null; |
| |
| /** Used to inject the servlets configured via {@link ServletModule} */ |
| static volatile WeakReference<ServletContext> servletContext = |
| new WeakReference<ServletContext>(null); |
| |
| private static final String MULTIPLE_INJECTORS_WARNING = |
| "Multiple Servlet injectors detected. This is a warning " |
| + "indicating that you have more than one " |
| + GuiceFilter.class.getSimpleName() + " running " |
| + "in your web application. If this is deliberate, you may safely " |
| + "ignore this message. If this is NOT deliberate however, " |
| + "your application may not work as expected."; |
| |
| //VisibleForTesting |
| @Inject |
| static void setPipeline(FilterPipeline pipeline) { |
| |
| // This can happen if you create many injectors and they all have their own |
| // servlet module. This is legal, caveat a small warning. |
| if (GuiceFilter.pipeline instanceof ManagedFilterPipeline) { |
| Logger.getLogger(GuiceFilter.class.getName()).warning(MULTIPLE_INJECTORS_WARNING); |
| } |
| |
| // We overwrite the default pipeline |
| GuiceFilter.pipeline = pipeline; |
| } |
| |
| //VisibleForTesting |
| static void reset() { |
| pipeline = new DefaultFilterPipeline(); |
| } |
| |
| public void doFilter(ServletRequest servletRequest, |
| ServletResponse servletResponse, FilterChain filterChain) |
| throws IOException, ServletException { |
| |
| Context previous = localContext.get(); |
| |
| // Prefer the injected pipeline, but fall back on the static one for web.xml users. |
| FilterPipeline filterPipeline = null != injectedPipeline ? injectedPipeline : pipeline; |
| |
| try { |
| localContext.set(new Context((HttpServletRequest) servletRequest, |
| (HttpServletResponse) servletResponse)); |
| |
| //dispatch across the servlet pipeline, ensuring web.xml's filterchain is honored |
| filterPipeline.dispatch(servletRequest, servletResponse, filterChain); |
| |
| } finally { |
| localContext.set(previous); |
| } |
| } |
| |
| static HttpServletRequest getRequest() { |
| return getContext().getRequest(); |
| } |
| |
| static HttpServletResponse getResponse() { |
| return getContext().getResponse(); |
| } |
| |
| static ServletContext getServletContext() { |
| return servletContext.get(); |
| } |
| |
| static Context getContext() { |
| Context context = localContext.get(); |
| if (context == null) { |
| throw new OutOfScopeException("Cannot access scoped object. Either we" |
| + " are not currently inside an HTTP Servlet request, or you may" |
| + " have forgotten to apply " + GuiceFilter.class.getName() |
| + " as a servlet filter for this request."); |
| } |
| return context; |
| } |
| |
| static class Context { |
| |
| final HttpServletRequest request; |
| final HttpServletResponse response; |
| |
| Context(HttpServletRequest request, HttpServletResponse response) { |
| this.request = request; |
| this.response = response; |
| } |
| |
| HttpServletRequest getRequest() { |
| return request; |
| } |
| |
| HttpServletResponse getResponse() { |
| return response; |
| } |
| } |
| |
| public void init(FilterConfig filterConfig) throws ServletException { |
| final ServletContext servletContext = filterConfig.getServletContext(); |
| |
| // Store servlet context in a weakreference, for injection |
| GuiceFilter.servletContext = new WeakReference<ServletContext>(servletContext); |
| |
| // In the default pipeline, this is a noop. However, if replaced |
| // by a managed pipeline, a lazy init will be triggered the first time |
| // dispatch occurs. |
| FilterPipeline filterPipeline = null != injectedPipeline ? injectedPipeline : pipeline; |
| filterPipeline.initPipeline(servletContext); |
| } |
| |
| public void destroy() { |
| |
| try { |
| // Destroy all registered filters & servlets in that order |
| FilterPipeline filterPipeline = null != injectedPipeline ? injectedPipeline : pipeline; |
| filterPipeline.destroyPipeline(); |
| |
| } finally { |
| reset(); |
| servletContext.clear(); |
| } |
| } |
| } |