| /** |
| * Copyright (C) 2008 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.Injector; |
| import com.google.inject.Key; |
| import com.google.inject.Scopes; |
| import com.google.inject.internal.util.Iterators; |
| import com.google.inject.spi.BindingTargetVisitor; |
| import com.google.inject.spi.ProviderInstanceBinding; |
| import com.google.inject.spi.ProviderWithExtensionVisitor; |
| |
| import java.io.IOException; |
| import java.util.Collections; |
| import java.util.Enumeration; |
| import java.util.HashMap; |
| import java.util.Map; |
| import java.util.Set; |
| import java.util.concurrent.atomic.AtomicReference; |
| import javax.servlet.ServletConfig; |
| import javax.servlet.ServletContext; |
| import javax.servlet.ServletException; |
| import javax.servlet.ServletRequest; |
| import javax.servlet.ServletResponse; |
| import javax.servlet.http.HttpServlet; |
| import javax.servlet.http.HttpServletRequest; |
| import javax.servlet.http.HttpServletRequestWrapper; |
| |
| import static com.google.inject.servlet.ManagedServletPipeline.REQUEST_DISPATCHER_REQUEST; |
| |
| /** |
| * An internal representation of a servlet definition mapped to a particular URI pattern. Also |
| * performs the request dispatch to that servlet. How nice and OO =) |
| * |
| * @author dhanji@gmail.com (Dhanji R. Prasanna) |
| */ |
| class ServletDefinition implements ProviderWithExtensionVisitor<ServletDefinition> { |
| private final String pattern; |
| private final Key<? extends HttpServlet> servletKey; |
| private final UriPatternMatcher patternMatcher; |
| private final Map<String, String> initParams; |
| // set only if this was bound using a servlet instance. |
| private final HttpServlet servletInstance; |
| |
| //always set in init, our servlet is always presumed to be a singleton |
| private final AtomicReference<HttpServlet> httpServlet = new AtomicReference<HttpServlet>(); |
| |
| public ServletDefinition(String pattern, Key<? extends HttpServlet> servletKey, |
| UriPatternMatcher patternMatcher, Map<String, String> initParams, HttpServlet servletInstance) { |
| this.pattern = pattern; |
| this.servletKey = servletKey; |
| this.patternMatcher = patternMatcher; |
| this.initParams = Collections.unmodifiableMap(new HashMap<String, String>(initParams)); |
| this.servletInstance = servletInstance; |
| } |
| |
| public ServletDefinition get() { |
| return this; |
| } |
| |
| public <B, V> V acceptExtensionVisitor(BindingTargetVisitor<B, V> visitor, |
| ProviderInstanceBinding<? extends B> binding) { |
| if(visitor instanceof ServletModuleTargetVisitor) { |
| if(servletInstance != null) { |
| return ((ServletModuleTargetVisitor<B, V>)visitor).visit( |
| new InstanceServletBindingImpl(initParams, |
| pattern, |
| servletInstance, |
| patternMatcher)); |
| } else { |
| return ((ServletModuleTargetVisitor<B, V>)visitor).visit( |
| new LinkedServletBindingImpl(initParams, |
| pattern, |
| servletKey, |
| patternMatcher)); |
| } |
| } else { |
| return visitor.visit(binding); |
| } |
| } |
| |
| boolean shouldServe(String uri) { |
| return patternMatcher.matches(uri); |
| } |
| |
| public void init(final ServletContext servletContext, Injector injector, |
| Set<HttpServlet> initializedSoFar) throws ServletException { |
| |
| // This absolutely must be a singleton, and so is only initialized once. |
| if (!Scopes.isSingleton(injector.getBinding(servletKey))) { |
| throw new ServletException("Servlets must be bound as singletons. " |
| + servletKey + " was not bound in singleton scope."); |
| } |
| |
| HttpServlet httpServlet = injector.getInstance(servletKey); |
| this.httpServlet.set(httpServlet); |
| |
| // Only fire init() if we have not appeared before in the filter chain. |
| if (initializedSoFar.contains(httpServlet)) { |
| return; |
| } |
| |
| //initialize our servlet with the configured context params and servlet context |
| httpServlet.init(new ServletConfig() { |
| public String getServletName() { |
| return servletKey.toString(); |
| } |
| |
| public ServletContext getServletContext() { |
| return servletContext; |
| } |
| |
| public String getInitParameter(String s) { |
| return initParams.get(s); |
| } |
| |
| public Enumeration getInitParameterNames() { |
| return Iterators.asEnumeration(initParams.keySet().iterator()); |
| } |
| }); |
| |
| // Mark as initialized. |
| initializedSoFar.add(httpServlet); |
| } |
| |
| public void destroy(Set<HttpServlet> destroyedSoFar) { |
| HttpServlet reference = httpServlet.get(); |
| |
| // Do nothing if this Servlet was invalid (usually due to not being scoped |
| // properly). According to Servlet Spec: it is "out of service", and does not |
| // need to be destroyed. |
| // Also prevent duplicate destroys to the same singleton that may appear |
| // more than once on the filter chain. |
| if (null == reference || destroyedSoFar.contains(reference)) { |
| return; |
| } |
| |
| try { |
| reference.destroy(); |
| } finally { |
| destroyedSoFar.add(reference); |
| } |
| } |
| |
| /** |
| * Wrapper around the service chain to ensure a servlet is servicing what it must and provides it |
| * with a wrapped request. |
| * |
| * @return Returns true if this servlet triggered for the given request. Or false if |
| * guice-servlet should continue dispatching down the servlet pipeline. |
| * |
| * @throws IOException If thrown by underlying servlet |
| * @throws ServletException If thrown by underlying servlet |
| */ |
| public boolean service(ServletRequest servletRequest, |
| ServletResponse servletResponse) throws IOException, ServletException { |
| |
| final HttpServletRequest request = (HttpServletRequest) servletRequest; |
| final String path = request.getRequestURI().substring(request.getContextPath().length()); |
| |
| final boolean serve = shouldServe(path); |
| |
| //invocations of the chain end at the first matched servlet |
| if (serve) { |
| doService(servletRequest, servletResponse); |
| } |
| |
| //return false if no servlet matched (so we can proceed down to the web.xml servlets) |
| return serve; |
| } |
| |
| /** |
| * Utility that delegates to the actual service method of the servlet wrapped with a contextual |
| * request (i.e. with correctly computed path info). |
| * |
| * We need to suppress deprecation coz we use HttpServletRequestWrapper, which implements |
| * deprecated API for backwards compatibility. |
| */ |
| void doService(final ServletRequest servletRequest, ServletResponse servletResponse) |
| throws ServletException, IOException { |
| |
| HttpServletRequest request = new HttpServletRequestWrapper( |
| (HttpServletRequest) servletRequest) { |
| private String path; |
| private boolean pathComputed = false; |
| //must use a boolean on the memo field, because null is a legal value (TODO no, it's not) |
| |
| private boolean pathInfoComputed = false; |
| private String pathInfo; |
| |
| @Override |
| public String getPathInfo() { |
| if (!isPathInfoComputed()) { |
| int servletPathLength = getServletPath().length(); |
| pathInfo = getRequestURI().substring(getContextPath().length()).replaceAll("[/]{2,}", "/"); |
| pathInfo = pathInfo.length() > servletPathLength ? pathInfo.substring(servletPathLength) : null; |
| |
| // Corner case: when servlet path and request path match exactly (without trailing '/'), |
| // then pathinfo is null |
| if ("".equals(pathInfo) && servletPathLength != 0) { |
| pathInfo = null; |
| } |
| |
| pathInfoComputed = true; |
| } |
| |
| return pathInfo; |
| } |
| |
| // NOTE(dhanji): These two are a bit of a hack to help ensure that request dipatcher-sent |
| // requests don't use the same path info that was memoized for the original request. |
| 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; |
| } |
| }; |
| |
| httpServlet.get().service(request, servletResponse); |
| } |
| |
| String getKey() { |
| return servletKey.toString(); |
| } |
| |
| String getPattern() { |
| return pattern; |
| } |
| } |