/*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you 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 javax.faces.webapp;

 import java.io.IOException;

 import java.lang.reflect.Method;

 import java.lang.reflect.InvocationTargetException;

 import java.util.List;

 import javax.faces.FactoryFinder;

 import javax.faces.FacesException;

 import javax.faces.context.FacesContext;

 import javax.faces.context.FacesContextFactory;

 import javax.faces.lifecycle.Lifecycle;

 import javax.faces.lifecycle.LifecycleFactory;

 import javax.servlet.Servlet;

 import javax.servlet.ServletConfig;

 import javax.servlet.ServletException;

 import javax.servlet.ServletRequest;

 import javax.servlet.ServletResponse;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFWebConfigParam;

 /**

  * see Javadoc of <a href="http://java.sun.com/javaee/javaserverfaces/1.2/docs/api/index.html">JSF Specification</a>

  *

  * @author Manfred Geiler (latest modification by $Author: lu4242 $)

  * @version $Revision: 888211 $ $Date: 2009-12-07 20:07:19 -0500 (Mon, 07 Dec 2009) $

  */

 public final class FacesServlet

         implements Servlet

 {

     private static final Log log = LogFactory.getLog(FacesServlet.class);

     /**

      * Comma separated list of URIs of (additional) faces config files.

      * (e.g. /WEB-INF/my-config.xml)See JSF 1.0 PRD2, 10.3.2

      * Attention: You do not need to put /WEB-INF/faces-config.xml in here.

      */

     @JSFWebConfigParam(since="1.1")

     public static final String CONFIG_FILES_ATTR = "javax.faces.CONFIG_FILES";

     /**

      * Identify the Lifecycle instance to be used.

      */

     @JSFWebConfigParam(since="1.1")

     public static final String LIFECYCLE_ID_ATTR = "javax.faces.LIFECYCLE_ID";

     private static final String SERVLET_INFO = "FacesServlet of the MyFaces API implementation";

     /**

      * Indicate if myfaces is responsible to handle errors. 

      * See http://wiki.apache.org/myfaces/Handling_Server_Errors for details. 

      */

     @JSFWebConfigParam(defaultValue="true",expectedValues="true,false", since="1.2.4")

     private static final String ERROR_HANDLING_PARAMETER = "org.apache.myfaces.ERROR_HANDLING";

     /**

      * If you want to choose a different class for handling the exception.

      * <p> 

      * The error-handler needs to include the following methods:

      * </p>

      * <ul>

      * <li>handleException(FacesContext fc, Exception ex)</li>

      * <li>handleExceptionList(FacesContext facesContext, List exceptionList)</li>

      * <li>handleThrowable(FacesContext facesContext, Throwable ex)</li>

      * </ul>

      */

     @JSFWebConfigParam(since="1.2.4")

     private static final String ERROR_HANDLER_PARAMETER = "org.apache.myfaces.ERROR_HANDLER";

     private static final String ERROR_HANDLING_EXCEPTION_LIST = "org.apache.myfaces.errorHandling.exceptionList";

     private ServletConfig _servletConfig;

     private FacesContextFactory _facesContextFactory;

     private Lifecycle _lifecycle;

     public FacesServlet()

     {

         super();

     }

     public void destroy()

     {

         _servletConfig = null;

         _facesContextFactory = null;

         _lifecycle = null;

         if(log.isTraceEnabled()) log.trace("destroy");

     }

     public ServletConfig getServletConfig()

     {

         return _servletConfig;

     }

     public String getServletInfo()

     {

         return SERVLET_INFO;

     }

     private String getLifecycleId()

     {

         //1. check for Servlet's init-param

         //2. check for global context parameter

         //3. use default Lifecycle Id, if none of them was provided

         String serLifecycleId = _servletConfig.getInitParameter(LIFECYCLE_ID_ATTR);

         String appLifecycleId = _servletConfig.getServletContext().getInitParameter(LIFECYCLE_ID_ATTR);

         appLifecycleId = serLifecycleId == null ? appLifecycleId : serLifecycleId;

         return appLifecycleId != null ? appLifecycleId : LifecycleFactory.DEFAULT_LIFECYCLE;

     }

     public void init(ServletConfig servletConfig)

             throws ServletException

     {

         if(log.isTraceEnabled()) log.trace("init begin");

         _servletConfig = servletConfig;

         _facesContextFactory = (FacesContextFactory)FactoryFinder.getFactory(FactoryFinder.FACES_CONTEXT_FACTORY);

         //TODO: null-check for Weblogic, that tries to initialize Servlet before ContextListener

         //Javadoc says: Lifecycle instance is shared across multiple simultaneous requests, it must be implemented in a thread-safe manner.

         //So we can acquire it here once:

         LifecycleFactory lifecycleFactory = (LifecycleFactory)FactoryFinder.getFactory(FactoryFinder.LIFECYCLE_FACTORY);

         _lifecycle = lifecycleFactory.getLifecycle(getLifecycleId());

         if(log.isTraceEnabled()) log.trace("init end");

     }

     public void service(ServletRequest request,

                         ServletResponse response)

             throws IOException,

                    ServletException

     {

         HttpServletRequest httpRequest = ((HttpServletRequest) request);

         String pathInfo = httpRequest.getPathInfo();

         // if it is a prefix mapping ...

         if (pathInfo != null

                 && (pathInfo.startsWith("/WEB-INF") || pathInfo

                         .startsWith("/META-INF")))

         {

             StringBuffer buffer = new StringBuffer();

             buffer.append(" Someone is trying to access a secure resource : ").append(pathInfo);

             buffer.append("\n remote address is ").append(httpRequest.getRemoteAddr());

             buffer.append("\n remote host is ").append(httpRequest.getRemoteHost());

             buffer.append("\n remote user is ").append(httpRequest.getRemoteUser());

             buffer.append("\n request URI is ").append(httpRequest.getRequestURI());

             log.warn(buffer.toString());

             // Why does RI return a 404 and not a 403, SC_FORBIDDEN ?

             ((HttpServletResponse) response)

                     .sendError(HttpServletResponse.SC_NOT_FOUND);

             return;

         }

         if(log.isTraceEnabled()) log.trace("service begin");

         FacesContext facesContext = prepareFacesContext(request, response);

         try {

             _lifecycle.execute(facesContext);

             if (!handleQueuedExceptions(facesContext))

             {

                 _lifecycle.render(facesContext);

             }

         }

         catch (Exception e)

         {

             handleLifecycleException(facesContext, e);

         }

         catch (Throwable e)

         {

             handleLifecycleThrowable(facesContext, e);

         }

         finally

         {

             facesContext.release();

         }

         if(log.isTraceEnabled()) log.trace("service end");

     }

     /**This method makes sure we see an exception page also

      * if an exception has been thrown in UIInput.updateModel();

      * In this method, according to the spec, we may not rethrow the

      * exception, so we add it to a list and process it here.

      *

      * Attention: if you use redirects, the exceptions will get lost - exactly

      * like in the case of FacesMessages. If you want them to be taken over to the

      * next request, you should try the redirect-tracker of MyFaces.

      *

      * @param facesContext

      * @throws FacesException

      */

     private boolean handleQueuedExceptions(FacesContext facesContext) throws IOException, ServletException {

         List li = (List)

                 facesContext.getExternalContext().getRequestMap().get(ERROR_HANDLING_EXCEPTION_LIST);

         if(li != null && li.size()>=1)  {

             //todo: for now, we only handle the first exception out of the list - we just rethrow this

             //first exception.

             //in the end, we should enable the error handler to show all the exceptions at once

             boolean errorHandling = getBooleanValue(facesContext.getExternalContext().getInitParameter(ERROR_HANDLING_PARAMETER), true);

             if(errorHandling) {

                 String errorHandlerClass = facesContext.getExternalContext().getInitParameter(ERROR_HANDLER_PARAMETER);            

                 if(errorHandlerClass != null) {

                     try {

                         Class clazz = Class.forName(errorHandlerClass);

                         Object errorHandler = clazz.newInstance();

                         Method m = clazz.getMethod("handleExceptionList", new Class[]{FacesContext.class,List.class});

                         m.invoke(errorHandler, new Object[]{facesContext, li});

                     }

                     catch(ClassNotFoundException ex) {

                         throw new ServletException("Error-Handler : " +errorHandlerClass+ " was not found. Fix your web.xml-parameter : "+ERROR_HANDLER_PARAMETER,ex);

                     } catch (IllegalAccessException ex) {

                         throw new ServletException("Constructor of error-Handler : " +errorHandlerClass+ " is not accessible. Error-Handler is specified in web.xml-parameter : "+ERROR_HANDLER_PARAMETER,ex);

                     } catch (InstantiationException ex) {

                         throw new ServletException("Error-Handler : " +errorHandlerClass+ " could not be instantiated. Error-Handler is specified in web.xml-parameter : "+ERROR_HANDLER_PARAMETER,ex);

                     } catch (NoSuchMethodException ex) {

                         //Handle in the old way, since no custom method handleExceptionList found,

                         //throwing the first FacesException on the list.

                         throw (FacesException) li.get(0);

                     } catch (InvocationTargetException ex) {

                         throw new ServletException("Excecution of method handleException in Error-Handler : " +errorHandlerClass+ " threw an exception. Error-Handler is specified in web.xml-parameter : "+ERROR_HANDLER_PARAMETER,ex);

                     }

                 }

                 else {

                     _ErrorPageWriter.handleExceptionList(facesContext, li);

                 }

             }

             else {

                 _ErrorPageWriter.throwException((Exception) li.get(0));

             }

             return true;

         }

         return false;

     }

     private void handleLifecycleException(FacesContext facesContext, Exception e) throws IOException, ServletException {

         boolean errorHandling = getBooleanValue(facesContext.getExternalContext().getInitParameter(ERROR_HANDLING_PARAMETER), true);

         if(errorHandling) {

             String errorHandlerClass = facesContext.getExternalContext().getInitParameter(ERROR_HANDLER_PARAMETER);

             if(errorHandlerClass != null) {

                 try {

                     Class clazz = Class.forName(errorHandlerClass);

                     Object errorHandler = clazz.newInstance();

                     Method m = clazz.getMethod("handleException", new Class[]{FacesContext.class,Exception.class});

                     m.invoke(errorHandler, new Object[]{facesContext, e});

                 }

                 catch(ClassNotFoundException ex) {

                     throw new ServletException("Error-Handler : " +errorHandlerClass+ " was not found. Fix your web.xml-parameter : "+ERROR_HANDLER_PARAMETER,ex);

                 } catch (IllegalAccessException ex) {

                     throw new ServletException("Constructor of error-Handler : " +errorHandlerClass+ " is not accessible. Error-Handler is specified in web.xml-parameter : "+ERROR_HANDLER_PARAMETER,ex);

                 } catch (InstantiationException ex) {

                     throw new ServletException("Error-Handler : " +errorHandlerClass+ " could not be instantiated. Error-Handler is specified in web.xml-parameter : "+ERROR_HANDLER_PARAMETER,ex);

                 } catch (NoSuchMethodException ex) {

                     log.error("Error-Handler : " +errorHandlerClass+ " did not have a method with name : handleException and parameters : javax.faces.context.FacesContext, java.lang.Exception. Error-Handler is specified in web.xml-parameter : "+ERROR_HANDLER_PARAMETER,ex);

                     //Try to look if it is implemented more general method handleThrowable

                     handleLifecycleThrowable(facesContext, e);

                 } catch (InvocationTargetException ex) {

                     throw new ServletException("Excecution of method handleException in Error-Handler : " +errorHandlerClass+ " caused an exception. Error-Handler is specified in web.xml-parameter : "+ERROR_HANDLER_PARAMETER,ex);

                 }

             }

             else {

                 _ErrorPageWriter.handleException(facesContext, e);

             }

         }

         else {

             _ErrorPageWriter.throwException(e);

         }

     }

     private void handleLifecycleThrowable(FacesContext facesContext, Throwable e) throws IOException, ServletException {

         boolean errorHandling = getBooleanValue(facesContext.getExternalContext().getInitParameter(ERROR_HANDLING_PARAMETER), true);

         if(errorHandling) {

             String errorHandlerClass = facesContext.getExternalContext().getInitParameter(ERROR_HANDLER_PARAMETER);            

             if(errorHandlerClass != null) {

                 try {

                     Class clazz = Class.forName(errorHandlerClass);

                     Object errorHandler = clazz.newInstance();

                     Method m = clazz.getMethod("handleThrowable", new Class[]{FacesContext.class,Throwable.class});

                     m.invoke(errorHandler, new Object[]{facesContext, e});

                 }

                 catch(ClassNotFoundException ex) {

                     throw new ServletException("Error-Handler : " +errorHandlerClass+ " was not found. Fix your web.xml-parameter : "+ERROR_HANDLER_PARAMETER,ex);

                 } catch (IllegalAccessException ex) {

                     throw new ServletException("Constructor of error-Handler : " +errorHandlerClass+ " is not accessible. Error-Handler is specified in web.xml-parameter : "+ERROR_HANDLER_PARAMETER,ex);

                 } catch (InstantiationException ex) {

                     throw new ServletException("Error-Handler : " +errorHandlerClass+ " could not be instantiated. Error-Handler is specified in web.xml-parameter : "+ERROR_HANDLER_PARAMETER,ex);

                 } catch (NoSuchMethodException ex) {

                     throw new ServletException("Error-Handler : " +errorHandlerClass+ " did not have a method with name : handleException and parameters : javax.faces.context.FacesContext, java.lang.Exception. Error-Handler is specified in web.xml-parameter : "+ERROR_HANDLER_PARAMETER,ex);

                 } catch (InvocationTargetException ex) {

                     throw new ServletException("Excecution of method handleException in Error-Handler : " +errorHandlerClass+ " threw an exception. Error-Handler is specified in web.xml-parameter : "+ERROR_HANDLER_PARAMETER,ex);

                 }

             }

             else {

                 _ErrorPageWriter.handleThrowable(facesContext, e);

             }

         }

         else {

             _ErrorPageWriter.throwException(e);

         }

     }

     private static boolean getBooleanValue(String initParameter, boolean defaultVal) {

         if(initParameter == null || initParameter.trim().length()==0)

             return defaultVal;

         return (initParameter.equalsIgnoreCase("on") || initParameter.equals("1") || initParameter.equalsIgnoreCase("true"));

     }

     private FacesContext prepareFacesContext(ServletRequest request, ServletResponse response) {

         FacesContext facesContext

                 = _facesContextFactory.getFacesContext(_servletConfig.getServletContext(),

                                                        request,

                                                        response,

                                                        _lifecycle);

         return facesContext;

     }

 }