/*
* This file is part of the Echo Web Application Framework (hereinafter "Echo").
* Copyright (C) 2002-2009 NextApp, Inc.
*
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*/
package nextapp.echo2.webrender;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import nextapp.echo2.webrender.service.CoreServices;
import nextapp.echo2.webrender.service.DebugPaneService;
/**
* Echo <code>HttpServlet</code> implementation.
*/
public abstract class WebRenderServlet extends HttpServlet {
/**
* A <code>ThreadLocal</code> reference to the
* <code>Connection</code> relevant to the current thread.
*/
private static final ThreadLocal activeConnection = new ThreadLocal();
/**
* A flag indicating whether caching should be disabled for all services.
* This flag is for testing purposes only, and should be disabled for
* production use.
*/
public static final boolean DISABLE_CACHING = false;
/**
* Request parameter identifying requested <code>Service</code>.
*/
public static final String SERVICE_ID_PARAMETER = "serviceId";
/**
* <code>Service</code> identifier of the 'default' service.
* The 'default' service is rendered when a client makes a request
* without a service identifier and a session DOES exist.
*/
public static final String SERVICE_ID_DEFAULT = "Echo.Default";
/**
* <code>Service</code> identifier of the 'new instance' service.
* The 'new instance' service is rendered when a client makes a request
* without a service identifier and a session DOES NOT exist..
*/
public static final String SERVICE_ID_NEW_INSTANCE = "Echo.NewInstance";
/**
* <code>Service</code> identifier of the 'session expired' service.
* The 'session expired' service is rendered when a client makes a
* request that has an identifier and is intended for an active session,
* but no session exists.
*/
public static final String SERVICE_ID_SESSION_EXPIRED = "Echo.Expired";
/**
* Global handler for multipart/form-data encoded HTTP requests.
*/
private static MultipartRequestWrapper multipartRequestWrapper;
private static final long startupTime = System.currentTimeMillis();
/**
* Global <code>ServiceRegistry</code>.
*/
private static final ServiceRegistry services = new ServiceRegistry();
static {
CoreServices.install(services);
services.add(DebugPaneService.INSTANCE);
}
/**
* An interface implemented by a supporting object that will handle
* multipart/form-data encoded HTTP requests. This type of request is
* required for file uploads. Echo does not provide internal support
* for file uploads, but instead provides hooks for file-upload handling
* components.
*/
public static interface MultipartRequestWrapper {
/**
* Returns a replacement <code>HttpServletRequest</code> object that
* may be used to handle a multipart/form-data encoded HTTP request.
*
* @param request The HTTP request provided from the servlet container
* that has multipart/form-data encoding.
* @return An HTTP request that is capable of handling
* multipart/form-data encoding.
*/
public HttpServletRequest getWrappedRequest(HttpServletRequest request)
throws IOException, ServletException;
}
/**
* Returns a reference to the <code>Connection</code> that is
* relevant to the current thread, or null if no connection is relevant.
*
* @return the relevant <code>Connection</code>
*/
public static final Connection getActiveConnection() {
return (Connection) activeConnection.get();
}
/**
* Returns the multipart/form-data encoded HTTP request handler.
*
* @return The multipart/form-data encoded HTTP request handler.
* @see #setMultipartRequestWrapper
*/
public static MultipartRequestWrapper getMultipartRequestWrapper() {
return multipartRequestWrapper;
}
/**
* Sets the multipart/form-data encoded HTTP request handler.
* The multipart request wrapper can only be set one time. It should be set
* in a static block of your Echo application. This method will disregard
* additional attempts to set the wrapper if the provided wrapper's class
* is identical to the existing one. If the wrapper is already set and the
* new wrapper object's class is different or the wrapper is null, an
* exception is thrown.
*
* @param multipartRequestWrapper The handler for multipart/form-data
* encoded HTTP requests.
* @throws IllegalStateException if the application attempts to change
* a previously set multipart request handler.
*/
public static final void setMultipartRequestWrapper(MultipartRequestWrapper multipartRequestWrapper) {
if (WebRenderServlet.multipartRequestWrapper == null) {
WebRenderServlet.multipartRequestWrapper = multipartRequestWrapper;
} else {
if (multipartRequestWrapper == null ||
!WebRenderServlet.multipartRequestWrapper.getClass().getName().equals(
multipartRequestWrapper.getClass().getName())) {
throw new IllegalStateException("MultipartRequestWrapper already set.");
}
}
}
/**
* Handles a GET request.
*
* @see #process(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
*/
public final void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
process(request, response);
}
/**
* Handles a POST request.
*
* @see #process(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
*/
public final void doPost(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
process(request, response);
}
/**
* Returns the service that corresponds to the specified Id.
*
* @param id The id of the service to return.
* @return The service corresponding to the specified Id.
*/
private static Service getService(UserInstance userInstance, String id) {
Service service;
service = services.get(id);
if (id == null) {
if (userInstance == null) {
id = SERVICE_ID_NEW_INSTANCE;
} else {
id = SERVICE_ID_DEFAULT;
}
} else {
if (userInstance == null) {
id = SERVICE_ID_SESSION_EXPIRED;
}
}
service = services.get(id);
if (service == null) {
if (SERVICE_ID_DEFAULT.equals(id)) {
throw new RuntimeException("Service not registered: SERVICE_ID_DEFAULT");
} else if (SERVICE_ID_NEW_INSTANCE.equals(id)) {
throw new RuntimeException("Service not registered: SERVICE_ID_NEW_INSTANCE");
} else if (SERVICE_ID_SESSION_EXPIRED.equals(id)) {
throw new RuntimeException("Service not registered: SERVICE_ID_SESSION_EXPIRED");
}
}
return service;
}
/**
* Retrieves the global <code>ServiceRegistry</code>.
*
* @return The global <code>ServiceRegistry</code>.
*/
public static ServiceRegistry getServiceRegistry() {
return services;
}
/**
* Processes a HTTP request and generates a response.
*
* @param request the incoming <code>HttpServletRequest</code>
* @param response the outgoing <code>HttpServletResponse</code>
*/
protected void process(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
Connection conn = null;
try {
conn = new Connection(this, request, response);
activeConnection.set(conn);
String serviceId = request.getParameter(SERVICE_ID_PARAMETER);
Service service = getService(conn.getUserInstance(), serviceId);
if (service == null) {
throw new ServletException("Service id \"" + serviceId + "\" not registered.");
}
int version = service.getVersion();
// Set caching directives.
if ((!DISABLE_CACHING) && version != Service.DO_NOT_CACHE) {
// Setting all of the following (possibly with the exception of "Expires")
// are *absolutely critical* in order to ensure proper caching of resources
// with Internet Explorer 6. Without "Last-Modified", IE6 appears to not
// cache images properly resulting in an substantially greater than expected
// performance impact.
response.setHeader("Cache-Control", "max-age=3600");
response.setDateHeader("Expires", System.currentTimeMillis() + (86400000));
response.setDateHeader("Last-Modified", startupTime);
} else {
response.setHeader("Pragma", "no-cache");
response.setHeader("Cache-Control", "no-store");
response.setHeader("Expires", "0");
}
// Put IE in compatibility mode
response.setHeader("X-UA-Compatible", "IE=8");
service.service(conn);
} catch (ServletException ex) {
if (conn != null) {
conn.disposeUserInstance();
}
throw(ex);
} catch (IOException ex) {
if (conn != null) {
conn.disposeUserInstance();
}
throw(ex);
} catch (RuntimeException ex) {
if (conn != null) {
conn.disposeUserInstance();
}
throw(ex);
} finally {
activeConnection.set(null);
}
}
}