/*
* Copyright 2007-2008 the original author or authors.
*
* 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 org.impalaframework.web.integration;
import java.io.IOException;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.impalaframework.web.WebConstants;
import org.impalaframework.web.helper.WebServletUtils;
import org.impalaframework.web.integration.ModuleProxyUtils;
import org.impalaframework.web.integration.RequestModuleMapper;
import org.impalaframework.web.spring.servlet.InternalModuleServlet;
/**
* <p>
* Servlet who's job it is to figure out the mapping to a particular request and
* redirect this to the correct module servlet instance. Works by picking out the first portion of the
* servlet path. For example, if the application is called webapp. A URL pointing to this application
* might be <i>http://localhost:8080/webapp/mymodule/test.htm</i>. Then <code>ModuleProxyServlet</code> will
* attempt to identify the module using the first part of the URL after the context path: that is 'mymodule'.
* It then looks for a servlet published to the servlet context using an attribute name which
* includes 'mymodule'. If this servlet is found, the request is passed directly to the servlet.
* </p>
* <p>
* Note that the servlet needs to "published" loaded, probably using <code>ServletFactoryBean</code> or a subclass,
* and needs to be published to the <code>ServletContext</code>. This will be the case for <code>InternalFrameworkIntegrationServlet</code>
* and <code>InternalModuleServlet</code>.
* </p>
*
* @see InternalFrameworkIntegrationServlet
* @see InternalModuleServlet
* @author Phil Zoio
*/
public class ModuleProxyServlet extends HttpServlet {
private static final Log logger = LogFactory.getLog(ModuleProxyServlet.class);
private static final long serialVersionUID = 1L;
private RequestModuleMapper requestModuleMapper;
public ModuleProxyServlet() {
super();
}
@Override
public void init(ServletConfig config) throws ServletException {
super.init(config);
this.requestModuleMapper = newRequestModuleMapper(config);
this.requestModuleMapper.init(config);
}
protected RequestModuleMapper newRequestModuleMapper(ServletConfig config) {
final String requestModuleMapperClass = config.getInitParameter(WebConstants.REQUEST_MODULE_MAPPER_CLASS_NAME);
return ModuleProxyUtils.newRequestModuleMapper(requestModuleMapperClass);
}
@Override
public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
ModuleProxyUtils.maybeLogRequest(request, logger);
ServletContext context = getServletContext();
doService(request, response, context);
}
void doService(HttpServletRequest request, HttpServletResponse response,
ServletContext context)
throws ServletException, IOException {
String moduleName = getModuleName(request);
HttpServlet moduleServlet = null;
if (moduleName != null) {
moduleServlet = WebServletUtils.getModuleServlet(context, moduleName);
if (moduleServlet != null) {
//explicitly go through service method
HttpServletRequest wrappedRequest = wrappedRequest(request, context, moduleName);
moduleServlet.service(wrappedRequest, response);
} else {
logger.warn("No redirection possible for servlet path " + request.getServletPath() + ", module name " + moduleName);
}
} else {
logger.warn("Not possible to figure out module name from servlet path " + request.getServletPath());
}
}
String getModuleName(HttpServletRequest request) {
return requestModuleMapper.getModuleForRequest(request);
}
protected HttpServletRequest wrappedRequest(HttpServletRequest request, ServletContext servletContext, String moduleName) {
return ModuleIntegrationUtils.getWrappedRequest(request, servletContext, moduleName);
}
}