/*
* Copyright (c) 2009, 2010, 2011, 2012, B3log Team
*
* 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.b3log.latke.servlet;
import org.b3log.latke.servlet.renderer.AbstractHTTPResponseRenderer;
import org.b3log.latke.Keys;
import org.b3log.latke.cache.PageCaches;
import org.b3log.latke.util.Strings;
import java.util.logging.Level;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.logging.Logger;
import javax.servlet.RequestDispatcher;
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.b3log.latke.Latkes;
import org.json.JSONException;
import org.json.JSONObject;
import org.b3log.latke.servlet.renderer.HTTP404Renderer;
import org.b3log.latke.util.StaticResources;
import org.b3log.latke.util.Stopwatchs;
/**
* Front controller for HTTP request dispatching.
*
* @author <a href="mailto:DL88250@gmail.com">Liang Ding</a>
* @version 1.0.1.9, May 11, 2012
*/
public final class HTTPRequestDispatcher extends HttpServlet {
/**
* Default serial version uid.
*/
private static final long serialVersionUID = 1L;
/**
* Logger.
*/
private static final Logger LOGGER = Logger.getLogger(HTTPRequestDispatcher.class.getName());
/**
* Default Servlet name used by Tomcat, Jetty, JBoss, and GlassFish.
*/
private static final String COMMON_DEFAULT_SERVLET_NAME = "default";
/**
* Default Servlet name used by Google App Engine.
*/
private static final String GAE_DEFAULT_SERVLET_NAME = "_ah_default";
/**
* Default Servlet name used by Resin.
*/
private static final String RESIN_DEFAULT_SERVLET_NAME = "resin-file";
/**
* Default Servlet name used by WebLogic.
*/
private static final String WEBLOGIC_DEFAULT_SERVLET_NAME = "FileServlet";
/**
* Default Servlet name used by WebSphere.
*/
private static final String WEBSPHERE_DEFAULT_SERVLET_NAME = "SimpleFileServlet";
/**
* Current default servlet name.
*/
private String defaultServletName;
/**
* Initializes this servlet.
*
* <p>
* Scans classpath for discovering request processors, configured the 'default' servlet for static resource processing.
* </p>
*
* @throws ServletException servlet exception
* @see RequestProcessors#discover()
*/
@Override
public void init() throws ServletException {
Stopwatchs.start("Discovering Request Processors");
try {
LOGGER.info("Discovering request processors....");
RequestProcessors.discover();
LOGGER.info("Discovered request processors");
} catch (final Exception e) {
LOGGER.log(Level.SEVERE, "Initializes request processors failed", e);
} finally {
Stopwatchs.end();
}
final ServletContext servletContext = getServletContext();
if (servletContext.getNamedDispatcher(COMMON_DEFAULT_SERVLET_NAME) != null) {
defaultServletName = COMMON_DEFAULT_SERVLET_NAME;
} else if (servletContext.getNamedDispatcher(GAE_DEFAULT_SERVLET_NAME) != null) {
defaultServletName = GAE_DEFAULT_SERVLET_NAME;
} else if (servletContext.getNamedDispatcher(RESIN_DEFAULT_SERVLET_NAME) != null) {
defaultServletName = RESIN_DEFAULT_SERVLET_NAME;
} else if (servletContext.getNamedDispatcher(WEBLOGIC_DEFAULT_SERVLET_NAME) != null) {
defaultServletName = WEBLOGIC_DEFAULT_SERVLET_NAME;
} else if (servletContext.getNamedDispatcher(WEBSPHERE_DEFAULT_SERVLET_NAME) != null) {
defaultServletName = WEBSPHERE_DEFAULT_SERVLET_NAME;
} else {
throw new IllegalStateException("Unable to locate the default servlet for serving static content. "
+ "Please set the 'defaultServletName' property explicitly.");
// TODO: Loads from local.properties
}
LOGGER.log(Level.CONFIG, "The default servlet for serving static resource is [{0}]", defaultServletName);
}
/**
* Serves.
*
* @param request the specified HTTP servlet request
* @param response the specified HTTP servlet response
* @throws ServletException servlet exception
* @throws IOException io exception
*/
@Override
protected void service(final HttpServletRequest request, final HttpServletResponse response) throws ServletException, IOException {
final String resourcePath = request.getPathTranslated();
final String requestURI = request.getRequestURI();
LOGGER.log(Level.FINEST, "Request[contextPath={0}, pathTranslated={1}, requestURI={2}]",
new Object[]{request.getContextPath(), resourcePath, requestURI});
if (StaticResources.isStatic(request)) {
final RequestDispatcher requestDispatcher = getServletContext().getNamedDispatcher(defaultServletName);
if (null == requestDispatcher) {
throw new IllegalStateException("A RequestDispatcher could not be located for the default servlet ["
+ this.defaultServletName + "]");
}
requestDispatcher.forward(request, response);
return;
}
final long startTimeMillis = System.currentTimeMillis();
request.setAttribute(Keys.HttpRequest.START_TIME_MILLIS, startTimeMillis);
if (Latkes.isPageCacheEnabled()) {
final String queryString = request.getQueryString();
String pageCacheKey = (String) request.getAttribute(Keys.PAGE_CACHE_KEY);
if (Strings.isEmptyOrNull(pageCacheKey)) {
pageCacheKey = PageCaches.getPageCacheKey(requestURI, queryString);
request.setAttribute(Keys.PAGE_CACHE_KEY, pageCacheKey);
}
}
request.setCharacterEncoding("UTF-8");
response.setCharacterEncoding("UTF-8");
final HTTPRequestContext context = new HTTPRequestContext();
context.setRequest(request);
context.setResponse(response);
dispatch(context);
}
/**
* Dispatches with the specified context.
*
* @param context the specified specified context
* @throws ServletException servlet exception
* @throws IOException io exception
*/
public static void dispatch(final HTTPRequestContext context) throws ServletException, IOException {
final HttpServletRequest request = context.getRequest();
String requestURI = (String) request.getAttribute(Keys.HttpRequest.REQUEST_URI);
if (Strings.isEmptyOrNull(requestURI)) {
requestURI = request.getRequestURI();
}
String method = (String) request.getAttribute(Keys.HttpRequest.REQUEST_METHOD);
if (Strings.isEmptyOrNull(method)) {
method = request.getMethod();
}
LOGGER.log(Level.FINER, "Request[requestURI={0}, method={1}]", new Object[]{requestURI, method});
try {
final Object processorMethodRet = RequestProcessors.invoke(requestURI, Latkes.getContextPath(), method, context);
} catch (final Exception e) {
final String exceptionTypeName = e.getClass().getName();
LOGGER.log(Level.FINER,
"Occured error while processing request[requestURI={0}, method={1}, exceptionTypeName={2}, errorMsg={3}]",
new Object[]{requestURI, method, exceptionTypeName, e.getMessage()});
if ("com.google.apphosting.api.ApiProxy$OverQuotaException".equals(exceptionTypeName)) {
PageCaches.removeAll();
context.getResponse().sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE);
return;
}
throw new ServletException(e);
} catch (final Error e) {
final Runtime runtime = Runtime.getRuntime();
LOGGER.log(Level.FINER, "Memory status[total={0}, max={1}, free={2}]",
new Object[]{runtime.totalMemory(), runtime.maxMemory(), runtime.freeMemory()});
LOGGER.log(Level.SEVERE, e.getMessage(), e);
throw e;
}
// XXX: processor method ret?
final HttpServletResponse response = context.getResponse();
if (response.isCommitted()) { // Sends rdirect or send error
final PrintWriter writer = response.getWriter();
writer.flush();
writer.close();
return;
}
AbstractHTTPResponseRenderer renderer = context.getRenderer();
if (null == renderer) {
renderer = new HTTP404Renderer();
}
renderer.render(context);
}
/**
* Gets the query string(key1=value2&key2=value2&....) for the
* specified HTTP servlet request.
*
* @param request the specified HTTP servlet request
* @return a json object converts from query string, if can't convert the
* query string, returns an empty json object;
* @throws JSONException json exception
*/
private JSONObject getQueryStringJSONObject(final HttpServletRequest request) throws JSONException {
JSONObject ret = null;
final String tmp = request.getQueryString();
if (null == tmp) {
return new JSONObject();
}
LOGGER.log(Level.FINEST, "Client is using QueryString[{0}]", tmp);
final StringBuilder sb = new StringBuilder();
sb.append("{");
final String[] split = tmp.split("&");
for (int i = 0; i < split.length; i++) {
final String query = split[i];
final String[] kv = query.split("=");
if (kv.length != 2) {
return new JSONObject();
}
final String key = kv[0];
final String value = kv[1];
sb.append("\"");
sb.append(key);
sb.append("\":");
sb.append("\"");
sb.append(value);
sb.append("\"");
if (i < split.length - 1) {
sb.append(",");
}
}
sb.append("}");
ret = new JSONObject(sb.toString());
return ret;
}
}