package org.jrest4guice.rest;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.jrest4guice.rest.commons.sna.SNAIdRequestServlet;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
/**
*
* @author <a href="mailto:zhangyouqun@gmail.com">cnoss (QQ:86895156)</a>
*
*/
public abstract class AbstractJRest4GuiceFilter implements Filter {
/**
*
*/
private static final long serialVersionUID = -4393521946859930914L;
/**
* rest服务资源的url前缀
*/
protected String urlPrefix;
/**
* 忽略处理的资源扩展名
*/
protected static final Set<String> extNameExcludes = new HashSet<String>();
static {
extNameExcludes.add("js");
extNameExcludes.add("jsp");
extNameExcludes.add("jspa");
extNameExcludes.add("do");
extNameExcludes.add("action");
extNameExcludes.add("html");
extNameExcludes.add("htm");
extNameExcludes.add("jpg");
extNameExcludes.add("gif");
extNameExcludes.add("png");
extNameExcludes.add("bmp");
extNameExcludes.add("swf");
extNameExcludes.add("css");
extNameExcludes.add("htc");
}
/**
* 会话服务器的url
*/
private String sessionServerUrl;
protected long sessionTimeOut = 15;
/*
* (non-Javadoc)
*
* @see javax.servlet.Filter#init(javax.servlet.FilterConfig)
*/
public void init(FilterConfig config) throws ServletException {
// 初始化需要被过滤器忽略的资源扩展名
String _extNameExcludes = config.getInitParameter("extNameExcludes");
if (_extNameExcludes != null && !_extNameExcludes.trim().equals("")) {
String[] exts = _extNameExcludes.split(",");
for (String ext : exts)
extNameExcludes.add(ext);
}
this.sessionServerUrl = config.getInitParameter("sessionServerUrl");
// 初始化rest服务的url前缀
this.initUrlPrefix(config);
this.executeInit(config);
}
/**
* 过滤器的主入口
*/
public void doFilter(ServletRequest servletReqest,
ServletResponse servletResponse, FilterChain filterChain)
throws IOException, ServletException {
HttpServletRequest hRequest = (HttpServletRequest) servletReqest;
HttpServletResponse hResponse = (HttpServletResponse) servletResponse;
if (this.sessionServerUrl != null) {
// 检测当前应用是否充当了会话服务器的职能，如果是，则直接进入下一个过滤器
boolean isSessionServerUrl = this.sessionServerUrl.replace(
hRequest.getRequestURL().toString(), "").trim().equals("");
if (isSessionServerUrl) {
filterChain.doFilter(hRequest, hResponse);
return;
}
HttpSession session = hRequest.getSession();
// 从当前会话中获取snaId
String snaId = (String) session
.getAttribute(SNAIdRequestServlet.SNA_ID);
if (snaId == null) {// 如果没有标识，则尝试从参数中获取
snaId = hRequest.getParameter(SNAIdRequestServlet.SNA_ID);
}
String queryString = hRequest.getQueryString();
// 如果snaId为null，则重定向到sna会话服务器，获取新的snaId
if (snaId == null || snaId.trim().equals("")) {
if (queryString != null && !queryString.equals(""))
queryString = "&" + queryString;
else
queryString = "";
// 从SNA会话服务器上获取snaId
String redirectUrl = this.sessionServerUrl + "?sourceUrl="
+ hRequest.getRequestURL() + ";jsessionid="
+ session.getId() + queryString;
hResponse.sendRedirect(redirectUrl);
return;
}
// 保存snaId到当前会话
if (session.getAttribute(SNAIdRequestServlet.SNA_ID) == null) {
session.setAttribute(SNAIdRequestServlet.SNA_ID, snaId);
// 构造查询参数
queryString = queryString.replaceAll(SNAIdRequestServlet.SNA_ID
+ "=" + snaId, "");
if (queryString.startsWith("&"))
queryString = queryString.replaceFirst("&", "?");
// 重定向回原始页面
hResponse.sendRedirect(hRequest.getRequestURL() + queryString);
return;
}
}
String uri = hRequest.getRequestURI();
uri = uri.replace(hRequest.getContextPath(), "");
// 忽略以下的文件不处理
String _uri = uri.trim().toLowerCase();
int index = _uri.lastIndexOf(".");
if (index != -1) {
String ext_name = _uri.substring(index + 1);
if (extNameExcludes.contains(ext_name)) {
filterChain.doFilter(hRequest, hResponse);
return;
}
}
if (uri == null || "".equals(uri) || "/".equals(uri)) {
filterChain.doFilter(hRequest, hResponse);
return;
}
this.executeFilter(hRequest, hResponse, filterChain, uri);
}
protected abstract void executeInit(FilterConfig config)
throws ServletException;
protected abstract void executeFilter(HttpServletRequest servletReqest,
HttpServletResponse servletResponse, FilterChain filterChain,
String uri) throws IOException, ServletException;
/**
* 实始化rest服务的url前缀
*
* @param config
*/
private void initUrlPrefix(FilterConfig config) {
try {
FilterInfoParser servletInfoParser = new FilterInfoParser();
servletInfoParser.parse(config.getServletContext());
Map<String, String> filterInfos = servletInfoParser.getFilterInfos();
this.sessionTimeOut = Integer.parseInt(servletInfoParser.getSessionTimeout());
String urlPattern = filterInfos.get(config.getFilterName());
this.urlPrefix = urlPattern;
if (urlPattern.endsWith("*"))
this.urlPrefix = urlPattern.substring(0,
urlPattern.length() - 1);
if (this.urlPrefix.equals("/"))
this.urlPrefix = null;
} catch (Exception e) {
e.printStackTrace();
}
}
/*
* (non-Javadoc)
*
* @see javax.servlet.Filter#destroy()
*/
public void destroy() {
}
class FilterInfoParser extends DefaultHandler {
private boolean startParse;
private String name;
private String urlPattern;
private StringBuffer content;
private String sessionTimeout = "15";
private Map<String, String> filterInfos;
private Map<String, String> servletInfos;
public FilterInfoParser() {
this.content = new StringBuffer();
this.filterInfos = new HashMap<String, String>(0);
this.servletInfos = new HashMap<String, String>(0);
}
public void startElement(String uri, String localName, String qName,
Attributes attributes) throws SAXException {
this.clearContent();
if (qName.equalsIgnoreCase("filter-mapping")
|| qName.equalsIgnoreCase("servlet-mapping")) {
startParse = true;
}
if (startParse
&& (qName.equalsIgnoreCase("filter-name") || qName
.equalsIgnoreCase("servlet-name"))) {
name = null;
}
if (startParse && qName.equalsIgnoreCase("url-pattern")) {
urlPattern = null;
}
if (qName.equalsIgnoreCase("session-timeout")) {
this.clearContent();
}
}
private void clearContent() {
content.delete(0, content.length());
}
public void characters(char ch[], int start, int length)
throws SAXException {
content.append(ch, start, length);
}
public void endElement(String uri, String localName, String qName)
throws SAXException {
if (qName.equalsIgnoreCase("filter-mapping")) {
startParse = false;
this.filterInfos.put(this.name, this.urlPattern);
}
if (qName.equalsIgnoreCase("servlet-mapping")) {
startParse = false;
this.servletInfos.put(this.name, this.urlPattern);
}
if (startParse
&& (qName.equalsIgnoreCase("filter-name") || qName
.equalsIgnoreCase("servlet-name"))) {
name = content.toString();
this.clearContent();
}
if (startParse && qName.equalsIgnoreCase("url-pattern")) {
urlPattern = content.toString();
this.clearContent();
}
if (qName.equalsIgnoreCase("session-timeout")) {
this.sessionTimeout = content.toString();
this.clearContent();
}
}
public final Map<String, String> getFilterInfos() {
return filterInfos;
}
public final Map<String, String> getServletInfos() {
return servletInfos;
}
public String getSessionTimeout() {
return sessionTimeout;
}
public void parse(ServletContext servletContext)
throws Exception {
SAXParserFactory factory = SAXParserFactory.newInstance();
factory.setNamespaceAware(false);
factory.setValidating(false);
SAXParser parser = factory.newSAXParser();
servletContext.getContextPath();
InputStream resourceAsStream = null;
try {
resourceAsStream = new FileInputStream(servletContext
.getRealPath("WEB-INF/web.xml"));
parser.parse(resourceAsStream, this);
}finally{
if(resourceAsStream != null)
resourceAsStream.close();
}
}
}
}