package org.mvnsearch.wx.servlet;
import org.apache.commons.codec.digest.DigestUtils;
import org.jetbrains.annotations.Nullable;
import org.mvnsearch.wx.WeixinMessage;
import org.mvnsearch.wx.WeixinUtils;
import org.mvnsearch.wx.rewrite.Conf;
import org.mvnsearch.wx.rewrite.RewrittenUrl;
import org.mvnsearch.wx.rewrite.UrlRewriter;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.*;
/**
* weixin robot servlet
*
* @author linux_china
*/
public class WexinRobotServlet extends HttpServlet {
/**
* token
*/
private String token;
/**
* pass code，用于调试，不执行签名检查
*/
private String passCode;
/**
* url rewriter
*/
private UrlRewriter urlRewriter;
/**
* init config
*
* @param config servlet config
* @throws ServletException servlet exception
*/
public void init(ServletConfig config) throws ServletException {
this.token = config.getInitParameter("token");
this.passCode = config.getInitParameter("passCode");
String confFile = config.getInitParameter("confFile");
try {
Conf conf = new Conf(config.getServletContext(), confFile);
this.urlRewriter = new UrlRewriter(conf);
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 微信公共平台认证接口
*
* @param request http servlet request
* @param response http servlet response
* @throws ServletException servlet exception
* @throws IOException io exception
*/
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String echostr = request.getParameter("echostr");
response.setContentType("text/plain; charset=UTF-8");
PrintWriter out = response.getWriter();
if (checkSignature(request.getQueryString(), getToken())) {
out.print(echostr);
} else {
out.print("false");
}
out.flush();
}
/**
* 微信消息接收接口
*
* @param request http servlet request
* @param response http servlet response
* @throws ServletException servlet exception
* @throws IOException io exception
*/
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//validate signature
boolean valid = checkSignature(request.getQueryString(), getToken());
if (valid) {
try {
WeixinMessage wxMsg = WeixinUtils.parseXML(request.getInputStream());
doMessage(wxMsg, request, response);
} catch (Exception e) {
response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
} finally {
WeixinMessageContext.clear();
}
} else {
send400(response);
}
}
/**
* 处理 weixin message
*
* @param wxMsg weixin message
* @param request http servlet request
* @param response http servlet response
* @throws Exception exception
*/
public void doMessage(WeixinMessage wxMsg, HttpServletRequest request, HttpServletResponse response) throws Exception {
WeixinMessageContext.setWeixinMessage(wxMsg);
WeixinMessageContext.setQueryString(request.getQueryString());
response.setContentType("text/xml; charset=UTF-8");
request.setAttribute("wxMsg", wxMsg);
RewrittenUrl rewrittenUrl = urlRewriter.processRequest(wxMsg, request, response);
if (rewrittenUrl != null) {
rewrittenUrl.doRewrite(request, response);
}
}
/**
* 验证签名
*
* @param queryString query string
* @return valid mark
*/
public boolean checkSignature(String queryString, @Nullable String token) {
if (token == null || token.isEmpty() || queryString == null) return false;
//pass code check
if (passCode != null && queryString.contains(passCode)) return true;
Map<String, String> params = new HashMap<String, String>();
for (String pair : queryString.split("&")) {
String[] temp = pair.split("=", 2);
params.put(temp[0], temp[1]);
}
List<String> elements = new ArrayList<String>();
elements.add(params.get("timestamp"));
elements.add(params.get("nonce"));
elements.add(token);
Collections.sort(elements);
StringBuilder seed = new StringBuilder();
for (String link : elements) {
seed.append(link);
}
return DigestUtils.sha1Hex(seed.toString()).equals(params.get("signature"));
}
/**
* get weixin call back token
*
* @return token
*/
@Nullable
protected String getToken() {
return this.token;
}
/**
* get query from query string
*
* @param request http servlet request
* @return query object
*/
protected Map<String, String> getQuery(HttpServletRequest request) {
String queryString = request.getQueryString();
if (queryString == null || !queryString.contains("=")) {
return Collections.emptyMap();
}
Map<String, String> query = new HashMap<String, String>();
for (String pair : queryString.split("&")) {
String[] parts = pair.split("=", 2);
if (parts.length == 2 && !parts[1].isEmpty()) {
query.put(parts[0], parts[1]);
}
}
return query;
}
/**
* send 400(bad request) response
*
* @param response response
*/
public void send400(HttpServletResponse response) {
try {
response.sendError(400);
} catch (Exception ignore) {
}
}
}