public void service(ServletRequest request, ServletResponse response)
throws ServletException, IOException {
// Get print writer.
PrintWriter pw = response.getWriter();
// Get enumeration of parameter names.
Enumeration e = request.getParameterNames();
// Display parameter names and values.
while (e.hasMoreElements()) {
String pname = (String) e.nextElement();
pw.print(pname + " = ");
String pvalue = request.getParameter(pname);
pw.println(pvalue);
}
pw.close();
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
String longAddr = null, shortAddr, s, transactionKey = null;
int count;
boolean ignorable = false;
synchronized (simultaneousRequestsByShortIPAddr) {
if (totalSimultaneousRequests >= maxTotalSimultaneousRequests) {
log.error(
"This system has exceeded the maxTotalSimultaneousRequests limit of "
+ maxTotalSimultaneousRequests);
log.error(simultaneousRequestsByShortIPAddr);
for (String str : simultaneousRequests) log.error(str);
((HttpServletResponse) response).setStatus(HttpURLConnection.HTTP_UNAVAILABLE);
response.setContentType("text/html");
PrintWriter writer = response.getWriter();
writer.println("<html><body><h1>Service Temporarily Unavailable</h1>");
writer.println(
"The system is experiencing a severe load and is temporarily unable to accept new requests");
if (contactInfo != null)
writer.println("<p>Contact " + contactInfo + " for more information</p>");
writer.println("</body></html>");
writer.close();
return;
}
if (addressInHeader != null) {
@SuppressWarnings("unchecked")
Enumeration<String> addrs = ((HttpServletRequest) request).getHeaders(addressInHeader);
while (addrs.hasMoreElements()) {
longAddr = addrs.nextElement();
if (longAddr == null) {
if (++addressInHeaderErrorCount < 10)
log.error("Expected a " + addressInHeader + " header but got null");
continue;
}
if (longAddr.lastIndexOf('.') >= 0) break;
}
}
if (longAddr == null) longAddr = request.getRemoteAddr();
int i = longAddr.lastIndexOf('.');
if (i < 0) {
log.error("bogus IP address: '" + longAddr + "'");
longAddr = "0.0.0.0";
}
shortAddr = longAddr.substring(0, i); // trim off 4th number group
// that lets us spot requests from clusters
s = equivalentAddresses.get(shortAddr); // map one short addr to another?
if (s != null) shortAddr = s;
if (ignorableAddresses.contains(shortAddr)) {
ignorable = true;
} else {
Integer icount = simultaneousRequestsByShortIPAddr.get(shortAddr);
if (icount != null) count = icount;
else count = 0;
int maxSimultaneousRequests =
(maxTotalSimultaneousRequests - totalSimultaneousRequests) / 4;
if (maxSimultaneousRequests == 0) maxSimultaneousRequests = 1;
if (count >= maxSimultaneousRequests) {
log.error(
"IP addr "
+ shortAddr
+ ".* has exceeded "
+ maxSimultaneousRequests
+ " simultaneous requests!");
log.error("maxTotalSimultaneousRequests=" + maxTotalSimultaneousRequests);
log.error("totalSimultaneousRequests=" + totalSimultaneousRequests);
for (String str : simultaneousRequests) log.error(str);
//
// ((HttpServletResponse)response).setStatus(HttpURLConnection.HTTP_TOO_MANY_REQUESTS); //
// someday
((HttpServletResponse) response).setStatus(429); // too many requests
response.setContentType("text/html");
PrintWriter writer = response.getWriter();
writer.println(
"<html><head><title>Too Many Requests</title></head><body><h1>Too Many Requests</h1>");
writer.println(
"You have exceeded the maximum simultaneous request value of "
+ maxSimultaneousRequests);
writer.println("<p>This message and your IP address have been logged and reported</p>");
if (contactInfo != null)
writer.println("<p>Contact " + contactInfo + " for more information</p>");
writer.println("</body></html>");
writer.close();
return;
}
simultaneousRequestsByShortIPAddr.put(shortAddr, count + 1);
icount = totalRequests.get(shortAddr);
if (icount != null) count = icount;
else count = 0;
totalRequests.put(shortAddr, count + 1);
totalSimultaneousRequests++;
transactionKey =
new StringBuilder((new Date(System.currentTimeMillis())).toString())
.append('|')
.append(shortAddr)
.append('|')
.append(((HttpServletRequest) request).getQueryString())
.toString();
simultaneousRequests.add(transactionKey);
}
}
try {
HttpServletResponseWrapper wrapper =
new HttpServletResponseWrapper((HttpServletResponse) response);
chain.doFilter(request, wrapper);
} finally {
if (!ignorable)
synchronized (simultaneousRequestsByShortIPAddr) {
totalSimultaneousRequests--;
simultaneousRequests.remove(transactionKey);
count = simultaneousRequestsByShortIPAddr.get(shortAddr);
if (count == 1) // prune them from the table
simultaneousRequestsByShortIPAddr.remove(shortAddr);
else simultaneousRequestsByShortIPAddr.put(shortAddr, count - 1);
}
}
Calendar c = new GregorianCalendar();
int hour = c.get(Calendar.HOUR_OF_DAY);
if (hour == 0 && nextReportingHour == 24) { // new day!
// you could reset your daily limits table here
nextReportingHour = 0;
}
if (hour >= nextReportingHour) { // generate the hourly report
// you could reset your hourly limits table here
nextReportingHour = hour + 1;
if (log.isInfoEnabled()) {
HashMap<String, Integer> map = new LinkedHashMap<String, Integer>();
List<String> yourMapKeys = new ArrayList<String>(totalRequests.keySet());
List<Integer> yourMapValues = new ArrayList<Integer>(totalRequests.values());
TreeSet<Integer> sortedSet = new TreeSet<Integer>(yourMapValues);
Integer[] sortedArray = sortedSet.descendingSet().toArray(new Integer[0]);
int size = sortedArray.length;
for (int i = 0; i < size; i++)
map.put(yourMapKeys.get(yourMapValues.indexOf(sortedArray[i])), sortedArray[i]);
Iterator<String> it = map.keySet().iterator();
String key;
StringBuilder sb = new StringBuilder("Top 10 users in the last hour");
for (int i = 0; i < 10 && it.hasNext(); i++) {
key = it.next();
sb.append("\n ").append(key).append(" : ").append(map.get(key));
}
log.info(sb);
}
totalRequests.clear();
}
}