/* ------------------------------------------------------------ */
@Override
public void resume() {
AsyncContext context = _context;
if (context == null) throw new IllegalStateException();
_resumed = true;
_context.dispatch();
}
@Override
public void onEvent(byte[] data, long seq, boolean endOfBatch) throws Exception {
crc32.update(data);
long crc = crc32.getValue();
byte[] md5 = md5Digest.digest(data);
byte[] sha1 = sha1Digest.digest(data);
Data d = new Data(String.valueOf(crc), toHex(md5), toHex(sha1));
int size = contexts.size();
for (int i = 0; i < size; i++) {
AsyncContext context = contexts.poll();
if (null != context) {
context.getRequest().setAttribute("data", d);
try {
context.dispatch();
} catch (Exception e) {
}
} else {
break;
}
}
crc32.reset();
md5Digest.reset();
sha1Digest.reset();
}
@Override
public void onTimeout(AsyncEvent event) throws IOException {
// Remove before it's redispatched, so it won't be
// redispatched again at the end of the filtering.
AsyncContext asyncContext = event.getAsyncContext();
_queues[priority].remove(asyncContext);
asyncContext.dispatch();
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// Only set the status on the first call (the dispatch will trigger
// another call to this Servlet)
if (resp.getStatus() != HttpServletResponse.SC_BAD_REQUEST) {
resp.setStatus(HttpServletResponse.SC_BAD_REQUEST);
AsyncContext ac = req.startAsync();
ac.dispatch();
}
}
/*
* (non-Javadoc)
*
* @see java.lang.Runnable#run()
*/
@Override
public void run() {
try {
if (timerValue > 0) {
// Simulate long running operation
Timer.startNew(timerValue);
}
} catch (InterruptedException e) {
throw new IllegalStateException("Interrupted");
}
// Dispatch or complete
if (useDispatch) {
if (dispatchPath != null) {
actx.dispatch(dispatchPath);
} else {
actx.dispatch();
}
} else {
actx.complete();
}
logger.log("Async processing finished");
}
private synchronized void chat(
HttpServletRequest request, HttpServletResponse response, String username, String message)
throws IOException {
Map<String, Member> room = _rooms.get(request.getPathInfo());
if (room != null) {
// Post chat to all members
for (Member m : room.values()) {
synchronized (m) {
m._queue.add(username); // from
m._queue.add(message); // chat
// wakeup member if polling
AsyncContext async = m._async.get();
if (async != null & m._async.compareAndSet(async, null)) async.dispatch();
}
}
}
response.setContentType("text/json;charset=utf-8");
PrintWriter out = response.getWriter();
out.print("{action:\"chat\"}");
}
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
boolean accepted = false;
try {
Boolean suspended = (Boolean) request.getAttribute(_suspended);
if (suspended == null) {
accepted = _passes.tryAcquire(getWaitMs(), TimeUnit.MILLISECONDS);
if (accepted) {
request.setAttribute(_suspended, Boolean.FALSE);
if (LOG.isDebugEnabled()) LOG.debug("Accepted {}", request);
} else {
request.setAttribute(_suspended, Boolean.TRUE);
int priority = getPriority(request);
AsyncContext asyncContext = request.startAsync();
long suspendMs = getSuspendMs();
if (suspendMs > 0) asyncContext.setTimeout(suspendMs);
asyncContext.addListener(_listeners[priority]);
_queues[priority].add(asyncContext);
if (LOG.isDebugEnabled()) LOG.debug("Suspended {}", request);
return;
}
} else {
if (suspended) {
request.setAttribute(_suspended, Boolean.FALSE);
Boolean resumed = (Boolean) request.getAttribute(_resumed);
if (resumed == Boolean.TRUE) {
_passes.acquire();
accepted = true;
if (LOG.isDebugEnabled()) LOG.debug("Resumed {}", request);
} else {
// Timeout! try 1 more time.
accepted = _passes.tryAcquire(getWaitMs(), TimeUnit.MILLISECONDS);
if (LOG.isDebugEnabled()) LOG.debug("Timeout {}", request);
}
} else {
// Pass through resume of previously accepted request.
_passes.acquire();
accepted = true;
if (LOG.isDebugEnabled()) LOG.debug("Passthrough {}", request);
}
}
if (accepted) {
chain.doFilter(request, response);
} else {
if (LOG.isDebugEnabled()) LOG.debug("Rejected {}", request);
((HttpServletResponse) response).sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE);
}
} catch (InterruptedException e) {
((HttpServletResponse) response).sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE);
} finally {
if (accepted) {
for (int p = _queues.length - 1; p >= 0; --p) {
AsyncContext asyncContext = _queues[p].poll();
if (asyncContext != null) {
ServletRequest candidate = asyncContext.getRequest();
Boolean suspended = (Boolean) candidate.getAttribute(_suspended);
if (suspended == Boolean.TRUE) {
candidate.setAttribute(_resumed, Boolean.TRUE);
asyncContext.dispatch();
break;
}
}
}
_passes.release();
}
}
}
protected void doFilter(
HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
throws IOException, ServletException {
if (!isEnabled()) {
filterChain.doFilter(request, response);
return;
}
// Look for the rate tracker for this request.
RateTracker tracker = (RateTracker) request.getAttribute(__TRACKER);
if (tracker == null) {
// This is the first time we have seen this request.
if (LOG.isDebugEnabled()) LOG.debug("Filtering {}", request);
// Get a rate tracker associated with this request, and record one hit.
tracker = getRateTracker(request);
// Calculate the rate and check it is over the allowed limit
final boolean overRateLimit = tracker.isRateExceeded(System.currentTimeMillis());
// Pass it through if we are not currently over the rate limit.
if (!overRateLimit) {
if (LOG.isDebugEnabled()) LOG.debug("Allowing {}", request);
doFilterChain(filterChain, request, response);
return;
}
// We are over the limit.
// So either reject it, delay it or throttle it.
long delayMs = getDelayMs();
boolean insertHeaders = isInsertHeaders();
switch ((int) delayMs) {
case -1:
{
// Reject this request.
LOG.warn(
"DOS ALERT: Request rejected ip={}, session={}, user={}",
request.getRemoteAddr(),
request.getRequestedSessionId(),
request.getUserPrincipal());
if (insertHeaders) response.addHeader("DoSFilter", "unavailable");
response.sendError(getTooManyCode());
return;
}
case 0:
{
// Fall through to throttle the request.
LOG.warn(
"DOS ALERT: Request throttled ip={}, session={}, user={}",
request.getRemoteAddr(),
request.getRequestedSessionId(),
request.getUserPrincipal());
request.setAttribute(__TRACKER, tracker);
break;
}
default:
{
// Insert a delay before throttling the request,
// using the suspend+timeout mechanism of AsyncContext.
LOG.warn(
"DOS ALERT: Request delayed={}ms, ip={}, session={}, user={}",
delayMs,
request.getRemoteAddr(),
request.getRequestedSessionId(),
request.getUserPrincipal());
if (insertHeaders) response.addHeader("DoSFilter", "delayed");
request.setAttribute(__TRACKER, tracker);
AsyncContext asyncContext = request.startAsync();
if (delayMs > 0) asyncContext.setTimeout(delayMs);
asyncContext.addListener(new DoSTimeoutAsyncListener());
return;
}
}
}
if (LOG.isDebugEnabled()) LOG.debug("Throttling {}", request);
// Throttle the request.
boolean accepted = false;
try {
// Check if we can afford to accept another request at this time.
accepted = _passes.tryAcquire(getMaxWaitMs(), TimeUnit.MILLISECONDS);
if (!accepted) {
// We were not accepted, so either we suspend to wait,
// or if we were woken up we insist or we fail.
Boolean throttled = (Boolean) request.getAttribute(__THROTTLED);
long throttleMs = getThrottleMs();
if (throttled != Boolean.TRUE && throttleMs > 0) {
int priority = getPriority(request, tracker);
request.setAttribute(__THROTTLED, Boolean.TRUE);
if (isInsertHeaders()) response.addHeader("DoSFilter", "throttled");
AsyncContext asyncContext = request.startAsync();
request.setAttribute(_suspended, Boolean.TRUE);
if (throttleMs > 0) asyncContext.setTimeout(throttleMs);
asyncContext.addListener(_listeners[priority]);
_queues[priority].add(asyncContext);
if (LOG.isDebugEnabled()) LOG.debug("Throttled {}, {}ms", request, throttleMs);
return;
}
Boolean resumed = (Boolean) request.getAttribute(_resumed);
if (resumed == Boolean.TRUE) {
// We were resumed, we wait for the next pass.
_passes.acquire();
accepted = true;
}
}
// If we were accepted (either immediately or after throttle)...
if (accepted) {
// ...call the chain.
if (LOG.isDebugEnabled()) LOG.debug("Allowing {}", request);
doFilterChain(filterChain, request, response);
} else {
// ...otherwise fail the request.
if (LOG.isDebugEnabled()) LOG.debug("Rejecting {}", request);
if (isInsertHeaders()) response.addHeader("DoSFilter", "unavailable");
response.sendError(getTooManyCode());
}
} catch (InterruptedException e) {
LOG.ignore(e);
response.sendError(getTooManyCode());
} finally {
if (accepted) {
try {
// Wake up the next highest priority request.
for (int p = _queues.length - 1; p >= 0; --p) {
AsyncContext asyncContext = _queues[p].poll();
if (asyncContext != null) {
ServletRequest candidate = asyncContext.getRequest();
Boolean suspended = (Boolean) candidate.getAttribute(_suspended);
if (suspended == Boolean.TRUE) {
if (LOG.isDebugEnabled()) LOG.debug("Resuming {}", request);
candidate.setAttribute(_resumed, Boolean.TRUE);
asyncContext.dispatch();
break;
}
}
}
} finally {
_passes.release();
}
}
}
}
