/*
* Copyright 2012 JBoss, by Red Hat, Inc
*
* 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.jboss.errai.bus.client.framework.transports;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.jboss.errai.bus.client.api.RetryInfo;
import org.jboss.errai.bus.client.api.base.DefaultErrorCallback;
import org.jboss.errai.bus.client.api.base.TransportIOException;
import org.jboss.errai.bus.client.api.messaging.Message;
import org.jboss.errai.bus.client.api.messaging.MessageCallback;
import org.jboss.errai.bus.client.framework.BusState;
import org.jboss.errai.bus.client.framework.ClientMessageBusImpl;
import org.jboss.errai.bus.client.util.BusToolsCli;
import org.jboss.errai.common.client.api.Assert;
import org.jboss.errai.common.client.protocols.MessageParts;
import org.jboss.errai.common.client.util.LogUtil;
import com.google.gwt.http.client.Request;
import com.google.gwt.http.client.RequestBuilder;
import com.google.gwt.http.client.RequestCallback;
import com.google.gwt.http.client.RequestException;
import com.google.gwt.http.client.RequestTimeoutException;
import com.google.gwt.http.client.Response;
import com.google.gwt.http.client.URL;
import com.google.gwt.user.client.Timer;
/**
* @author Mike Brock
*/
public class HttpPollingHandler implements TransportHandler, TransportStatistics {
public static int THROTTLE_TIME_MS = 175;
public static int POLL_FREQUENCY_MS = 500;
private boolean configured;
private final MessageCallback messageCallback;
private final ClientMessageBusImpl messageBus;
private final List<Message> heldMessages = new ArrayList<Message>();
private final List<Message> undeliveredMessages = new ArrayList<Message>();
private int txNumber = 0;
private int rxNumber = 0;
private long connectedTime = -1;
private long lastTx = System.currentTimeMillis();
private int measuredLatency = -1;
private final Timer throttleTimer = new Timer() {
@Override
public void run() {
transmit(getDeferredToSend());
}
};
/**
* Set to true when an outbound transmission is in progress. This flag is designed to guard against more than
* one transmission from happening at once.
*/
boolean txActive = false;
/**
* Set to true when an inbound transmission (ie. a long poll) is in progress. This flag is designed to guard
* against more than one transmission from happening at once.
*/
boolean rxActive = false;
int rxRetries = 0;
int txRetries = 0;
/**
* Keeps track of all pending requests, both incoming (receive builders) and
* outgoing (send builders). Entries in this set are normally responsible for
* removing themselves when they get the success or error callback. However,
* when we stop the bus on purpose, the stop() method explicitly cancels
* everything in this set. In that case, the RequestCallbacks are never
* invoked.
*/
private final Set<RxInfo> pendingRequests = new LinkedHashSet<RxInfo>();
/**
* Note that this could be any subtype of LongPollRequestCallback, including
* ShortPollRequestCallback or NoPollRequestCallback.
* <p/>
* Instance invariant: this field is never set to null.
*/
private LongPollRequestCallback receiveCommCallback = new NoPollRequestCallback();
private HttpPollingHandler(final MessageCallback messageCallback, final ClientMessageBusImpl messageBus) {
this.messageCallback = Assert.notNull(messageCallback);
this.messageBus = messageBus;
}
public static HttpPollingHandler newLongPollingInstance(final MessageCallback messageCallback,
final ClientMessageBusImpl messageBus) {
final HttpPollingHandler handler = new HttpPollingHandler(messageCallback, messageBus);
handler.receiveCommCallback = handler.new LongPollRequestCallback();
return handler;
}
public static HttpPollingHandler newShortPollingInstance(final MessageCallback messageCallback,
final ClientMessageBusImpl messageBus) {
final HttpPollingHandler handler = new HttpPollingHandler(messageCallback, messageBus);
handler.receiveCommCallback = handler.new ShortPollRequestCallback();
return handler;
}
public static HttpPollingHandler newNoPollingInstance(final MessageCallback messageCallback,
final ClientMessageBusImpl messageBus) {
final HttpPollingHandler handler = new HttpPollingHandler(messageCallback, messageBus);
handler.receiveCommCallback = handler.new NoPollRequestCallback();
return handler;
}
@Override
public void configure(final Message capabilitiesMessage) {
configured = true;
}
@Override
public boolean isUsable() {
return configured;
}
@Override
public void start() {
receiveCommCallback.schedule();
}
private boolean throttleMessages(final List<Message> txMessages) {
final int window = throttleOutgoing();
if (window <= 0) {
heldMessages.addAll(txMessages);
throttleTimer.schedule(-window);
return true;
}
else {
return false;
}
}
private List<Message> getDeferredToSend() {
throttleTimer.cancel();
try {
return new ArrayList<Message>(heldMessages);
}
finally {
heldMessages.clear();
}
}
//TODO: reimplement throttling
@Override
public void transmit(final List<Message> txMessages) {
if (txMessages.isEmpty()) {
return;
}
//LogUtil.log("[bus] HttpPollingHandler.transmit(" + txMessages + ")");
final List<Message> toSend = new ArrayList<Message>();
boolean canDefer = true;
final Map<String, String> specialParms;
if (txMessages.size() == 1 && txMessages.get(0).hasResource(EXTRA_URI_PARMS_RESOURCE)) {
toSend.add(txMessages.get(0));
specialParms = txMessages.get(0).getResource(Map.class, EXTRA_URI_PARMS_RESOURCE);
}
else {
for (final Message message : txMessages) {
if (message.hasPart(MessageParts.PriorityProcessing)) {
canDefer = false;
break;
}
else if (message.hasResource(EXTRA_URI_PARMS_RESOURCE)) {
throw new IllegalStateException("cannot send payload. messages with special URI parms must be sent one at a time.");
}
}
if (canDefer && throttleMessages(txMessages)) {
//LogUtil.log("[bus] *DEFERRED* :: " + txMessages);
return;
}
else {
toSend.addAll(getDeferredToSend());
toSend.addAll(txMessages);
}
specialParms = Collections.emptyMap();
}
undeliveredMessages.addAll(toSend);
final String message = BusToolsCli.encodeMessages(toSend);
//LogUtil.log("[bus] toSend=" + toSend);
try {
txActive = true;
final long startTime = System.currentTimeMillis();
try {
sendPollingRequest(message, specialParms, new RemoteRequestCallback(startTime, toSend, txMessages));
}
catch (Exception e) {
e.printStackTrace();
for (final Message txM : txMessages) {
messageBus.callErrorHandler(txM, e);
}
LogUtil.log("exception: " + e.getMessage());
}
}
finally {
lastTx = System.currentTimeMillis();
txActive = false;
}
}
public void performPoll() {
Request request = null;
try {
final List<Message> toSend;
if (heldMessages.isEmpty()) {
toSend = Collections.emptyList();
}
else {
toSend = new ArrayList<Message>(getDeferredToSend());
}
request = sendPollingRequest(BusToolsCli.encodeMessages(toSend), Collections.<String, String>emptyMap(), receiveCommCallback);
}
catch (RequestTimeoutException e) {
receiveCommCallback.onError(null, e);
}
catch (Throwable t) {
if (messageBus.handleTransportError(new BusTransportError(request, t, -1, RetryInfo.NO_RETRY))) {
return;
}
DefaultErrorCallback.INSTANCE.error(null, t);
}
}
@Override
public Collection<Message> stop(final boolean stopAllCurrentRequests) {
receiveCommCallback.cancel();
try {
if (stopAllCurrentRequests) {
// Now stop all the in-flight XHRs
for (final RxInfo r : pendingRequests) {
r.getRequest().cancel();
}
pendingRequests.clear();
return new ArrayList<Message>(undeliveredMessages);
}
else {
return Collections.emptyList();
}
}
finally {
undeliveredMessages.clear();
}
}
private class NoPollRequestCallback extends LongPollRequestCallback {
@Override
public void schedule() {
}
@Override
public boolean canWait() {
return false;
}
}
private class ShortPollRequestCallback extends LongPollRequestCallback {
public ShortPollRequestCallback() {
}
@Override
public void schedule() {
new Timer() {
@Override
public void run() {
if (!canceled) {
performPoll();
}
}
}.schedule(POLL_FREQUENCY_MS);
}
@Override
public boolean canWait() {
return false;
}
}
@Override
public void handleProtocolExtension(final Message message) {
}
private class LongPollRequestCallback implements RequestCallback {
/**
* Subclasses MUST check this flag is still false before calling performPoll().
*/
protected boolean canceled = false;
@Override
public void onError(final Request request, final Throwable throwable) {
onError(request, throwable, -1);
}
public void onError(final Request request, final Throwable throwable, final int statusCode) {
final int retryDelay = Math.min((rxRetries * 1000) + 1, 10000);
final RetryInfo retryInfo = new RetryInfo(retryDelay, rxRetries);
final BusTransportError transportError = new BusTransportError(request, throwable, statusCode, retryInfo);
notifyDisconnected();
if (messageBus.handleTransportError(transportError)) {
return;
}
switch (statusCode) {
case 0:
case 1:
case 401:
break;
case 400: // happens when JBossAS is going down
case 404: // happens after errai app is undeployed
case 408: // request timeout--probably worth retrying
case 500: // we expect this may happen during restart of some non-JBoss servers
case 502: // bad gateway--could happen if long poll request was proxied to a down server
case 503: // temporary overload (probably on a proxy)
case 504: // gateway timeout--same possibilities as 502
LogUtil.log("attempting Rx reconnection -- attempt: " + (rxRetries + 1));
rxRetries++;
new Timer() {
@Override
public void run() {
performPoll();
}
}.schedule(retryDelay);
return;
default:
// polling error is probably unrecoverable; go to local-only mode
DefaultErrorCallback.INSTANCE.error(null, throwable);
messageBus.handleTransportError(transportError);
}
}
@Override
public void onResponseReceived(final Request request, final Response response) {
final int statusCode = response.getStatusCode();
if (statusCode != 200) {
switch (statusCode) {
case 300:
case 301:
case 302:
case 303:
case 304:
case 305:
case 307:
break;
case 401:
BusToolsCli.decodeToCallback(response.getText(), messageCallback);
break;
default:
onError(request,
new TransportIOException("unexpected response code: " + statusCode, statusCode, response
.getStatusText()), statusCode);
return;
}
}
notifyConnected();
BusToolsCli.decodeToCallback(response.getText(), messageCallback);
if (pendingRequests.isEmpty()) {
schedule();
}
}
public void schedule() {
if (canceled) {
return;
}
new Timer() {
@Override
public void run() {
performPoll();
}
}.schedule(1);
}
public void cancel() {
canceled = true;
}
public boolean canWait() {
return true;
}
}
/**
* Sends the given string oon the outbound communication channel (as a POST
* request to the server).
*
* @param payload
* The message to send. It is sent verbatim.
* @param callback
* The callback to receive success or error notification. Note that
* this callback IS NOT CALLED if the request is cancelled.
* @param extraParameters
* Extra paramets to include in the HTTP request (key is parameter name;
* value is parameter value).
*
* @throws com.google.gwt.http.client.RequestException
* if the request cannot be sent at all.
*/
public Request sendPollingRequest(
final String payload,
final Map<String, String> extraParameters,
final RequestCallback callback) throws RequestException {
// LogUtil.log("[bus] sendPollingRequest(" + payload + ")");
final String serviceEntryPoint;
final Map<String, String> parmsMap;
final boolean waitChannel;
boolean activeWaitChannel = false;
final Iterator<RxInfo> iterator = pendingRequests.iterator();
while (iterator.hasNext()) {
final RxInfo pendingRx = iterator.next();
if (pendingRx.getRequest().isPending() && pendingRx.isWaiting()) {
// LogUtil.log("[bus] ABORT SEND: " + pendingRx + " is waiting" );
// return null;
activeWaitChannel = true;
}
if (!pendingRx.getRequest().isPending()) {
iterator.remove();
}
}
if (!activeWaitChannel && receiveCommCallback.canWait() && !rxActive) {
parmsMap = new HashMap<String, String>(extraParameters);
parmsMap.put("wait", "1");
serviceEntryPoint = messageBus.getInServiceEntryPoint();
waitChannel = true;
}
else {
parmsMap = extraParameters;
serviceEntryPoint = messageBus.getOutServiceEntryPoint();
waitChannel = false;
}
rxActive = true;
final StringBuilder extraParmsString = new StringBuilder();
for (final Map.Entry<String, String> entry : parmsMap.entrySet()) {
extraParmsString.append("&").append(
URL.encodePathSegment(entry.getKey())).append("=").append(URL.encodePathSegment(entry.getValue())
);
}
final long latencyTime = System.currentTimeMillis();
final RequestBuilder builder = new RequestBuilder(
RequestBuilder.POST,
URL.encode(messageBus.getApplicationLocation(serviceEntryPoint)) + "?z=" + getNextRequestNumber()
+ "&clientId=" + URL.encodePathSegment(messageBus.getClientId()) + extraParmsString.toString()
);
builder.setHeader("Content-Type", "application/json; charset=utf-8");
final RxInfo rxInfo = new RxInfo(System.currentTimeMillis(), waitChannel);
try {
// LogUtil.log("[bus] TX: " + payload);
final Request request = builder.sendRequest(payload, new RequestCallback() {
@Override
public void onResponseReceived(final Request request, final Response response) {
if (!waitChannel) {
measuredLatency = (int) (System.currentTimeMillis() - latencyTime);
}
pendingRequests.remove(rxInfo);
callback.onResponseReceived(request, response);
rxNumber++;
rxActive = false;
}
@Override
public void onError(final Request request, final Throwable exception) {
pendingRequests.remove(rxInfo);
callback.onError(request, exception);
rxActive = false;
}
});
rxInfo.setRequest(request);
pendingRequests.add(rxInfo);
return request;
}
catch (RequestException e) {
pendingRequests.remove(rxInfo);
throw e;
}
}
public int getNextRequestNumber() {
if (txNumber == Integer.MAX_VALUE) {
txNumber = 0;
}
return txNumber++;
}
private int throttleOutgoing() {
return (int) (System.currentTimeMillis() - lastTx) - THROTTLE_TIME_MS;
}
private void notifyConnected() {
if (connectedTime == -1) {
connectedTime = System.currentTimeMillis();
}
if (messageBus.getState() == BusState.CONNECTION_INTERRUPTED)
messageBus.setState(BusState.CONNECTED);
rxRetries = 0;
}
private void notifyDisconnected() {
connectedTime = -1;
}
private static class RxInfo {
private Request request;
private final boolean waiting;
private final long time;
private RxInfo(long time, boolean waiting) {
this.time = time;
this.waiting = waiting;
}
public void setRequest(Request request) {
this.request = request;
}
public Request getRequest() {
return request;
}
public boolean isWaiting() {
return waiting;
}
public long getTime() {
return time;
}
}
@Override
public String toString() {
if (receiveCommCallback instanceof NoPollRequestCallback) {
return "No Polling";
}
else if (receiveCommCallback instanceof ShortPollRequestCallback) {
return "Short Polling";
}
else {
return "Long Polling";
}
}
@Override
public TransportStatistics getStatistics() {
return this;
}
@Override
public String getTransportDescription() {
return "HTTP " + toString();
}
@Override
public int getMessagesSent() {
return txNumber;
}
@Override
public int getMessagesReceived() {
return rxNumber;
}
@Override
public long getConnectedTime() {
return connectedTime;
}
@Override
public long getLastTransmissionTime() {
return lastTx;
}
@Override
public int getMeasuredLatency() {
return measuredLatency;
}
@Override
public boolean isFullDuplex() {
return false;
}
@Override
public String getRxEndpoint() {
return messageBus.getInServiceEntryPoint();
}
@Override
public String getTxEndpoint() {
return messageBus.getOutServiceEntryPoint();
}
@Override
public String getUnsupportedDescription() {
return UNSUPPORTED_MESSAGE_NO_SERVER_SUPPORT;
}
@Override
public int getPendingMessages() {
return heldMessages.size();
}
private class RemoteRequestCallback implements RequestCallback {
private final long startTime;
private final List<Message> toSend;
private final List<Message> txMessages;
int statusCode;
public RemoteRequestCallback(long startTime, List<Message> toSend, List<Message> txMessages) {
this.startTime = startTime;
this.toSend = toSend;
this.txMessages = txMessages;
statusCode = 0;
}
@Override
public void onResponseReceived(final Request request, final Response response) {
txActive = false;
statusCode = response.getStatusCode();
switch (statusCode) {
case 401:
if (System.currentTimeMillis() - startTime > 2000) {
undeliveredMessages.removeAll(toSend);
}
try {
if (BusToolsCli.decodeToCallback(response.getText(), messageCallback)) {
break;
}
}
catch (Throwable e) {
// fall through.
}
case 0:
case 1:
case 400: // happens when JBossAS is going down
case 404: // happens after errai app is undeployed
case 408: // request timeout--probably worth retrying
case 500: // we expect this may happen during restart of some non-JBoss servers
case 502: // bad gateway--could happen if long poll request was proxied to a down server
case 503: // temporary overload (probably on a proxy)
case 504: // gateway timeout--same possibilities as 502
{
final int retryDelay = Math.min((txRetries * 1000) + 1, 10000);
final RetryInfo retryInfo = new RetryInfo(retryDelay, txRetries);
final BusTransportError transportError = new BusTransportError(request, null, statusCode, retryInfo);
notifyDisconnected();
if (messageBus.handleTransportError(transportError)) {
return;
}
LogUtil.log("attempting Tx reconnection -- attempt: " + (txRetries + 1));
txRetries++;
new Timer() {
@Override
public void run() {
undeliveredMessages.removeAll(toSend);
transmit(toSend);
}
}.schedule(retryDelay);
return;
}
case 200:
notifyConnected();
undeliveredMessages.removeAll(toSend);
schedulePolling();
break;
default: {
final BusTransportError transportError = new BusTransportError(request, null, statusCode, RetryInfo.NO_RETRY);
if (messageBus.handleTransportError(transportError)) {
return;
}
// polling error is probably unrecoverable; go to local-only mode
DefaultErrorCallback.INSTANCE.error(null, null);
messageBus.handleTransportError(transportError);
}
}
BusToolsCli.decodeToCallback(response.getText(), messageCallback);
}
@Override
public void onError(final Request request, final Throwable exception) {
txActive = false;
notifyDisconnected();
messageBus.handleTransportError(new BusTransportError(request, exception, statusCode, RetryInfo.NO_RETRY));
for (final Message txM : txMessages) {
if (txM.getErrorCallback() == null || txM.getErrorCallback().error(txM, exception)) {
LogUtil.log("failed to communicate with remote bus: " + exception);
}
}
schedulePolling();
}
private void schedulePolling() {
if (pendingRequests.isEmpty()) {
new Timer() {
@Override
public void run() {
performPoll();
}
}.schedule(1);
}
}
}
@Override
public void close() {
stop(true);
configured = false;
}
}