Java tutorial
/** * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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.waveprotocol.wave.federation.xmpp; import com.google.common.base.Preconditions; import com.google.common.collect.ImmutableList; import com.google.common.collect.Lists; import com.google.inject.Inject; import com.google.inject.name.Named; import com.google.protobuf.ByteString; import org.apache.commons.codec.binary.Base64; import org.dom4j.Attribute; import org.dom4j.Element; import org.waveprotocol.wave.federation.FederationErrors; import org.waveprotocol.wave.federation.FederationRemoteBridge; import org.waveprotocol.wave.federation.FederationSettings; import org.waveprotocol.wave.federation.WaveletFederationListener; import org.waveprotocol.wave.federation.WaveletFederationProvider; import org.waveprotocol.wave.federation.FederationErrorProto.FederationError; import org.waveprotocol.wave.federation.Proto.ProtocolHashedVersion; import org.waveprotocol.wave.federation.Proto.ProtocolSignedDelta; import org.waveprotocol.wave.federation.Proto.ProtocolSignerInfo; import org.waveprotocol.wave.federation.xmpp.XmppUtil.UnknownSignerType; import org.waveprotocol.wave.model.id.WaveletName; import org.waveprotocol.wave.model.id.URIEncoderDecoder.EncodingException; import org.xmpp.packet.IQ; import org.xmpp.packet.Message; import org.xmpp.packet.Packet; import java.util.List; import java.util.concurrent.atomic.AtomicInteger; import java.util.logging.Logger; /** * Remote implementation. Receives submit and history requests from the local * wave server and sends them to a remote wave server Host, and also receives * update messages from a remote wave server Host and sends them to the local * wave server. */ public class XmppFederationRemote implements WaveletFederationProvider { private static final Logger LOG = Logger.getLogger(XmppFederationRemote.class.getCanonicalName()); // Timeout for outstanding provider calls sent over XMPP. private static final int XMPP_PROVIDER_TIMEOUT = 30; private final WaveletFederationListener.Factory updatesListenerFactory; private final XmppDisco disco; private final String jid; private XmppManager manager = null; /** * Constructor. Note that {@link #setManager} must be called before this class * is ready to use. * * @param updatesListenerFactory used to communicate back to the local wave * server when an update arrives. */ @Inject public XmppFederationRemote(@FederationRemoteBridge WaveletFederationListener.Factory updatesListenerFactory, XmppDisco disco, @Named(FederationSettings.XMPP_JID) String jid) { this.updatesListenerFactory = updatesListenerFactory; this.disco = disco; this.jid = jid; } /** * Set the manager instance for this class. Must be invoked before any other * methods are used. */ public void setManager(XmppManager manager) { this.manager = manager; } /** * Request submission of signed delta. This is part of the Federation Remote * interface - sends a submit request on behalf of the wave server. Part of * the WaveletFederationProvider interface. * * @param waveletName name of wavelet. * @param signedDelta delta signed by the submitting wave server. * @param listener callback for the result of the submit. */ @Override public void submitRequest(final WaveletName waveletName, final ProtocolSignedDelta signedDelta, final SubmitResultListener listener) { final IQ submitIq = new IQ(IQ.Type.set); submitIq.setID(XmppUtil.generateUniqueId()); LOG.info("Submitting delta to remote server, wavelet " + waveletName); submitIq.setFrom(jid); Element pubsub = submitIq.setChildElement("pubsub", XmppNamespace.NAMESPACE_PUBSUB); Element publish = pubsub.addElement("publish"); publish.addAttribute("node", "wavelet"); Element submitRequest = publish.addElement("item").addElement("submit-request", XmppNamespace.NAMESPACE_WAVE_SERVER); Element deltaElement = submitRequest.addElement("delta"); deltaElement.addCDATA(Base64Util.encode(signedDelta.toByteArray())); try { deltaElement.addAttribute("wavelet-name", XmppUtil.waveletNameCodec.waveletNameToURI(waveletName)); } catch (EncodingException e) { listener.onFailure(FederationErrors.badRequest("Couldn't encode wavelet name " + waveletName)); return; } final PacketCallback callback = new PacketCallback() { @Override public void error(FederationError error) { listener.onFailure(error); } @Override public void run(Packet packet) { processSubmitResponse(packet, listener); } }; disco.discoverRemoteJid(waveletName.waveletId.getDomain(), new SuccessFailCallback<String, String>() { @Override public void onSuccess(String remoteJid) { Preconditions.checkNotNull(remoteJid); submitIq.setTo(remoteJid); manager.send(submitIq, callback, XMPP_PROVIDER_TIMEOUT); } @Override public void onFailure(String errorMessage) { // TODO(thorogood): Broken, Disco should return the error (and it // should be timeout/etc) listener.onFailure(FederationErrors.badRequest( "No such wave server " + waveletName.waveletId.getDomain() + ": " + errorMessage)); } }); } /** * Retrieve delta history for the given wavelet. <p/> Part of the * WaveletFederationProvider interface. * * @param waveletName name of wavelet. * @param domain the remote Federation Host * @param startVersion beginning of range (inclusive), minimum 0. * @param endVersion end of range (exclusive). * @param lengthLimit estimated size, in bytes, as an upper limit on the * amount of data returned. * @param listener callback for the result. */ public void requestHistory(final WaveletName waveletName, final String domain, ProtocolHashedVersion startVersion, ProtocolHashedVersion endVersion, long lengthLimit, final WaveletFederationProvider.HistoryResponseListener listener) { final IQ submitIq = new IQ(IQ.Type.get); submitIq.setID(XmppUtil.generateUniqueId()); LOG.info("Getting history from remote server, wavelet " + waveletName + " version " + startVersion + " (inc) through " + endVersion + " (ex)"); submitIq.setFrom(jid); Element pubsub = submitIq.setChildElement("pubsub", XmppNamespace.NAMESPACE_PUBSUB); Element items = pubsub.addElement("items"); items.addAttribute("node", "wavelet"); Element historyDelta = items.addElement("delta-history", XmppNamespace.NAMESPACE_WAVE_SERVER); historyDelta.addAttribute("start-version", Long.toString(startVersion.getVersion())); historyDelta.addAttribute("start-version-hash", Base64Util.encode(startVersion.getHistoryHash())); historyDelta.addAttribute("end-version", Long.toString(endVersion.getVersion())); historyDelta.addAttribute("end-version-hash", Base64Util.encode(endVersion.getHistoryHash())); if (lengthLimit > 0) { historyDelta.addAttribute("response-length-limit", Long.toString(lengthLimit)); } try { historyDelta.addAttribute("wavelet-name", XmppUtil.waveletNameCodec.waveletNameToURI(waveletName)); } catch (EncodingException e) { listener.onFailure(FederationErrors.badRequest("Couldn't encode wavelet name " + waveletName)); return; } final PacketCallback callback = new PacketCallback() { public void error(FederationError error) { listener.onFailure(error); } @Override public void run(Packet packet) { processHistoryResponse(packet, listener); } }; disco.discoverRemoteJid(domain, new SuccessFailCallback<String, String>() { @Override public void onSuccess(String remoteJid) { Preconditions.checkNotNull(remoteJid); submitIq.setTo(remoteJid); manager.send(submitIq, callback, XMPP_PROVIDER_TIMEOUT); } @Override public void onFailure(String errorMessage) { listener.onFailure( FederationErrors.badRequest("No such wave server " + domain + ": " + errorMessage)); } }); } @Override public void getDeltaSignerInfo(ByteString signerId, WaveletName waveletName, ProtocolHashedVersion deltaEndVersion, final DeltaSignerInfoResponseListener listener) { final IQ getSignerIq = new IQ(IQ.Type.get); getSignerIq.setID(XmppUtil.generateUniqueId()); getSignerIq.setFrom(jid); // Extract domain from waveletId final String remoteDomain = waveletName.waveletId.getDomain(); Element pubsub = getSignerIq.setChildElement("pubsub", XmppNamespace.NAMESPACE_PUBSUB); Element items = pubsub.addElement("items"); items.addAttribute("node", "signer"); // TODO: should allow multiple requests in the same packet Element signerRequest = items.addElement("signer-request", XmppNamespace.NAMESPACE_WAVE_SERVER); signerRequest.addAttribute("signer-id", Base64Util.encode(signerId)); signerRequest.addAttribute("history-hash", Base64Util.encode(deltaEndVersion.getHistoryHash())); signerRequest.addAttribute("version", String.valueOf(deltaEndVersion.getVersion())); try { signerRequest.addAttribute("wavelet-name", XmppUtil.waveletNameCodec.waveletNameToURI(waveletName)); } catch (EncodingException e) { listener.onFailure(FederationErrors.badRequest("Couldn't encode wavelet name " + waveletName)); return; } final PacketCallback callback = new PacketCallback() { @Override public void error(FederationError error) { listener.onFailure(error); } @Override public void run(Packet packet) { processGetSignerResponse(packet, listener); } }; disco.discoverRemoteJid(remoteDomain, new SuccessFailCallback<String, String>() { @Override public void onSuccess(String remoteJid) { Preconditions.checkNotNull(remoteJid); getSignerIq.setTo(remoteJid); manager.send(getSignerIq, callback, XMPP_PROVIDER_TIMEOUT); } @Override public void onFailure(String errorMessage) { listener.onFailure( FederationErrors.badRequest("No such wave server " + remoteDomain + ": " + errorMessage)); } }); } @Override public void postSignerInfo(final String remoteDomain, ProtocolSignerInfo signerInfo, final WaveletFederationProvider.PostSignerInfoResponseListener listener) { final IQ request = new IQ(IQ.Type.set); request.setID(XmppUtil.generateUniqueId()); request.setFrom(jid); Element pubsub = request.setChildElement("pubsub", XmppNamespace.NAMESPACE_PUBSUB); Element publish = pubsub.addElement("publish"); publish.addAttribute("node", "signer"); XmppUtil.protocolSignerInfoToXml(signerInfo, publish.addElement("item")); final PacketCallback callback = new PacketCallback() { @Override public void error(FederationError error) { listener.onFailure(error); } @Override public void run(Packet packet) { processPostSignerResponse(packet, listener); } }; disco.discoverRemoteJid(remoteDomain, new SuccessFailCallback<String, String>() { @Override public void onSuccess(String remoteJid) { Preconditions.checkNotNull(remoteJid); request.setTo(remoteJid); manager.send(request, callback, XMPP_PROVIDER_TIMEOUT); } @Override public void onFailure(String errorMessage) { listener.onFailure( FederationErrors.badRequest("No such wave server " + remoteDomain + ": " + errorMessage)); } }); } /** * Handles a wavelet update message from a foreign Federation Host. Passes the * message to the local waveserver (synchronously) and replies. * * @param updateMessage the incoming XMPP message. * @param responseCallback response callback for acks and errors */ public void update(final Message updateMessage, final PacketCallback responseCallback) { final Element receiptRequested = updateMessage.getChildElement("request", XmppNamespace.NAMESPACE_XMPP_RECEIPTS); // Check existence of <event> Element event = updateMessage.getChildElement("event", XmppNamespace.NAMESPACE_PUBSUB_EVENT); if (event == null) { responseCallback.error(FederationErrors.badRequest("Event element missing from message")); return; } // Check existence of <items> within <event> Element items = event.element("items"); if (items == null) { responseCallback.error(FederationErrors.badRequest("Items element missing from update message")); return; } // Complain if no items have been included. List<Element> elements = XmppUtil.toSafeElementList(items.elements("item")); if (elements.isEmpty()) { responseCallback.error(FederationErrors.badRequest("No items included")); return; } // Create a callback latch counter and corresponding countDown runnable. // When the latch reaches zero, send receipt (if it was requested). final AtomicInteger callbackCount = new AtomicInteger(1); final Runnable countDown = new Runnable() { @Override public void run() { if (callbackCount.decrementAndGet() == 0 && receiptRequested != null) { Message response = XmppUtil.createResponseMessage(updateMessage); response.addChildElement("received", XmppNamespace.NAMESPACE_XMPP_RECEIPTS); responseCallback.run(response); } } }; WaveletFederationListener.WaveletUpdateCallback callback = new WaveletFederationListener.WaveletUpdateCallback() { @Override public void onSuccess() { countDown.run(); } @Override public void onFailure(FederationError error) { // Note that we don't propogate the error, we just ack the stanza // and continue. // TODO(thorogood): We may want to rate-limit misbehaving servers // that are sending us invalid/malicious data. LOG.warning("Incoming XMPP waveletUpdate failure: " + error); countDown.run(); } }; // We must call callback once on every iteration to ensure that we send // response if receiptRequested != null. for (Element item : elements) { Element waveletUpdate = item.element("wavelet-update"); if (waveletUpdate == null) { callback.onFailure(FederationErrors .badRequest("wavelet-update element missing from message: " + updateMessage)); continue; } final WaveletName waveletName; try { waveletName = XmppUtil.waveletNameCodec .uriToWaveletName(waveletUpdate.attributeValue("wavelet-name")); } catch (EncodingException e) { callback.onFailure(FederationErrors.badRequest( "Couldn't decode wavelet name: " + waveletUpdate.attributeValue("wavelet-name"))); continue; } WaveletFederationListener listener = updatesListenerFactory .listenerForDomain(waveletName.waveletId.getDomain()); // Submit all applied deltas to the domain-focused listener. ImmutableList.Builder<ByteString> builder = ImmutableList.builder(); for (Element appliedDeltaElement : XmppUtil .toSafeElementList(waveletUpdate.elements("applied-delta"))) { builder.add(Base64Util.decode(appliedDeltaElement.getText())); } ImmutableList<ByteString> deltas = builder.build(); if (!deltas.isEmpty()) { callbackCount.incrementAndGet(); // Increment required callbacks. listener.waveletDeltaUpdate(waveletName, deltas, callback); } // Optionally submit any received last committed notice. Element commitNoticeElement = waveletUpdate.element("commit-notice"); if (commitNoticeElement != null) { ProtocolHashedVersion version = ProtocolHashedVersion.newBuilder() .setHistoryHash(Base64Util.decode(commitNoticeElement.attributeValue("history-hash"))) .setVersion(Long.parseLong(commitNoticeElement.attributeValue("version"))).build(); callbackCount.incrementAndGet(); // Increment required callbacks. listener.waveletCommitUpdate(waveletName, version, callback); } } // Release sentinel so that 'expected' callbacks from the WS don't invoke // sending a receipt. countDown.run(); } /** * Parses the response to a submitRequest and passes the result to the correct * wave server. * * @param result the XMPP Packet * @param listener the listener to invoke with the response. */ private void processSubmitResponse(Packet result, SubmitResultListener listener) { Element publish = null; Element item = null; Element submitResponse = null; Element hashedVersionElement = null; Element pubsub = ((IQ) result).getChildElement(); if (pubsub != null) { publish = pubsub.element("publish"); if (publish != null) { item = publish.element("item"); if (item != null) { submitResponse = item.element("submit-response"); if (submitResponse != null) { hashedVersionElement = submitResponse.element("hashed-version"); } } } } if (pubsub == null || publish == null || item == null || submitResponse == null || hashedVersionElement == null || hashedVersionElement.attribute("history-hash") == null || hashedVersionElement.attribute("version") == null || submitResponse.attribute("application-timestamp") == null || submitResponse.attribute("operations-applied") == null) { LOG.severe("Unexpected submitResponse to submit request: " + result); listener.onFailure(FederationErrors.badRequest("Invalid submitResponse: " + result)); return; } ProtocolHashedVersion.Builder hashedVersion = ProtocolHashedVersion.newBuilder(); hashedVersion.setHistoryHash(Base64Util.decode(hashedVersionElement.attributeValue("history-hash"))); hashedVersion.setVersion(Long.parseLong(hashedVersionElement.attributeValue("version"))); long applicationTimestamp = Long.parseLong(submitResponse.attributeValue("application-timestamp")); int operationsApplied = Integer.parseInt(submitResponse.attributeValue("operations-applied")); listener.onSuccess(operationsApplied, hashedVersion.build(), applicationTimestamp); } /** * Parses a response to a history request and passes the result to the wave * server. * * @param historyResponse the XMPP packet * @param listener interface to the wave server */ @SuppressWarnings("unchecked") private void processHistoryResponse(Packet historyResponse, WaveletFederationProvider.HistoryResponseListener listener) { Element pubsubResponse = historyResponse.getElement().element("pubsub"); Element items = pubsubResponse.element("items"); long versionTruncatedAt = -1; long lastCommittedVersion = -1; List<ByteString> deltaList = Lists.newArrayList(); if (items != null) { for (Element itemElement : (List<Element>) items.elements()) { for (Element element : (List<Element>) itemElement.elements()) { String elementName = element.getQName().getName(); if (elementName.equals("applied-delta")) { String deltaBody = element.getText(); deltaList.add(ByteString.copyFrom(Base64.decodeBase64(deltaBody.getBytes()))); } else if (elementName.equals("commit-notice")) { Attribute commitVersion = element.attribute("version"); if (commitVersion != null) { try { lastCommittedVersion = Long.parseLong(commitVersion.getValue()); } catch (NumberFormatException e) { lastCommittedVersion = -1; } } } else if (elementName.equals("history-truncated")) { Attribute truncVersion = element.attribute("version"); if (truncVersion != null) { try { versionTruncatedAt = Long.parseLong(truncVersion.getValue()); } catch (NumberFormatException e) { versionTruncatedAt = -1; } } } else { listener.onFailure(FederationErrors.badRequest("Bad response packet: " + historyResponse)); } } } } else { listener.onFailure(FederationErrors.badRequest("Bad response packet: " + historyResponse)); } final ProtocolHashedVersion lastCommitted; if (lastCommittedVersion > -1) { // TODO(thorogood): fedone doesn't send a history hash, and it's arguable // that it's even sane to include it. // Can't set it to null - NPE lastCommitted = ProtocolHashedVersion.newBuilder().setVersion(lastCommittedVersion) .setHistoryHash(ByteString.EMPTY).build(); } else { lastCommitted = null; } listener.onSuccess(deltaList, lastCommitted, versionTruncatedAt); } /** * Parses a GetSigner response, passes result to the waveserver. * * @param packet the response packet * @param listener the interface to the wave server */ private void processGetSignerResponse(Packet packet, DeltaSignerInfoResponseListener listener) { IQ response = (IQ) packet; Element items = response.getChildElement().element("items"); Element signature = items.element("signature"); if (signature == null) { LOG.severe("Empty getDeltaSignerRequest response: " + response); listener.onFailure(FederationErrors.badRequest("Bad getDeltaSignatureRequest response")); return; } String domain = signature.attributeValue("domain"); String hashName = signature.attributeValue("algorithm"); if (domain == null || hashName == null || signature.element("certificate") == null) { LOG.severe("Bad getDeltaSignerRequest response: " + response); listener.onFailure(FederationErrors.badRequest("Bad getDeltaSignatureRequest response")); return; } ProtocolSignerInfo signer; try { signer = XmppUtil.xmlToProtocolSignerInfo(signature); } catch (UnknownSignerType e) { listener.onFailure(FederationErrors.badRequest(e.toString())); return; } listener.onSuccess(signer); } /** * Parses a response to a PostSigner request, passes result to wave server. * * @param packet the response XMPP packet * @param listener the listener to invoke */ private void processPostSignerResponse(Packet packet, WaveletFederationProvider.PostSignerInfoResponseListener listener) { IQ response = (IQ) packet; Element pubsub = response.getChildElement(); Element item = pubsub.element("publish").element("item"); if (item.element("signature-response") != null) { listener.onSuccess(); } else { listener.onFailure(FederationErrors.badRequest("No valid response")); } } }