EntityCapsManager.java
/**
*
* Copyright © 2009 Jonas Ådahl, 2011-2022 Florian Schmaus
*
* 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.jivesoftware.smackx.caps;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Queue;
import java.util.Set;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.WeakHashMap;
import java.util.concurrent.ConcurrentLinkedQueue;
import org.jivesoftware.smack.ConnectionCreationListener;
import org.jivesoftware.smack.ConnectionListener;
import org.jivesoftware.smack.Manager;
import org.jivesoftware.smack.SmackConfiguration;
import org.jivesoftware.smack.SmackException.NoResponseException;
import org.jivesoftware.smack.SmackException.NotConnectedException;
import org.jivesoftware.smack.StanzaListener;
import org.jivesoftware.smack.XMPPConnection;
import org.jivesoftware.smack.XMPPConnectionRegistry;
import org.jivesoftware.smack.XMPPException.XMPPErrorException;
import org.jivesoftware.smack.filter.AndFilter;
import org.jivesoftware.smack.filter.PresenceTypeFilter;
import org.jivesoftware.smack.filter.StanzaExtensionFilter;
import org.jivesoftware.smack.filter.StanzaFilter;
import org.jivesoftware.smack.filter.StanzaTypeFilter;
import org.jivesoftware.smack.packet.Presence;
import org.jivesoftware.smack.packet.PresenceBuilder;
import org.jivesoftware.smack.packet.Stanza;
import org.jivesoftware.smack.roster.AbstractPresenceEventListener;
import org.jivesoftware.smack.roster.Roster;
import org.jivesoftware.smack.util.StringUtils;
import org.jivesoftware.smack.util.stringencoder.Base64;
import org.jivesoftware.smackx.caps.cache.EntityCapsPersistentCache;
import org.jivesoftware.smackx.caps.packet.CapsExtension;
import org.jivesoftware.smackx.disco.AbstractNodeInformationProvider;
import org.jivesoftware.smackx.disco.DiscoInfoLookupShortcutMechanism;
import org.jivesoftware.smackx.disco.EntityCapabilitiesChangedListener;
import org.jivesoftware.smackx.disco.ServiceDiscoveryManager;
import org.jivesoftware.smackx.disco.packet.DiscoverInfo;
import org.jivesoftware.smackx.disco.packet.DiscoverInfo.Feature;
import org.jivesoftware.smackx.disco.packet.DiscoverInfo.Identity;
import org.jivesoftware.smackx.disco.packet.DiscoverInfoBuilder;
import org.jivesoftware.smackx.disco.packet.DiscoverInfoView;
import org.jivesoftware.smackx.xdata.FormField;
import org.jivesoftware.smackx.xdata.packet.DataForm;
import org.jxmpp.jid.DomainBareJid;
import org.jxmpp.jid.FullJid;
import org.jxmpp.jid.Jid;
import org.jxmpp.util.cache.LruCache;
/**
* Manages own and others Entity Capabilities (XEP-0115).
* <p>
* Entity Capabilities is an XMPP extension which, in order to minimize network impact, caches the capabilities of
* remote XMPP entities. Those capabilities are determine with the help of the Service Discovery Protocol
* (<a href="https://xmpp.org/extensions/xep-0030.html">XEP-0030</a>, {@link ServiceDiscoveryManager}).
* </p>
*
* <h2>Usage</h2>
* <p>
* Entity Capabilities work silently in the background when enabled. If the remote XMPP entity does not support XEP-0115
* but XEP-0030 then XEP-0030 mechanisms are transparently used.
* </p>
* <p>
* The caches used by Smack for Entity Capabilities is non-persisent per default. However, it is is also possible to set
* a persistent Entity Capabilities cache, which is recommended.
* </p>
* <h2>Examples</h2>
*
* <h3>Enable Entity Capabilities</h3>
* <pre>{@code
* // Get an instance of entity caps manager for the specified connection
* EntityCapsManager mgr = EntityCapsManager.getInstanceFor(connection);
* // Enable entity capabilities
* mgr.enableEntityCaps();
* }</pre>
*
* <h3>Configure a persistent cache for Entity Capabilities</h3>
* <pre>{@code
* // Get an instance of entity caps manager for the specified connection
* EntityCapsManager mgr = EntityCapsManager.getInstanceFor(connection);
* // Create an cache, see smackx.entitycaps.cache for pre-defined cache implementations
* EntityCapsPersistentCache cache = new SimpleDirectoryPersistentCache(new File("/foo/cachedir"));
* // Set the cache
* mgr.setPersistentCache(cache);
* }</pre>
*
* @author Florian Schmaus
* @see <a href="http://www.xmpp.org/extensions/xep-0115.html">XEP-0115: Entity Capabilities</a>
*/
public final class EntityCapsManager extends Manager {
public static final String NAMESPACE = CapsExtension.NAMESPACE;
public static final String ELEMENT = CapsExtension.ELEMENT;
private static final Map<String, MessageDigest> SUPPORTED_HASHES = new HashMap<String, MessageDigest>();
/**
* The default hash. Currently 'sha-1'.
*/
private static final String DEFAULT_HASH = StringUtils.SHA1;
private static String DEFAULT_ENTITY_NODE = SmackConfiguration.SMACK_URL_STRING;
static EntityCapsPersistentCache persistentCache;
private static boolean autoEnableEntityCaps = true;
private static final Map<XMPPConnection, EntityCapsManager> instances = new WeakHashMap<>();
private static final StanzaFilter PRESENCES_WITH_CAPS = new AndFilter(new StanzaTypeFilter(Presence.class), new StanzaExtensionFilter(
ELEMENT, NAMESPACE));
/**
* Map of "node + '#' + hash" to DiscoverInfo data
*/
static final LruCache<String, DiscoverInfo> CAPS_CACHE = new LruCache<>(1000);
/**
* Map of Full JID -> DiscoverInfo/null. In case of c2s connection the
* key is formed as user@server/resource (resource is required) In case of
* link-local connection the key is formed as user@host (no resource) In
* case of a server or component the key is formed as domain
*/
static final LruCache<Jid, NodeVerHash> JID_TO_NODEVER_CACHE = new LruCache<>(10000);
static {
XMPPConnectionRegistry.addConnectionCreationListener(new ConnectionCreationListener() {
@Override
public void connectionCreated(XMPPConnection connection) {
getInstanceFor(connection);
}
});
try {
MessageDigest sha1MessageDigest = MessageDigest.getInstance(DEFAULT_HASH);
SUPPORTED_HASHES.put(DEFAULT_HASH, sha1MessageDigest);
} catch (NoSuchAlgorithmException e) {
// Ignore
}
ServiceDiscoveryManager.addDiscoInfoLookupShortcutMechanism(new DiscoInfoLookupShortcutMechanism("XEP-0115: Entity Capabilities", 100) {
@Override
public DiscoverInfo getDiscoverInfoByUser(ServiceDiscoveryManager serviceDiscoveryManager, Jid jid) {
DiscoverInfo info = EntityCapsManager.getDiscoverInfoByUser(jid);
if (info != null) {
return info;
}
NodeVerHash nodeVerHash = getNodeVerHashByJid(jid);
if (nodeVerHash == null) {
return null;
}
try {
info = serviceDiscoveryManager.discoverInfo(jid, nodeVerHash.getNodeVer());
} catch (NoResponseException | XMPPErrorException | NotConnectedException | InterruptedException e) {
// TODO log
return null;
}
if (verifyDiscoverInfoVersion(nodeVerHash.getVer(), nodeVerHash.getHash(), info)) {
addDiscoverInfoByNode(nodeVerHash.getNodeVer(), info);
} else {
// TODO log
}
return info;
}
});
}
/**
* Set the default entity node that will be used for new EntityCapsManagers.
*
* @param entityNode TODO javadoc me please
*/
public static void setDefaultEntityNode(String entityNode) {
DEFAULT_ENTITY_NODE = entityNode;
}
/**
* Add DiscoverInfo to the database.
*
* @param nodeVer TODO javadoc me please
* The node and verification String (e.g.
* "http://psi-im.org#q07IKJEyjvHSyhy//CH0CxmKi8w=").
* @param info TODO javadoc me please
* DiscoverInfo for the specified node.
*/
static void addDiscoverInfoByNode(String nodeVer, DiscoverInfo info) {
CAPS_CACHE.put(nodeVer, info);
if (persistentCache != null)
persistentCache.addDiscoverInfoByNodePersistent(nodeVer, info);
}
/**
* Get the Node version (node#ver) of a JID. Returns a String or null if
* EntiyCapsManager does not have any information.
*
* @param jid TODO javadoc me please
* the user (Full JID)
* @return the node version (node#ver) or null
*/
public static String getNodeVersionByJid(Jid jid) {
NodeVerHash nvh = JID_TO_NODEVER_CACHE.lookup(jid);
if (nvh != null) {
return nvh.nodeVer;
} else {
return null;
}
}
public static NodeVerHash getNodeVerHashByJid(Jid jid) {
return JID_TO_NODEVER_CACHE.lookup(jid);
}
/**
* Get the discover info given a user name. The discover info is returned if
* the user has a node#ver associated with it and the node#ver has a
* discover info associated with it.
*
* @param user TODO javadoc me please
* user name (Full JID)
* @return the discovered info
*/
public static DiscoverInfo getDiscoverInfoByUser(Jid user) {
NodeVerHash nvh = JID_TO_NODEVER_CACHE.lookup(user);
if (nvh == null)
return null;
return getDiscoveryInfoByNodeVer(nvh.nodeVer);
}
/**
* Retrieve DiscoverInfo for a specific node.
*
* @param nodeVer TODO javadoc me please
* The node name (e.g.
* "http://psi-im.org#q07IKJEyjvHSyhy//CH0CxmKi8w=").
* @return The corresponding DiscoverInfo or null if none is known.
*/
public static DiscoverInfo getDiscoveryInfoByNodeVer(String nodeVer) {
DiscoverInfo info = CAPS_CACHE.lookup(nodeVer);
// If it was not in CAPS_CACHE, try to retrieve the information from persistentCache
if (info == null && persistentCache != null) {
info = persistentCache.lookup(nodeVer);
// Promote the information to CAPS_CACHE if one was found
if (info != null) {
CAPS_CACHE.put(nodeVer, info);
}
}
// If we were able to retrieve information from one of the caches, copy it before returning
if (info != null)
info = new DiscoverInfo(info);
return info;
}
/**
* Set the persistent cache implementation.
*
* @param cache TODO javadoc me please
*/
public static void setPersistentCache(EntityCapsPersistentCache cache) {
persistentCache = cache;
}
/**
* Sets the maximum cache sizes.
*
* @param maxJidToNodeVerSize TODO javadoc me please
* @param maxCapsCacheSize TODO javadoc me please
*/
public static void setMaxsCacheSizes(int maxJidToNodeVerSize, int maxCapsCacheSize) {
JID_TO_NODEVER_CACHE.setMaxCacheSize(maxJidToNodeVerSize);
CAPS_CACHE.setMaxCacheSize(maxCapsCacheSize);
}
/**
* Clears the memory cache.
*/
public static void clearMemoryCache() {
JID_TO_NODEVER_CACHE.clear();
CAPS_CACHE.clear();
}
private static void addCapsExtensionInfo(Jid from, CapsExtension capsExtension) {
String capsExtensionHash = capsExtension.getHash();
String hashInUppercase = capsExtensionHash.toUpperCase(Locale.US);
// SUPPORTED_HASHES uses the format of MessageDigest, which is uppercase, e.g. "SHA-1" instead of "sha-1"
if (!SUPPORTED_HASHES.containsKey(hashInUppercase))
return;
String hash = capsExtensionHash.toLowerCase(Locale.US);
String node = capsExtension.getNode();
String ver = capsExtension.getVer();
JID_TO_NODEVER_CACHE.put(from, new NodeVerHash(node, ver, hash));
}
private final Queue<CapsVersionAndHash> lastLocalCapsVersions = new ConcurrentLinkedQueue<>();
private final ServiceDiscoveryManager sdm;
private boolean entityCapsEnabled;
private CapsVersionAndHash currentCapsVersion;
/**
* The entity node String used by this EntityCapsManager instance.
*/
private String entityNode = DEFAULT_ENTITY_NODE;
// Intercept presence packages and add caps data when intended.
// XEP-0115 specifies that a client SHOULD include entity capabilities
// with every presence notification it sends.
private void addCapsExtension(PresenceBuilder presenceBuilder) {
final CapsVersionAndHash capsVersionAndHash = getCapsVersionAndHash();
if (capsVersionAndHash == null) {
return;
}
CapsExtension caps = new CapsExtension(entityNode, capsVersionAndHash.version, capsVersionAndHash.hash);
presenceBuilder.overrideExtension(caps);
}
private EntityCapsManager(XMPPConnection connection) {
super(connection);
this.sdm = ServiceDiscoveryManager.getInstanceFor(connection);
instances.put(connection, this);
connection.addConnectionListener(new ConnectionListener() {
@Override
public void connected(XMPPConnection connection) {
// It's not clear when a server would report the caps stream
// feature, so we try to process it after we are connected and
// once after we are authenticated.
processCapsStreamFeatureIfAvailable(connection);
}
@Override
public void authenticated(XMPPConnection connection, boolean resumed) {
// It's not clear when a server would report the caps stream
// feature, so we try to process it after we are connected and
// once after we are authenticated.
processCapsStreamFeatureIfAvailable(connection);
}
private void processCapsStreamFeatureIfAvailable(XMPPConnection connection) {
CapsExtension capsExtension = connection.getFeature(
CapsExtension.class);
if (capsExtension == null) {
return;
}
DomainBareJid from = connection.getXMPPServiceDomain();
addCapsExtensionInfo(from, capsExtension);
}
});
if (autoEnableEntityCaps)
enableEntityCaps();
// Note that this is a *synchronous* stanza listener to avoid unnecessary feature lookups. If this were to be an
// asynchronous listener, then it would be possible that the entity caps information was not processed when the
// features of entity are looked up. See SMACK-937.
connection.addStanzaListener(new StanzaListener() {
// Listen for remote presence stanzas with the caps extension
// If we receive such a stanza, record the JID and nodeVer
@Override
public void processStanza(Stanza packet) {
if (!entityCapsEnabled())
return;
CapsExtension capsExtension = CapsExtension.from(packet);
Jid from = packet.getFrom();
addCapsExtensionInfo(from, capsExtension);
}
}, PRESENCES_WITH_CAPS);
Roster.getInstanceFor(connection).addPresenceEventListener(new AbstractPresenceEventListener() {
@Override
public void presenceUnavailable(FullJid from, Presence presence) {
JID_TO_NODEVER_CACHE.remove(from);
}
});
// It's important to do this as last action. Since it changes the
// behavior of the SDM in some ways
sdm.addEntityCapabilitiesChangedListener(new EntityCapabilitiesChangedListener() {
@Override
public void onEntityCapabilitiesChanged(DiscoverInfo synthesizedDiscoveryInfo) {
if (!entityCapsEnabled()) {
return;
}
updateLocalEntityCaps(synthesizedDiscoveryInfo);
}
});
}
public static synchronized EntityCapsManager getInstanceFor(XMPPConnection connection) {
if (SUPPORTED_HASHES.size() <= 0)
throw new IllegalStateException("No supported hashes for EntityCapsManager");
EntityCapsManager entityCapsManager = instances.get(connection);
if (entityCapsManager == null) {
entityCapsManager = new EntityCapsManager(connection);
}
return entityCapsManager;
}
public synchronized void enableEntityCaps() {
connection().addPresenceInterceptor(this::addCapsExtension, p -> {
return PresenceTypeFilter.AVAILABLE.accept(p);
});
// Add Entity Capabilities (XEP-0115) feature node.
sdm.addFeature(NAMESPACE);
entityCapsEnabled = true;
}
public synchronized void disableEntityCaps() {
entityCapsEnabled = false;
sdm.removeFeature(NAMESPACE);
connection().removePresenceInterceptor(this::addCapsExtension);
}
public boolean entityCapsEnabled() {
return entityCapsEnabled;
}
/**
* Remove a record telling what entity caps node a user has.
*
* @param user TODO javadoc me please
* the user (Full JID)
*/
public static void removeUserCapsNode(Jid user) {
// While JID_TO_NODEVER_CHACHE has the generic types <Jid, NodeVerHash>, it is ok to call remove with String
// arguments, since the same Jid and String representations would be equal and have the same hash code.
JID_TO_NODEVER_CACHE.remove(user);
}
/**
* Get our own caps version or {@code null} if none is yet set. The version depends on the enabled features.
* A caps version looks like '66/0NaeaBKkwk85efJTGmU47vXI='
*
* @return our own caps version or {@code null}.
*/
public CapsVersionAndHash getCapsVersionAndHash() {
return currentCapsVersion;
}
/**
* Returns the local entity's NodeVer (e.g.
* "http://www.igniterealtime.org/projects/smack/#66/0NaeaBKkwk85efJTGmU47vXI=
* )
*
* @return the local NodeVer
*/
public String getLocalNodeVer() {
CapsVersionAndHash capsVersionAndHash = getCapsVersionAndHash();
if (capsVersionAndHash == null) {
return null;
}
return entityNode + '#' + capsVersionAndHash.version;
}
/**
* Returns true if Entity Caps are supported by a given JID.
*
* @param jid TODO javadoc me please
* @return true if the entity supports Entity Capabilities.
* @throws XMPPErrorException if there was an XMPP error returned.
* @throws NoResponseException if there was no response from the remote entity.
* @throws NotConnectedException if the XMPP connection is not connected.
* @throws InterruptedException if the calling thread was interrupted.
*/
public boolean areEntityCapsSupported(Jid jid) throws NoResponseException, XMPPErrorException, NotConnectedException, InterruptedException {
return sdm.supportsFeature(jid, NAMESPACE);
}
/**
* Returns true if Entity Caps are supported by the local service/server.
*
* @return true if the user's server supports Entity Capabilities.
* @throws XMPPErrorException if there was an XMPP error returned.
* @throws NoResponseException if there was no response from the remote entity.
* @throws NotConnectedException if the XMPP connection is not connected.
* @throws InterruptedException if the calling thread was interrupted.
*/
public boolean areEntityCapsSupportedByServer() throws NoResponseException, XMPPErrorException, NotConnectedException, InterruptedException {
return areEntityCapsSupported(connection().getXMPPServiceDomain());
}
/**
* Updates the local user Entity Caps information with the data provided
*
* If we are connected and there was already a presence send, another
* presence is send to inform others about your new Entity Caps node string.
*
*/
private void updateLocalEntityCaps(DiscoverInfo synthesizedDiscoveryInfo) {
XMPPConnection connection = connection();
DiscoverInfoBuilder discoverInfoBuilder = synthesizedDiscoveryInfo.asBuilder("synthesized-disco-info-result");
// getLocalNodeVer() will return a result only after currentCapsVersion is set. Therefore
// set it first and then call getLocalNodeVer()
currentCapsVersion = generateVerificationString(discoverInfoBuilder);
final String localNodeVer = getLocalNodeVer();
discoverInfoBuilder.setNode(localNodeVer);
final DiscoverInfo discoverInfo = discoverInfoBuilder.build();
addDiscoverInfoByNode(localNodeVer, discoverInfo);
if (lastLocalCapsVersions.size() > 10) {
CapsVersionAndHash oldCapsVersion = lastLocalCapsVersions.poll();
sdm.removeNodeInformationProvider(entityNode + '#' + oldCapsVersion.version);
}
lastLocalCapsVersions.add(currentCapsVersion);
if (connection != null)
JID_TO_NODEVER_CACHE.put(connection.getUser(), new NodeVerHash(entityNode, currentCapsVersion));
final List<Identity> identities = new LinkedList<>(ServiceDiscoveryManager.getInstanceFor(connection).getIdentities());
sdm.setNodeInformationProvider(localNodeVer, new AbstractNodeInformationProvider() {
List<String> features = sdm.getFeatures();
List<DataForm> packetExtensions = sdm.getExtendedInfo();
@Override
public List<String> getNodeFeatures() {
return features;
}
@Override
public List<Identity> getNodeIdentities() {
return identities;
}
@Override
public List<DataForm> getNodePacketExtensions() {
return packetExtensions;
}
});
}
/**
* Verify DiscoverInfo and Caps Node as defined in XEP-0115 5.4 Processing
* Method.
*
* @see <a href="http://xmpp.org/extensions/xep-0115.html#ver-proc">XEP-0115
* 5.4 Processing Method</a>
*
* @param ver TODO javadoc me please
* @param hash TODO javadoc me please
* @param info TODO javadoc me please
* @return true if it's valid and should be cache, false if not
*/
public static boolean verifyDiscoverInfoVersion(String ver, String hash, DiscoverInfo info) {
// step 3.3 check for duplicate identities
if (info.containsDuplicateIdentities())
return false;
// step 3.4 check for duplicate features
if (info.containsDuplicateFeatures())
return false;
// step 3.5 check for well-formed packet extensions
if (!verifyPacketExtensions(info))
return false;
String calculatedVer = generateVerificationString(info, hash).version;
if (!ver.equals(calculatedVer))
return false;
return true;
}
/**
* Verify that the given discovery info is not ill-formed.
*
* @param info the discovery info to verify.
* @return true if the stanza extensions is not ill-formed
*/
private static boolean verifyPacketExtensions(DiscoverInfo info) {
Set<String> foundFormTypes = new HashSet<>();
List<DataForm> dataForms = info.getExtensions(DataForm.class);
for (DataForm dataForm : dataForms) {
FormField formFieldTypeField = dataForm.getHiddenFormTypeField();
if (formFieldTypeField == null) {
continue;
}
String type = formFieldTypeField.getFirstValue();
boolean noDuplicate = foundFormTypes.add(type);
if (!noDuplicate) {
// Ill-formed extension: duplicate forms (by form field type string).
return false;
}
}
return true;
}
static CapsVersionAndHash generateVerificationString(DiscoverInfoView discoverInfo) {
return generateVerificationString(discoverInfo, null);
}
/**
* Generates a XEP-115 Verification String
*
* @see <a href="http://xmpp.org/extensions/xep-0115.html#ver">XEP-115
* Verification String</a>
*
* @param discoverInfo TODO javadoc me please
* @param hash TODO javadoc me please
* the used hash function, if null, default hash will be used
* @return The generated verification String or null if the hash is not
* supported
*/
static CapsVersionAndHash generateVerificationString(DiscoverInfoView discoverInfo, String hash) {
if (hash == null) {
hash = DEFAULT_HASH;
}
// SUPPORTED_HASHES uses the format of MessageDigest, which is uppercase, e.g. "SHA-1" instead of "sha-1"
MessageDigest md = SUPPORTED_HASHES.get(hash.toUpperCase(Locale.US));
if (md == null)
return null;
// Then transform the hash to lowercase, as this value will be put on the wire within the caps element's hash
// attribute. I'm not sure if the standard is case insensitive here, but let's assume that even it is, there could
// be "broken" implementation in the wild, so we *always* transform to lowercase.
hash = hash.toLowerCase(Locale.US);
// 1. Initialize an empty string S ('sb' in this method).
StringBuilder sb = new StringBuilder(); // Use StringBuilder as we don't
// need thread-safe StringBuffer
// 2. Sort the service discovery identities by category and then by
// type and then by xml:lang
// (if it exists), formatted as CATEGORY '/' [TYPE] '/' [LANG] '/'
// [NAME]. Note that each slash is included even if the LANG or
// NAME is not included (in accordance with XEP-0030, the category and
// type MUST be included.
SortedSet<DiscoverInfo.Identity> sortedIdentities = new TreeSet<>();
sortedIdentities.addAll(discoverInfo.getIdentities());
// 3. For each identity, append the 'category/type/lang/name' to S,
// followed by the '<' character.
for (DiscoverInfo.Identity identity : sortedIdentities) {
sb.append(identity.getCategory());
sb.append('/');
sb.append(identity.getType());
sb.append('/');
sb.append(identity.getLanguage() == null ? "" : identity.getLanguage());
sb.append('/');
sb.append(identity.getName() == null ? "" : identity.getName());
sb.append('<');
}
// 4. Sort the supported service discovery features.
SortedSet<String> features = new TreeSet<>();
for (Feature f : discoverInfo.getFeatures())
features.add(f.getVar());
// 5. For each feature, append the feature to S, followed by the '<'
// character
for (String f : features) {
sb.append(f);
sb.append('<');
}
List<DataForm> extendedInfos = discoverInfo.getExtensions(DataForm.class);
for (DataForm extendedInfo : extendedInfos) {
if (!extendedInfo.hasHiddenFormTypeField()) {
// Only use the data form for calculation is it has a hidden FORM_TYPE field.
// See XEP-0115 5.4 step 3.f
continue;
}
// 6. If the service discovery information response includes
// XEP-0128 data forms, sort the forms by the FORM_TYPE (i.e.,
// by the XML character data of the <value/> element).
SortedSet<FormField> fs = new TreeSet<>(new Comparator<FormField>() {
@Override
public int compare(FormField f1, FormField f2) {
return f1.getFieldName().compareTo(f2.getFieldName());
}
});
for (FormField f : extendedInfo.getFields()) {
if (!f.getFieldName().equals("FORM_TYPE")) {
fs.add(f);
}
}
// Add FORM_TYPE values
formFieldValuesToCaps(Collections.singletonList(extendedInfo.getFormType()), sb);
// 7. 3. For each field other than FORM_TYPE:
// 1. Append the value of the "var" attribute, followed by the
// '<' character.
// 2. Sort values by the XML character data of the <value/>
// element.
// 3. For each <value/> element, append the XML character data,
// followed by the '<' character.
for (FormField f : fs) {
sb.append(f.getFieldName());
sb.append('<');
formFieldValuesToCaps(f.getRawValueCharSequences(), sb);
}
}
// 8. Ensure that S is encoded according to the UTF-8 encoding (RFC
// 3269).
// 9. Compute the verification string by hashing S using the algorithm
// specified in the 'hash' attribute (e.g., SHA-1 as defined in RFC
// 3174).
// The hashed data MUST be generated with binary output and
// encoded using Base64 as specified in Section 4 of RFC 4648
// (note: the Base64 output MUST NOT include whitespace and MUST set
// padding bits to zero).
byte[] bytes = sb.toString().getBytes(StandardCharsets.UTF_8);
byte[] digest;
synchronized (md) {
digest = md.digest(bytes);
}
String version = Base64.encodeToString(digest);
return new CapsVersionAndHash(version, hash);
}
private static void formFieldValuesToCaps(List<? extends CharSequence> i, StringBuilder sb) {
SortedSet<CharSequence> fvs = new TreeSet<>();
fvs.addAll(i);
for (CharSequence fv : fvs) {
sb.append(fv);
sb.append('<');
}
}
public static class NodeVerHash {
private String node;
private String hash;
private String ver;
private String nodeVer;
NodeVerHash(String node, CapsVersionAndHash capsVersionAndHash) {
this(node, capsVersionAndHash.version, capsVersionAndHash.hash);
}
NodeVerHash(String node, String ver, String hash) {
this.node = node;
this.ver = ver;
this.hash = hash;
nodeVer = node + "#" + ver;
}
public String getNodeVer() {
return nodeVer;
}
public String getNode() {
return node;
}
public String getHash() {
return hash;
}
public String getVer() {
return ver;
}
}
}