聊聊claudb的pubsub command
时间:2022-07-24
本文章向大家介绍聊聊claudb的pubsub command,主要内容包括其使用实例、应用技巧、基本知识点总结和需要注意事项,具有一定的参考价值,需要的朋友可以参考一下。
序
本文主要研究一下claudb的pubsub command
PublishCommand
claudb-1.7.1/src/main/java/com/github/tonivade/claudb/command/pubsub/PublishCommand.java
@Command("publish")
@ParamLength(2)
public class PublishCommand implements DBCommand, SubscriptionSupport, PatternSubscriptionSupport {
@Override
public RedisToken execute(Database db, Request request) {
String channel = request.getParam(0).toString();
SafeString message = request.getParam(1);
return integer(publishAll(getClauDB(request.getServerContext()), channel, message));
}
private int publishAll(DBServerContext server, String channel, SafeString message) {
int count = publish(server, channel, message);
int pcount = patternPublish(server, channel, message);
return count + pcount;
}
}
- PublishCommand实现了DBCommand, SubscriptionSupport, PatternSubscriptionSupport接口,其execute方法执行publishAll(getClauDB(request.getServerContext()), channel, message)
SubscribeCommand
claudb-1.7.1/src/main/java/com/github/tonivade/claudb/command/pubsub/SubscribeCommand.java
@ReadOnly
@Command("subscribe")
@ParamLength(1)
@PubSubAllowed
public class SubscribeCommand implements DBCommand, SubscriptionSupport {
private static final String SUBSCRIBE = "subscribe";
@Override
public RedisToken execute(Database db, Request request) {
Database admin = getAdminDatabase(request.getServerContext());
String sessionId = getSessionId(request);
Sequence<SafeString> channels = getChannels(request);
int i = channels.size();
List<Object> result = new LinkedList<>();
for (SafeString channel : request.getParams()) {
addSubscription(admin, sessionId, channel);
getSessionState(request.getSession()).addSubscription(channel);
result.addAll(asList(SUBSCRIBE, channel, ++i));
}
return convert(result);
}
private String getSessionId(Request request) {
return request.getSession().getId();
}
private Sequence<SafeString> getChannels(Request request) {
return getSessionState(request.getSession()).getSubscriptions();
}
}
- SubscribeCommand实现了DBCommand, SubscriptionSupport接口,其execute方法遍历channel挨个执行addSubscription及getSessionState(request.getSession()).addSubscription(channel)
UnsubscribeCommand
claudb-1.7.1/src/main/java/com/github/tonivade/claudb/command/pubsub/UnsubscribeCommand.java
@ReadOnly
@Command("unsubscribe")
@ParamLength(1)
@PubSubAllowed
public class UnsubscribeCommand implements DBCommand, SubscriptionSupport {
private static final String UNSUBSCRIBE = "unsubscribe";
@Override
public RedisToken execute(Database db, Request request) {
Database admin = getAdminDatabase(request.getServerContext());
String sessionId = getSessionId(request);
Sequence<SafeString> channels = getChannels(request);
int i = channels.size();
List<Object> result = new LinkedList<>();
for (SafeString channel : request.getParams()) {
removeSubscription(admin, sessionId, channel);
getSessionState(request.getSession()).removeSubscription(channel);
result.addAll(asList(UNSUBSCRIBE, channel, --i));
}
return convert(result);
}
private String getSessionId(Request request) {
return request.getSession().getId();
}
private Sequence<SafeString> getChannels(Request request) {
return getSessionState(request.getSession()).getSubscriptions();
}
}
- UnsubscribeCommand实现了DBCommand, SubscriptionSupport接口,其execute方法遍历channel挨个执行removeSubscription(admin, sessionId, channel)及getSessionState(request.getSession()).removeSubscription(channel)
PatternSubscribeCommand
claudb-1.7.1/src/main/java/com/github/tonivade/claudb/command/pubsub/PatternSubscribeCommand.java
@ReadOnly
@Command("psubscribe")
@ParamLength(1)
@PubSubAllowed
public class PatternSubscribeCommand implements DBCommand, PatternSubscriptionSupport {
private static final String PSUBSCRIBE = "psubscribe";
@Override
public RedisToken execute(Database db, Request request) {
Database admin = getAdminDatabase(request.getServerContext());
String sessionId = getSessionId(request);
Sequence<SafeString> channels = getChannels(request);
int i = channels.size();
List<Object> result = new LinkedList<>();
for (SafeString pattern : request.getParams()) {
addPatternSubscription(admin, sessionId, pattern);
getSessionState(request.getSession()).addSubscription(pattern);
result.addAll(asList(PSUBSCRIBE, pattern, ++i));
}
return convert(result);
}
private String getSessionId(Request request) {
return request.getSession().getId();
}
private Sequence<SafeString> getChannels(Request request) {
return getSessionState(request.getSession()).getSubscriptions();
}
}
- PatternSubscribeCommand实现了DBCommand, PatternSubscriptionSupport接口,其execute方法遍历pattern挨个执行addPatternSubscription(admin, sessionId, pattern)及getSessionState(request.getSession()).addSubscription(pattern)
PatternUnsubscribeCommand
claudb-1.7.1/src/main/java/com/github/tonivade/claudb/command/pubsub/PatternUnsubscribeCommand.java
@ReadOnly
@Command("punsubscribe")
@ParamLength(1)
@PubSubAllowed
public class PatternUnsubscribeCommand implements DBCommand, PatternSubscriptionSupport {
private static final String PUNSUBSCRIBE = "punsubscribe";
@Override
public RedisToken execute(Database db, Request request) {
Database admin = getAdminDatabase(request.getServerContext());
String sessionId = getSessionId(request);
Sequence<SafeString> channels = getChannels(request);
int i = channels.size();
List<Object> result = new LinkedList<>();
for (SafeString channel : request.getParams()) {
removePatternSubscription(admin, sessionId, channel);
getSessionState(request.getSession()).removeSubscription(channel);
result.addAll(asList(PUNSUBSCRIBE, channel, --i));
}
return convert(result);
}
private String getSessionId(Request request) {
return request.getSession().getId();
}
private Sequence<SafeString> getChannels(Request request) {
return getSessionState(request.getSession()).getSubscriptions();
}
}
- PatternUnsubscribeCommand实现了DBCommand, PatternSubscriptionSupport接口,其execute遍历channel挨个执行removePatternSubscription(admin, sessionId, channel)及getSessionState(request.getSession()).removeSubscription(channel)
小结
claudb pubsub相关的command有PublishCommand、SubscribeCommand、UnsubscribeCommand、PatternSubscribeCommand、PatternUnsubscribeCommand
doc
- command/pubsub
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