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Subscribe to a topic ID’s messages from a mirror node. You will receive all messages for the specified topic or within the defined start and end time. Query Fees

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Methods

MethodTypeDescriptionRequirement
setTopicId(<topicId>)TopicIdThe topic ID to subscribe toRequired
setStartTime(<startTime>)InstantThe time to start subscribing to a topic’s messagesOptional
setEndTime(<endTime>)InstantThe time to stop subscribing to a topic’s messagesOptional
setLimit(<limit>)longThe number of messages to returnOptional
subscribe(<client, onNext)SubscriptionHandleClient, Consumer<TopicMessage>Required
//Create the query
new TopicMessageQuery()
    .setTopicId(newTopicId)
    .subscribe(client, topicMessage -> {
        System.out.println("at " + topicMessage.consensusTimestamp + " ( seq = " + topicMessage.sequenceNumber + " ) received topic message of " + topicMessage.contents.length + " bytes");
    });

//v2.0.0

//Create the query
new TopicMessageQuery()
        .setTopicId(topicId)
        .setStartTime(0)
        .subscribe(
            client,
            (message) => console.log(Buffer.from(message.contents, "utf8").toString())
        );
//v2.0.0

//Create the query
_, err = hedera.NewTopicMessageQuery().
    SetTopicID(topicID).
    Subscribe(client, func(message hedera.TopicMessage) {
        if string(message.Contents) == content {
        wait = false
    }
})

if err != nil {
    panic(err)
}

//v2.0.0