Get topic info

Topic info returns the the following values for a topic. Queries do not change the state of the topic or require network consensus. The information is returned from a single node processing the query.

Topic Info Response:

Field

Description

Topic ID

The ID of the topic

Admin Key

Access control for update/delete of the topic. Null if there is no key.

Submit Key

Access control for ConsensusService.submitMessage. Null if there is no key.

Sequence Number

Current sequence number (starting at 1 for the first submitMessage) of messages on the topic.

Running Hash

SHA-384 running hash

Expiration Time

Effective consensus timestamp at (and after) which submitMessage calls will no longer succeed on the topic and the topic will expire and be marked as deleted.

Topic Memo

Short publicly visible memo about the topic. No guarantee of uniqueness.

Auto Renew Period

The lifetime of the topic and the amount of time to extend the topic's lifetime by

Auto Renew Account

Null if there is no autoRenewAccount.

Query Signing Requirements

  • The client operator private key is required to sign the query request

V2
V1
V2

Constructor

Description

new TopicInfoQuery()

Initializes the TopicInfoQuery object

new TopicInfoQuery()

Method

Type

Description

Requirement

setTopicId(<topicId>)

TopicId

The ID of the topic to get information for

Required

Java
//Create the account info query
TopicInfoQuery query = new TopicInfoQuery()
.setTopicId(newTopicId);
//Submit the query to a Hedera network
TopicInfo info = query.execute(client);
//Print the account key to the console
System.out.println(info);
//v2.0.0
JavaScript
//Create the account info query
const query = new TopicInfoQuery()
.setTopicId(newTopicId);
//Submit the query to a Hedera network
const info = await query.execute(client);
//Print the account key to the console
console.log(info);
//v2.0.0
Go
//Create the account info query
query, err := hedera.NewTopicInfoQuery().
SetTopicID(topicID)
//Submit the query to a Hedera network
info, err := query.Execute(client)
if err != nil {
panic(err)
}
//Print the account key to the console
println(info)
//v2.0.0

Sample Output:

TopicInfo{ topicId=0.0.102736, topicMemo=, runningHash=[ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0. 0, 0,0,0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,0, 0, 0, 0, 0, 0, 0 ], sequenceNumber=0, expirationTime=2021-02-09T03:17:07.258292001Z, adminKey=null, submitKey=null, autoRenewPeriod=PT2160H, autoRenewAccountId=null }

V1

Constructor

Description

new ConsensusTopicInfoQuery()

Initializes the ConsensusTopicInfoQuery object

new ConsensusTopicInfoQuery()

Method

Type

Description

Requirement

setTopicId(<topicId>)

TopicId

The ID of the topic to get information for

Required

Java
//Create the account info query
TopicInfoQuery query = new ConsensusTopicInfoQuery()
.setTopicId(newTopicId);
//Submit the query to a Hedera network
TopicInfo info = query.execute(client);
//Print the account key to the console
System.out.println(info);
//v1.3.2
JavaScript
//Create the account info query
const query = new ConsensusTopicInfoQuery()
.setTopicId(newTopicId);
//Submit the query to a Hedera network
const info = await query.execute(client);
//Print the account key to the console
console.log(info);
//v1.4.4