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Get topic info
Topic info returns 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.
Ledger ID
The ID of the network the response came from. See HIP-198.
Query Signing Requirements
  • The client operator private key is required to sign the query request
Query Fees
  • Please see the transaction and query fees table for base transaction fee
  • Please use the Hedera fee estimator to estimate your query fee cost
V2
V1
Constructor
Description
new TopicInfoQuery()
Initializes the TopicInfoQuery object
new TopicInfoQuery()
Method
Type
Requirement
setTopicId(<topicId>)
TopicId
Required
<TopicInfo>.adminKey
​Key​
Optional
<TopicInfo>.submitKey
​Key​
Optional
<TopicInfo>.topicId
​TopicId​
Optional
<TopicInfo>.sequenceNumber
long
Optional
<TopicInfo>.runningHash
ByteString
Optional
<TopicInfo>.memo
String
Optional
<TopicInfo>.ledgerId
LedgerId
Optional
<TopicInfo>.expirationTime
Instant
Optional
<TopicInfo>.autoRenewAccount
​AccountId​
Optional
<TopicInfo>.autoRenewPeriod
Instant
Optional
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
}
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
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