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QBFT methods

The QBFT API methods provide access to the QBFT consensus engine.

note

The QBFT API is not enabled by default for JSON-RPC. Enable it using the --rpc-http-api or --rpc-ws-api option.

qbft_discardValidatorVote​

Discards a proposal to add or remove a validator with the specified address.

Parameters​

  • address: string - 20-byte address of the proposed validator.

Returns​

  • Indicates if the proposal is discarded.

Example​

curl -X POST http://127.0.0.1:8545/ \
  -H "Content-Type: application/json" \
  --data '{
    "jsonrpc": "2.0",
    "method": "qbft_discardValidatorVote",
    "params": [
      "0xef1bfb6a12794615c9b0b5a21e6741f01e570185"
    ],
    "id": 1
  }'

qbft_getPendingVotes​

Returns votes cast in the current epoch.

Parameters​

  • None

Returns​

  • Account addresses mapped to boolean values indicating the vote for each account. true is a vote to add a validator; false is a vote to remove a validator.

Example​

curl -X POST http://127.0.0.1:8545/ \
  -H "Content-Type: application/json" \
  --data '{
    "jsonrpc": "2.0",
    "method": "qbft_getPendingVotes",
    "params": [],
    "id": 1
  }'

qbft_getSignerMetrics​

Provides the following validator metrics for the specified range:

  • Number of blocks from each validator.
  • Block number of the last block proposed by each validator (if any proposed in the specified range).
  • All validators present in the last block of the range.

Parameters​

  • fromBlockNumber: string - (Optional) Hexadecimal integer representing a block number, or one of the string tags latest, earliest, pending, finalized, or safe, as described in block parameter.

  • toBlockNumber: string - (Optional) Hexadecimal integer representing a block number, or one of the string tags latest, earliest, pending, finalized, or safe, as described in block parameter.

note

pending returns the same value as latest.

If you specify:

  • No parameters, the call provides metrics for the last 100 blocks, or all blocks if there are fewer than 100 blocks.
  • Only the first parameter, the call provides metrics for all blocks from the specified block to the latest block.

Returns​

  • List of validator objects.

    • address: string - Address of the validator.

      note

      The proposer of the genesis block has address 0x0000000000000000000000000000000000000000.

    • proposedBlockCount: string - Hexadecimal integer representing the number of blocks proposed by the validator in the specified range.

    • lastProposedBlockNumber: string - Hexadecimal integer representing the block number of the last block proposed by the validator in the specified range.

Example​

curl -X POST http://127.0.0.1:8545/ \
  -H "Content-Type: application/json" \
  --data '{
    "jsonrpc": "2.0",
    "method": "qbft_getSignerMetrics",
    "params": [
      "0x1",
      "0x64"
    ],
    "id": 1
  }'

qbft_getValidatorsByBlockHash​

Lists the validators defined in the specified block.

Parameters​

  • block: string - 32-byte block hash.

Returns​

  • List of validator addresses.

Example​

curl -X POST http://127.0.0.1:8545/ \
  -H "Content-Type: application/json" \
  --data '{
    "jsonrpc": "2.0",
    "method": "qbft_getValidatorsByBlockHash",
    "params": [
      "0xbae7d3feafd743343b9a4c578cab5e5d65eb735f6855fb845c00cab356331256"
    ],
    "id": 1
  }'

qbft_getValidatorsByBlockNumber​

Lists the validators for the specified block.

For all blocks up to the chain head block, this method returns the validators that were used at the time the block was produced. Use blockNumber to get the list of validators for that block.

For the chain head block, there are two validator lists associated with it:

  1. The validators that were used at the time the block was produced. Passing latest as the input parameter returns this list.
  2. The validators that will be used to produce the next block. Passing pending as the input parameter returns this list.

In most instances, the two lists for the chain head block are the same. However, when voting has completed to add or remove a validator, the validators that will be used to produce the next block are different. Comparing the two lists can help when diagnosing a stalled chain.

note

When the validator list changes, an INFO log message displays, showing the previous list of validators and the new list of validators.

Parameters​

  • blockNumber: string - Hexadecimal integer representing a block number, or one of the string tags latest, earliest, pending, finalized, or safe, as described in block parameter.

Returns​

  • List of validator addresses.

Example​

curl -X POST http://127.0.0.1:8545/ \
  -H "Content-Type: application/json" \
  --data '{
    "jsonrpc": "2.0",
    "method": "qbft_getValidatorsByBlockNumber",
    "params": [
      "latest"
    ],
    "id": 1
  }'

qbft_proposeValidatorVote​

Proposes to add or remove a validator with the specified address.

Parameters​

  • address: string - Account address.

  • proposal: boolean - true to propose adding a validator, or false to propose removing a validator.

Returns​

  • true

Example​

curl -X POST http://127.0.0.1:8545/ \
  -H "Content-Type: application/json" \
  --data '{
    "jsonrpc": "2.0",
    "method": "qbft_proposeValidatorVote",
    "params": [
      "0x42d4287eac8078828cf5f3486cfe601a275a49a5",
      true
    ],
    "id": 1
  }'