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Smart contract methods#

Node RPC call example:

curl -X POST --data '{
"jsonrpc":"2.0",
"key":"myAPIkey",
"id":1,
"method":"contract_call",
"params": [
{
"from": "0x...",
"contract": "0x...",
"method": "transfer",
"args": [
{
"index": 0,
"format": "hex",
"value": "0xcbb98....91"
},
{
"index": 1,
"format": "dna",
"value": "1000"
}
]
}
]
}'

Args#

Smart contract methods may have a dynamic list of parameters args that is specific to each smart contract:

[
{
"index": 0,
"format": "hex",
"value": "0x11"
},
{
"index": 1,
"format": "uint64",
"value": "11"
}
]
  • Index: index of parameter
  • Format: format of parameter byte, uint64, string, bigint, hex (default), dna (float representation).
  • Value: parameter value interpreted according to the specified format

contract_deploy and contract_estimateDeploy methods#

Method contract_deploy creates DeployContractTx transaction to deploy a custom contract specified by code and nonce or a predefined contract specified by codeHash. Use contract_estimateDeploy method to estimate gas consumption of the future DeployContractTx transaction and address of the future contract.

Parameters for custom contract:

  • from: sender address
  • code: compiled WebAssembly code of a custom contract
  • args: dynamic list of parameters of constructor which is specific to a particular contract
  • nonce: unique nonce for the custom contract (allows you to generate unique addresses for contracts with the same code and args)
  • maxFee: must cover a sum of txFee+gasCost (see more about maxFee)

Example:

{
"method": "contract_estimateDeploy",
"params": [
{
"from": "<address>",
"code": "0x0061736d01000000013...",
"nonce": "0x01",
"maxFee": 1,
"args": [
{
"index": 0,
"format": "uint64",
"value": "0"
}
]
}
],
"id": 1,
"key": "<key>"
}

Parameters for predefined contract:

  • from: sender address
  • codeHash: predefined smart contract code
  • amount: amount of coins that will be blocked at the smart contract stake
  • args: dynamic list of parameters relevant to the specified smart contract
  • maxFee: must cover a sum of txFee+gasCost (see more about maxFee)

Example:

{
"method": "contract_estimateDeploy",
"params": [
{
"from": "<address>",
"codeHash": "0x01",
"amount": 1100,
"maxFee": 1,
"args": [
{
"index": 0,
"format": "uint64",
"value": "0"
}
]
}
],
"id": 1,
"key": "<key>"
}

contract_call and contract_estimateCall methods#

Method contract_call creates CallContractTx transaction to call specified contract's method. Use contract_estimateCall method to estimate gas consumption of the future CallContractTx transaction.

Parameters:

  • from: sender address
  • contract: contract address
  • method: name of the called contract's method
  • amount: amount of coins transferred to the contract address
  • args: dynamic list of parameters relevant to specified contract's method
  • broadcastBlock: block number when a postponed transaction should be published by the node

Example:

{
{
"method": "contract_estimateCall",
"params": [
{
"from": "<sender address>",
"contract": "<smart contract address>",
"method": "transfer",
"amount": 123,
"maxFee": 1,
"args": [
{
"index": 0,
"format": "hex",
"value": "<address>"
},
{
"index": 1,
"format": "dna",
"value": "123"
}
]
}
],
"id": 1,
"key": "<key>"
}

contract_terminate and contract_estimateTerminate methods#

Method contract_terminate creates TerminateContractTx transaction to terminate the contract. Use contract_estimateTerminate method to estimates gas consumption of the future TerminateContractTx transaction.

Parameters:

  • from: sender address
  • contract: contract address
  • args: dynamic list of parameters relevant to specified contract's method

Example:

{
"method": "contract_estimateTerminate",
"params": [
{
"from": "<sender address>",
"contract": "<smart contract address>",
"maxFee": 1,
"args": [
{
"index": 0,
"format": "hex",
"value": "<Destination address>"
}
]
}
]
}

contract_readData method#

Returns requested data of the smart contract's state.

Parameters:

  • contract: smart contract address
  • key: key of the requested data
  • format: data format

Example:

{
"method": "contract_readData",
"params": ["<smart contract address>", "key", "hex"]
}

contract_iterateMap method#

Returns requested array data (map) of the smart contract's state and continuation token to iterate the data.

Parameters:

  • contract: smart contract address
  • map: the name of the requested array data (see maps available for the specific smart contract)
  • continuationToken: iteration token should be null for the first call
  • keyFormat: key format of the requested array data
  • valueFormat: data format of the requested array data

Example:

{
"method": "contract_iterateMap",
"params": [
"<smart contract address>",
"addr", //map name
null, //continuationToken
"hex", //keyFormat
"hex", //valueFormat
10
]
}

contract_readMap method#

Returns requested value for the given key from the array data (map) of the smart contract's state.

Parameters:

  • contract: smart contract address
  • map: the name of the requested array data (see maps available for the specific smart contract)
  • key: key of the requested array data
  • valueFormat: data format of the requested array data

Example:

{
"method": "contract_readMap",
"params": [
"<smart contract address>",
"addr",
"0x725....70", //key in the array data
"hex"
]
}

contract_readonlyCall method#

Calls specified smart contract's method without changing the state.

Parameters:

  • contract: smart contract address
  • method: key of the requested data
  • format: data format
  • args: dynamic list of parameters

Example:

{
"method": "contract_readonlyCall",
"params": [
{
"contract": "<smart contract address>",
"method": "getHash",
"format": "hex",
"args": [
{
"index": 0,
"format": "hex",
"value": "123"
}
]
}
]
}

contract_getStake method#

Returns amount of coins blocked at the stake of the smart contract

Parameters:

  • Contract: smart contract address

Example:

{
"method": "contract_getStake",
"params": ["<smart contract address>"]
}

bcn_txReceipt method#

Returns receipt of the specified transaction

Parameters:

  • hash: hash of mined transaction

Example:

{
"method": "bcn_txReceipt",
"params": ["<transaction hash>"]
}

Response example:

{
"jsonrpc": "2.0",
"id": 1,
"result": {
"contract": "...",
"method": "...",
"success": false,
"gasUsed": 200,
"txHash": "0x217...",
"error": "index out of range",
"gasCost": "0.00032916392364",
"txFee": "0.002320605661662"
}
}
  • contract: address of the called contract
  • method: called method of the smart contract
  • success: whether transaction changed the state or not
  • gasUsed: amount of gas used
  • txHash: contract transaction hash
  • error: error text
  • gasCost: gas cost, iDNA
  • txFee: transaction cost, iDNA

Errors:

  • index out of range: args array has a missing element with required index.

contract_events method#

Returns the list of events of the specified smart contract

Parameters:

  • contract: smart contract address

Example:

{
"method": "contract_events",
"params": [
{
"contract": "<smart contract address>"
}
]
}

contract_subscribeToEvent and contract_unsubscribeFromEvent methods#

Subscribes/unsubscribes from the specified event of the smart contract

Parameters:

  • contract: smart contract address
  • event: event name

Example:

{
"method": "contract_subscribeToEvent",
"params": ["<smart contract address>", "<event name>"]
}

bcn_feePerGas method#

The method returns the current gasPrice.

Example:

{
"method": "bcn_feePerGas",
"params": [],
"id": 1,
"key": "<API key>"
}

Example:

{
"result": 1651527663100 //0.0000016515276631 iDNA
}

The minimum gasPrice is 0.01/NetworkSize.

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