TriggerConstantContract

Invoke the readonly function (modified by the view or pure modifier) of a contract for contract data query; or Invoke the non-readonly function of a contract for predicting whether the transaction can be successfully executed and estimating the energy consumption; or estimate the energy consumption of contract deployment.

This method will use 30 Compute Units.

---

Note:

• TriggerConstantContract operation will not generate an on-chain transaction, nor will it change the status of the current node.

• For estimating energy

  • To estimate the energy consumption of contract deployment just by passing the bytecode of contract through the data field

  • To estimate energy consumption of Contract Calls by calling non-read-only methods of contracts

• When using triggerconstantcontract to estimate energy consumption, the energy_used field in the returned value is the energy consumption. Therefore, the fee_limit of the transaction can be set to energy_used x energy unit price.

• Parameter encoding and decoding example: Parameter and return value encoding and decoding

Parameters

• owner_address - String - Owner address that triggers the contract. If visible=true, use base58check format, otherwise use hex format. For constant call you can use the all-zero address.

• contract_address - String - Smart contract address. If visible=true, use base58check format, otherwise use hex format

• function_selector - String - Function call, must not be left blank

• parameter - String - Parameter encoding needs to be in accordance with the ABI rules, the rules are more complicated, users can use the ethers library to encode,For details, please refer to the document-Guide-Smart Contract-Best Practice-Parameter Encoding and Decoding.

• data - String - The data for interacting with smart contracts, including the contract function and parameters. You can choose to use this field, or you can choose to use function_selector and parameter for contract interaction. When both of data and function_selector exist, function_selector is preferred

• call_value - int64 - Amount of TRX transferred to the contract with this transaction, the unit is sun. This field may be used when estimating energy consumption

• call_token_value - int64 - Amount of TRC10 token transferred with this transaction

• token_id - int64 - TRC10 token id

• visible - boolean - Optional. Specifies whether the address is in Base58 format (default: false)

Returns

Field	Type	Description
result	Return	Run result, for detailed parameter definition, refer to EstimateEnergy
energy_used	int64	Estimated energy consumption, including the basic energy consumption and penalty energy consumption
energy_penalty	int64	The penalty energy consumption
constant_result	string[]	Result list
transaction	Transaction	Transaction information, refer to GetTransactionByID

// Result
{
  "result": {
    "result": true
  },
  "energy_used": 541,
  "constant_result": [
    "00000000000000000000000000000000000000000000000000000001a2127a5b"
  ],
  "transaction": {
    "ret": [
      {}
    ],
    "visible": true,
    "txID": "34c6bae6cc31b8e8d1ee72a73a35125e157907bf2a294f4159b0fd087e68a21d",
    "raw_data": {
      "contract": [
        {
          "parameter": {
            "value": {
              "data": "70a08231000000000000000000000000a614f803b6fd780986a42c78ec9c7f77e6ded13c",
              "owner_address": "TZ4UXDV5ZhNW7fb2AMSbgfAEZ7hWsnYS2g",
              "contract_address": "TG3XXyExBkPp9nzdajDZsozEu4BkaSJozs"
            },
            "type_url": "type.googleapis.com/protocol.TriggerSmartContract"
          },
          "type": "TriggerSmartContract"
        }
      ],
      "ref_block_bytes": "538e",
      "ref_block_hash": "9351f61b61513758",
      "expiration": 1757411406000,
      "timestamp": 1757411347066
    },
    "raw_data_hex": "0a02538e22089351f61b6151375840b0e187ef92335a8e01081f1289010a31747970652e676f6f676c65617069732e636f6d2f70726f746f636f6c2e54726967676572536d617274436f6e747261637412540a1541fd49eda0f23ff7ec1d03b52c3a45991c24cd440e12154142a1e39aefa49290f2b3f9ed688d7cecf86cd6e0222470a08231000000000000000000000000a614f803b6fd780986a42c78ec9c7f77e6ded13c70fa9484ef9233"
  }
}

mainnet

curl https://mainnet.tron.validationcloud.io/v1/<YOUR_API_KEY_HERE>/wallet/triggerconstantcontract \
    -X POST \
    -H "Content-Type: application/json" \
    -d '
{
  "owner_address": "TZ4UXDV5ZhNW7fb2AMSbgfAEZ7hWsnYS2g",
  "contract_address": "TG3XXyExBkPp9nzdajDZsozEu4BkaSJozs",
  "function_selector": "balanceOf(address)",
  "parameter": "000000000000000000000000a614f803b6fd780986a42c78ec9c7f77e6ded13c",
  "visible": true
}
'