contractmanagement

class ContractManagement

Bases: object

A class used to represent the ContractManagement native contract.

Check out Neo’s Documentation to learn more about the ContractManagement class.

hash: UInt160

classmethod get_minimum_deployment_fee() → int

Gets the minimum fee of contract deployment.

>>> ContractManagement.get_minimum_deployment_fee()
1000000000

Returns:: the minimum fee of contract deployment

classmethod get_contract(script_hash: UInt160) → Optional[Contract]

Gets a contract with a given hash. If the script hash is not associated with a smart contract, then it will return None.

>>> ContractManagement.get_contract(UInt160(b'\xcfv\xe2\x8b\xd0\x06,JG\x8e\xe3Ua\x01\x13\x19\xf3\xcf\xa4\xd2'))    # GAS script hash
{
    'id': -6,
    'update_counter': 0,
    'hash': b'\xcfv\xe2\x8b\xd0\x06,JG\x8e\xe3Ua\x01\x13\x19\xf3\xcf\xa4\xd2',
    'nef': b'NEF3neo-core-v3.0\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00#\x10A\x1a\xf7{g@\x10A\x1a\xf7{g@\x10A\x1a\xf7{g@\x10A\x1a\xf7{g@\x10A\x1a\xf7{g@QA\xc7\x9e',
    'manifest': {
        'name': 'GasToken',
        'group': [],
        'supported_standards': ['NEP-17'],
        'abi': [[['balanceOf', [['account', 20]], 17, 0, True], ['decimals', [], 17, 7, True], ['symbol', [], 19, 14, True], ['totalSupply', [], 17, 21, True], ['transfer', [['from', 20], ['to', 20], ['amount', 17], ['data', 0]], 16, 28, False]], [['Transfer', [['from', 20], ['to', 20], ['amount', 17]]]]],
        'permissions': [[None, None]],
        'trusts': [],
        'extras': 'null'
    },
}

>>> ContractManagement.get_contract(UInt160(bytes(20)))    # there is no smart contract associated with this script hash
None

Parameters:: script_hash (UInt160) – a smart contract hash
Returns:: a contract
Return type:: Contract
Raises:: Exception – raised if hash length isn’t 20 bytes.

classmethod has_method(hash: UInt160, method: str, parameter_count: int) → bool

Check if a method exists in a contract.

>>> ContractManagement.has_method(UInt160(b'\xcfv\xe2\x8b\xd0\x06,JG\x8e\xe3Ua\x01\x13\x19\xf3\xcf\xa4\xd2'),
...                               'balanceOf', 1)    # GAS script hash
True

>>> ContractManagement.has_method(UInt160(b'\xcfv\xe2\x8b\xd0\x06,JG\x8e\xe3Ua\x01\x13\x19\xf3\xcf\xa4\xd2'),
...                               'balanceOf', 10)    # GAS script hash
False

>>> ContractManagement.has_method(UInt160(b'\xcfv\xe2\x8b\xd0\x06,JG\x8e\xe3Ua\x01\x13\x19\xf3\xcf\xa4\xd2'),
...                               'invalid', 1)    # GAS script hash
False

Parameters:

hash (UInt160) – The hash of the deployed contract
method (str) – The name of the method
parameter_count (int) – The number of parameters

Returns:

whether the method exists or not

Return type:

bool

Raises:

Exception – raised if hash length isn’t 20 bytes or if the parameter_count is less than 0.

classmethod deploy(nef_file: bytes, manifest: bytes, data: Optional[Any] = None) → Contract

Creates a smart contract given the script and the manifest.

>>> nef_file_ = get_script(); manifest_ = get_manifest()    # get the script and manifest somehow
... ContractManagement.deploy(nef_file_, manifest_, None)             # smart contract will be deployed
{
    'id': 2,
    'update_counter': 0,
    'hash': b'\x92\x8f+1q\x86z_@\x94\xf5pE\xcb\xb8 \x0f\\`Z',
    'nef': b'NEF3neo3-boa by COZ-1.0.0\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x07W\x00\x02xy\x9e@\xf9\7b\xbb\xcc',
    'manifest': {
        'name': 'TestContract',
        'group': [],
        'supported_standards': [],
        'abi': [[['test', [['a', 17], ['b', 17]], 17, 0, False]], []],
        'permissions': [],
        'trusts': [],
        'extras': 'null'
    },
}

Parameters:

nef_file (bytes) – the target smart contract’s compiled nef
manifest (bytes) – the manifest.json that describes how the script should behave
data (Any) – the parameters for the _deploy function

Returns:

the contract that was created

Return type:

Contract

Raises:

Exception – raised if the nef or the manifest are not a valid smart contract.

classmethod update(nef_file: bytes, manifest: bytes, data: Optional[Any] = None)

Updates the executing smart contract given the script and the manifest.

>>> nef_file_ = get_script(); manifest_ = get_manifest()    # get the script and manifest somehow
... ContractManagement.update(nef_file_, manifest_, None)             # smart contract will be updated
None

Parameters:

nef_file (bytes) – the new smart contract’s compiled nef
manifest (bytes) – the new smart contract’s manifest
data (Any) – the parameters for the _deploy function

Raises:

Exception – raised if the nef and the manifest are not a valid smart contract or the new contract is the same as the old one.

classmethod destroy()

Destroy the executing smart contract.

>>> ContractManagement.destroy()
None

class Contract

Bases: object

Represents a contract that can be invoked.

Check out Neo’s Documentation to learn about Smart Contracts.

Variables:

id (int) – the serial number of the contract
update_counter (int) – the number of times the contract was updated
hash (UInt160) – the hash of the contract
nef (bytes) – the serialized Neo Executable Format (NEF) object holding of the smart contract code and compiler information
manifest (ContractManifest) – the manifest of the contract