IconScoreBase

class IconScoreBase(db: iconservice.database.db.IconScoreDatabase)

A base class of SCOREs. this class provides facilities and environments to SCORE to run.

__init__(self, db: iconservice.database.db.IconScoreDatabase) → None

A python init function. Invoked when the contract is loaded at each node.

on_install(self, **kwargs) → None

Invoked when the contract is deployed for the first time, and will not be called again on contract update or deletion afterward. This is the place where you initialize the state DB.

on_update(self, **kwargs) → None

Invoked when the contract is deployed for update This is the place where you migrate old states.

fallback(self) → None

fallback function can not be decorated with @external. (i.e., fallback function is not allowed to be called by external contract or user.) This fallback function is executed whenever the contract receives plain icx coins without data. If the fallback function is not decorated with @payable, the icx coin transfers to the contract will fail.

call(self, addr_to: iconservice.base.address.Address, func_name: str, kw_dict: dict, amount: int = 0)

Call external function provided by other IconScore with arguments without fallback

Parameters:

• addr_to – Address the address of other IconScore
• func_name – function name provided by other IconScore
• kw_dict – Arguments of the external function
• amount – ICX value to enclose with. in loop.

Returns:

returning value of the external function

create_interface_score(self, addr_to: iconservice.base.address.Address, interface_cls: Callable[[Address, callable], T]) → T

Creates an object, through which you have an access to the designated SCORE’s external functions.

Parameters:

• addr_to – SCORE address
• interface_cls – interface class

Returns:

An instance of given class

now(self) → int

Timestamp of current block in microseconds

Returns:timestamp in microseconds

msg

Holds information of calling the SCORE

• msg.sender : Address of the account who called this function. If other contact called this function, msg.sender points to the caller contract’s address.
• msg.value : Amount of icx that the sender attempts to transfer to the current SCORE.

address

The current SCORE address

Returns:Address current address

tx

Holds information of the transaction

Returns:Transaction transaction

db

An instance used to access state DB

Returns:IconScoreDatabase db

owner

Address of the account who deployed the contract

Returns:Address owner address

icx

An object used to transfer icx coin

• icx.transfer(addr_to(address), amount(integer)) -> bool Transfers designated amount of icx coin to addr_to. If exception occurs during execution, the exception will be escalated. Returns True if coin transfer succeeds.
• icx.send(addr_to(address), amount(integer)) -> bool Sends designated amount of icx coin to addr_to. Basic behavior is same as transfer, the difference is that exception is caught inside the function. Returns True when coin transfer succeeded, False when failed.

Returns:Icx instance of icx

block_height

Current block height

Returns:current block height