Types

Data types for SRC20 event watching

Data types for decoded SRC20 events and callbacks.

Overview

The types module provides frozen dataclasses for decoded SRC20 events with decrypted amounts, as well as type aliases for callbacks.

Event Data Types

Type	Description
DecryptedTransferLog	Transfer event with decrypted amount
DecryptedApprovalLog	Approval event with decrypted amount

Quick Reference

DecryptedTransferLog

@dataclass(frozen=True)
class DecryptedTransferLog:
    from_address: ChecksumAddress
    to_address: ChecksumAddress
    encrypt_key_hash: bytes
    encrypted_amount: bytes
    decrypted_amount: int
    transaction_hash: HexBytes
    block_number: int

DecryptedApprovalLog

@dataclass(frozen=True)
class DecryptedApprovalLog:
    owner: ChecksumAddress
    spender: ChecksumAddress
    encrypt_key_hash: bytes
    encrypted_amount: bytes
    decrypted_amount: int
    transaction_hash: HexBytes
    block_number: int

Callback Type Aliases

Sync Callbacks

TransferCallback = Callable[[DecryptedTransferLog], None]
ApprovalCallback = Callable[[DecryptedApprovalLog], None]
ErrorCallback = Callable[[Exception], None]

Async Callbacks

AsyncTransferCallback = Callable[[DecryptedTransferLog], Awaitable[None]]
AsyncApprovalCallback = Callable[[DecryptedApprovalLog], Awaitable[None]]
AsyncErrorCallback = Callable[[Exception], Awaitable[None]]

Example Usage

Transfer Event

from seismic_web3.src20 import watch_src20_events, DecryptedTransferLog

def on_transfer(log: DecryptedTransferLog):
    print(f"Transfer from {log.from_address} to {log.to_address}")
    print(f"Amount: {log.decrypted_amount}")
    print(f"Block: {log.block_number}")

watcher = watch_src20_events(
    w3,
    encryption=w3.seismic.encryption,
    private_key=private_key,
    on_transfer=on_transfer,
)

Approval Event

from seismic_web3.src20 import watch_src20_events, DecryptedApprovalLog

def on_approval(log: DecryptedApprovalLog):
    print(f"Approval from {log.owner} to {log.spender}")
    print(f"Amount: {log.decrypted_amount}")
    print(f"Block: {log.block_number}")

watcher = watch_src20_events(
    w3,
    encryption=w3.seismic.encryption,
    private_key=private_key,
    on_approval=on_approval,
)

Both Events

from seismic_web3.src20 import (
    watch_src20_events,
    DecryptedTransferLog,
    DecryptedApprovalLog,
)

def on_transfer(log: DecryptedTransferLog):
    print(f"Transfer: {log.decrypted_amount}")

def on_approval(log: DecryptedApprovalLog):
    print(f"Approval: {log.decrypted_amount}")

watcher = watch_src20_events(
    w3,
    encryption=w3.seismic.encryption,
    private_key=private_key,
    on_transfer=on_transfer,
    on_approval=on_approval,
)

Common Fields

Both event types share common fields:

Field	Type	Description
encrypt_key_hash	bytes	32-byte hash of viewing key (used for filtering)
encrypted_amount	bytes	Raw AES-GCM ciphertext with auth tag
decrypted_amount	int	Decrypted token amount (raw value)
transaction_hash	HexBytes	Transaction hash containing the event
block_number	int	Block number containing the event

Properties

Immutability

All event types are frozen dataclasses:

log.decrypted_amount = 1000  # Raises AttributeError

Type Safety

All fields use proper types:

• Addresses are checksummed (ChecksumAddress)

• Transaction hashes are HexBytes

• Amounts are Python integers

• Block numbers are integers

Notes

• All event dataclasses are immutable (frozen)

• Addresses are automatically checksummed

• Amounts are raw values (consider token decimals)

• Encrypted amounts include authentication tags

• Created automatically by event watchers

See Also

• Event Watching - Watch and decrypt SRC20 events

• Directory - Manage viewing keys

• SRC20 Overview - Full SRC20 documentation