ink! exposes a number of handy environment functions. A full overview is found here.
Self::env() to access those,
Some handy functions include:
caller(): Returns the address of the caller of the executed contract.
account_id(): Returns the account ID of the executed contract.
balance(): Returns the balance of the executed contract.
block_number(): Returns the current block number.
random(): Returns a random hash seed.
emit_event(…): Emits an event with the given event data.
transfer(…): Transfers value from the contract to the destination account ID.
hash_bytes(…): Conducts the crypto hash of the given input and stores the result in output.
- …and many more.