ERC-721

This is an ERC-721 Token implementation.

Warning

This contract is an example. It is neither audited nor endorsed for production use. Do not rely on it to keep anything of value secure.

Overview

This contract demonstrates how to build non-fungible or unique tokens using ink!.

Error Handling

Any function that modifies the state returns a Result type and does not changes the state if the Error occurs. The errors are defined as an enum type. Any other error or invariant violation triggers a panic and therefore rolls back the transaction.

Token Management

After creating a new token, the function caller becomes the owner. A token can be created, transferred, or destroyed.

Token owners can assign other accounts for transferring specific tokens on their behalf. It is also possible to authorize an operator (higher rights) for another account to handle tokens.

Token Creation

Token creation start by calling the mint(&mut self, id: u32) function. The token owner becomes the function caller. The Token ID needs to be specified as the argument on this function call.

Token Transfer

Transfers may be initiated by:

• The owner of a token
• The approved address of a token
• An authorized operator of the current owner of a token

The token owner can transfer a token by calling the transfer or transfer_from functions. An approved address can make a token transfer by calling the transfer_from function. Operators can transfer tokens on another account's behalf or can approve a token transfer for a different account.

Token Removal

Tokens can be destroyed by burning them. Only the token owner is allowed to burn a token.