This example contains a src folder and the Cargo.toml file.
The src folder contains several Rust smart contracts, which are then imported into contract.rs.
The functionality present in contract.rs is derived from other contracts, creating a system where certain features can be inherited.
The structure of these contracts draws inspiration from the existing contract structure of fungible tokens in Soroban, as there is no established standard to follow for NFTs.
To adapt this for NFTs, we have made some modifications and introduced functions to enhance each contract's capabilities.
admin.rs
- has_administrator(env: &Env) -> bool: Checks if the system has an administrator by querying the storage using a specific key.
- read_administrator(env: &Env) -> Identifier: Reads and returns the administrator's identifier from the system's storage.
- write_administrator(env: &Env, id: Identifier): Writes the provided administrator's identifier to the system's storage.
- check_admin(env: &Env, auth: &Signature): Verifies if a given authentication signature corresponds to the system's administrator by comparing the identifier from the signature with the one stored in the system's storage.
- In summary, these functions enable checking for the existence of an administrator, managing the administrator's identifier in the system's storage, and ensuring that specific actions are authorized by the system's administrator.
approval.rs
- read_approval(env: &Env, id: i128) -> Identifier: Reads and returns the approval identifier for a specific action with the given id. If the approval doesn't exist, it returns a default "zero address" identifier.
- read_approval_all(env: &Env, owner: Identifier, operator: Identifier) -> bool: Checks if a specific operator has approval from a specific owner for all actions. It returns true if the approval exists, indicating the operator has approval; otherwise, it returns false.
- write_approval(env: &Env, id: i128, operator: Identifier): Writes the approval identifier for a specific action with the given id and operator to the system's storage.
- write_approval_all(env: &Env, owner: Identifier, operator: Identifier, approved: bool): Writes the approval status (approved or not) for all actions from a specific owner to a specific operator in the system's storage.
balance.rs
- read_balance(env: &Env, owner: Identifier) -> i128: Reads and returns the balance of a specific owner in the system. If the balance doesn't exist, it returns 0.
- write_balance(env: &Env, owner: Identifier, write_type: WriteType): Writes the balance of a specific owner in the system based on the provided write_type (add or remove).
- read_supply(env: &Env) -> i128: Reads and returns the total supply in the system. If the supply doesn't exist, it returns 0.
- increment_supply(env: &Env): Increments the total supply in the system by 1.
- read_minted(env: &Env, owner: Identifier) -> bool: Reads and returns whether the specific owner has been minted. If not minted, it returns false.
- write_minted(env: &Env, owner: Identifier): Sets the minted status for the specific owner to true.
- check_minted(env: &Env, owner: Identifier): Checks if the specific owner has already been minted and panics with an error message if it has.
contract.rs
- This is the main function which uses imported functionalities of other contracts and it holds the all basic functions of nft. From minting to transfer(xfer) of the nft contract.rs is responsible. You will find all basic functions like ERC721 standard.
event.rs
- transfer(e: &Env, from: Identifier, to: Identifier, id: i128): Publishes a transfer event with the sender (from) and receiver (to) information along with the id of the transfer.
- set_admin(e: &Env, admin: Identifier, new_admin: Identifier): Publishes a set_admin event with the current administrator (admin) information, notifying that a new administrator (new_admin) has been set.
- mint(e: &Env, to: Identifier, id: i128): Publishes a mint event with the receiver (to) information and the id of the mint operation.
- burn(e: &Env, from: Identifier, id: i128): Publishes a burn event with the owner (from) information and the id of the burn operation.
- approve(e: &Env, operator: Identifier, id: i128): Publishes an approval event with the approved operator (operator) information and the id of the approval.
- approve_all(e: &Env, operator: Identifier, owner: Identifier): Publishes an approval event for all actions with the approved operator (operator) and the owner's (owner) information.
- In summary, these functions allow the system to notify and record events related to transfers, setting administrators, minting, burning, and approvals.
interface.rs
- This file has been well explained over the code itself.
lib.rs
- Modular implementation for a Non-Fungible Token (NFT) system designed for environments.
metadata.rs
- read_name(env: &Env) -> Bytes: Reads and returns the token name from the system's storage. write_name(env: &Env, name: Bytes): Writes the provided token name to the system's storage.
- read_symbol(env: &Env) -> Bytes: Reads and returns the token symbol from the system's storage.
- write_symbol(env: &Env, symbol: Bytes): Writes the provided token symbol to the system's storage.
- read_token_uri(env: &Env, id: i128) -> Bytes: Reads and returns the URI (Uniform Resource Identifier) associated with the token ID from the system's storage.
- write_token_uri(env: &Env, id: i128, uri: Bytes): Writes the provided URI for the given token ID to the system's storage.
owner.rs
- zero_address(env: &Env) -> Identifier: Returns a default Identifier representing a zero address. This function is used as a placeholder for non-existent or unspecified owners.
- read_owner(env: &Env, id: i128) -> Identifier: Reads and returns the owner's identifier for a specific token id from the system's storage. If the owner doesn't exist, it returns the default zero address.
- write_owner(env: &Env, id: i128, owner: Identifier): Writes the owner's identifier for a specific token id to the system's storage.
- check_owner(env: &Env, auth: &Identifier, id: i128): Checks if a given auth identifier matches the owner's identifier for a specific token id. It panics with an error message if the auth identifier doesn't match the owner's identifier.
storage_types.rs
- This code defines contract types (ApprovalAll, ApprovalKey, and DataKey) used for managing approvals and data keys in the system. Here's a summary of each contract type:
- ApprovalAll: Represents a combination of an operator and an owner identifier for approvals.
- ApprovalKey: An enum representing different types of approval keys: either All(ApprovalAll) or ID(i128).
- DataKey: An enum representing different types of data keys used in the system, such as Balance, Nonce, Minted, Admin, Name, Symbol, URI, Approval, and Owner.
Each contract type is derived with the Clone trait and annotated with #[contracttype].
These contract types provide a structured way to manage approvals and access data keys within the system.
- Setup soroban-cli following the steps mentioned on this page - https://soroban.stellar.org/docs/getting-started/setup
- If you are a Windows user that wants to leverage Linux please refer to this video as a guide - (https://www.youtube.com/watch?v=PQA5_7m3OjQ&t=2s)
- After the setup and installation of soroban-cli, run the command
soroban contract build- After the code compilation, you will see a newly created folder named ‘target’ which contains the wasm executable.