fancy-blockchain

Directory Structure

|_ contracts
  |__ Fancy.sol
  |__ Migrations.sol
|_ migrations
  |__ 1_initial_migrations.js
  |__ 2_deploy_contracts.js
|_ src
  |__ index.js
|_ truffle-config.js

Description

contracts/ : Directory for Solidity source files of the smart contract

|_ Fancy.sol : a smart contract (written in Solidity) that creates a Fancy token

|_ Migrations.sol : a seperate Solidity file that manages and updates the status of the deployed smart contract

migrations/ : Directory for scriptable deployment files(written in JavaScript)

|_ 1_initial_migrations.js : Migration (deployment) script for the Migrations contract found in the Migrations.sol file

|_ 2_deploy_contracts.js : Migration script for the Fancy contract. (This will be executed after file is runned

contracts/ : Directory for javascript source files of function using caver-js

truffle-config.js : Truffle configuration file for setting network information and other project-related settings

Fancy.sol

event Transfer(uint256 value, address indexed to, address indexed from);

-> Fancy/ERC20/IERC20.sol

-> Emitted when value tokens are moved from one account (from) to another (to).

constructor(string memory name, string memory symbol) public{}

-> Constructor defines a new ERC20 token's name and symbol, and to mint a predefined amount of token.

->The name of the token contract is the long name by which the token contract should be known

->The symbol of the token contract is the symbol by which the token contract should be known

function totalSupply() public view returns(uint256) {}

-> Function which returns the amount of tokens in existence

function balanceOf(address account) public veiw returns(uint256)

function which shows the balance of the account

function transfer(address recipient, uint256 amount) public returns(bool)

function which transfer certain amount of token(_price) from musician to fan if balance of musician should be bigger than the _price. then emit Transfer event

function transferFrom(address sender, address recipient, uint256 amount) public returns(bool)

function which transfer certain amount of token(_price) from musician to fan if balance of musician should be bigger than the _price. then emit Transfer event

function _mint(address account, uint256 amount) internal {}

-> Function that create a new ERC20 tokens. This is invoked only once from constructor when deploying the smart contract to mint a predefined amount of token

-> If additional token is required after deploying the smart contract, a new public method such as mint should be introduced.

-> CAUTION : only authorized users should be able to mint tokens

-> reference : https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/ERC20Mintable.sol

index.js

value

• ERC20ABI : 배포된 Smart Contract ERC20ABI
• contractAddress -> 배포된 Smart Contract Address
• defaultAddress -> 배포된 Smart Contract Address default acount의 address
• defaultPrivateKey -> 배포된 Smart Contract Address default acount의 privatekey
• userAddress -> 로그인 되어있는 해당 유저의 address

App.callContractSupply

-> Total Supply 조회

App.registerAlbum(string userAdd)

-> 앨범 등록 후 토큰 사용자의 계정에 토큰 지급

App.perchaseThing(string userPk, string userAdd)

-> 물건 구매 후 계정의 토큰 차감

App.callBalanceOF(string userAdd)

-> 사용자 계정의 잔고 조회