我刚刚为 ICO 制作了智能合约，现在我需要实现以下功能：
1.用户向钱包发送了一定数量的ETH
2.用户获得一定数量的代币到他的钱包以换取自动发送的ETH
我对这一切都很陌生，所以我想知道 - 是否可以自动执行此操作（或仅在手动模式下？），如果不是使用智能合约本身，也许还有另一种方法可以做到这一点，比如获取事件和使用某种 API（例如 PHP 或 JS）从智能合约调用函数？如果可能的话，我什么时候可以找到有关此的一些信息？只找到了几个这样的问题，但没有答案。
这是合约代码（主要取自这里）：
pragma solidity ^0.4.2;
contract owned {
address public owner;
function owned() {
owner = msg.sender;
}
modifier onlyOwner {
if (msg.sender != owner) return;
_;
}
function transferOwnership(address newOwner) onlyOwner {
owner = newOwner;
}
}
contract tokenRecipient { function receiveApproval(address _from, uint256
_value, address _token, bytes _extraData); }
contract token {
/* Public variables of the token */
string public standard = 'Token 0.1';
string public name;
string public symbol;
uint8 public decimals;
uint256 public totalSupply;
/* This creates an array with all balances */
mapping (address => uint256) public balanceOf;
mapping (address => mapping (address => uint256)) public allowance;
/* This generates a public event on the blockchain that will notify clients
*/
event Transfer(address indexed from, address indexed to, uint256 value);
/* Initializes contract with initial supply tokens to the creator of the
contract */
function token(
uint256 initialSupply,
string tokenName,
uint8 decimalUnits,
string tokenSymbol
) {
balanceOf[msg.sender] = initialSupply; // Give the creator
all initial tokens
totalSupply = initialSupply; // Update total
supply
name = tokenName; // Set the name for
display purposes
symbol = tokenSymbol; // Set the symbol
for display purposes
decimals = decimalUnits; // Amount of
decimals for display purposes
}
/* Send coins */
function transfer(address _to, uint256 _value) {
if (balanceOf[msg.sender] < _value) return; // Check if the
sender has enough
if (balanceOf[_to] + _value < balanceOf[_to]) return; // Check for
overflows
balanceOf[msg.sender] -= _value; // Subtract from
the sender
balanceOf[_to] += _value; // Add the same to
the recipient
Transfer(msg.sender, _to, _value); // Notify anyone
listening that this transfer took place
}
/* Allow another contract to spend some tokens in your behalf */
function approve(address _spender, uint256 _value)
returns (bool success) {
allowance[msg.sender][_spender] = _value;
return true;
}
/* Approve and then communicate the approved contract in a single tx */
function approveAndCall(address _spender, uint256 _value, bytes _extraData)
returns (bool success) {
tokenRecipient spender = tokenRecipient(_spender);
if (approve(_spender, _value)) {
spender.receiveApproval(msg.sender, _value, this, _extraData);
return true;
}
}
/* A contract attempts to get the coins */
function transferFrom(address _from, address _to, uint256 _value) returns
(bool success) {
if (balanceOf[_from] < _value) return; // Check if the
sender has enough
if (balanceOf[_to] + _value < balanceOf[_to]) return; // Check for
overflows
if (_value > allowance[_from][msg.sender]) return; // Check allowance
balanceOf[_from] -= _value; // Subtract from
the sender
balanceOf[_to] += _value; // Add the same to
the recipient
allowance[_from][msg.sender] -= _value;
Transfer(_from, _to, _value);
return true;
}
/* This unnamed function is called whenever someone tries to send ether to
it */
function () {
return; // Prevents accidental sending of ether
}
}
contract MyAdvancedToken is owned, token {
uint256 public sellPrice;
uint256 public buyPrice;
mapping (address => bool) public frozenAccount;
/* This generates a public event on the blockchain that will notify clients
*/
event FrozenFunds(address target, bool frozen);
/* Initializes contract with initial supply tokens to the creator of the
contract */
function MyAdvancedToken(
uint256 initialSupply,
string tokenName,
uint8 decimalUnits,
string tokenSymbol
) token (initialSupply, tokenName, decimalUnits, tokenSymbol) {}
/* Send coins */
function transfer(address _to, uint256 _value) {
if (balanceOf[msg.sender] < _value) return; // Check if the
sender has enough
if (balanceOf[_to] + _value < balanceOf[_to]) return; // Check for
overflows
if (frozenAccount[msg.sender]) return; // Check if frozen
balanceOf[msg.sender] -= _value; // Subtract from
the sender
balanceOf[_to] += _value; // Add the same to
the recipient
Transfer(msg.sender, _to, _value); // Notify anyone
listening that this transfer took place
}
/* A contract attempts to get the coins */
function transferFrom(address _from, address _to, uint256 _value) returns
(bool success) {
if (frozenAccount[_from]) return; // Check if
frozen
if (balanceOf[_from] < _value) return; // Check if the
sender has enough
if (balanceOf[_to] + _value < balanceOf[_to]) return; // Check for
overflows
if (_value > allowance[_from][msg.sender]) return; // Check allowance
balanceOf[_from] -= _value; // Subtract from
the sender
balanceOf[_to] += _value; // Add the same to
the recipient
allowance[_from][msg.sender] -= _value;
Transfer(_from, _to, _value);
return true;
}
function mintToken(address target, uint256 mintedAmount) onlyOwner {
balanceOf[target] += mintedAmount;
totalSupply += mintedAmount;
Transfer(0, this, mintedAmount);
Transfer(this, target, mintedAmount);
}
function freezeAccount(address target, bool freeze) onlyOwner {
frozenAccount[target] = freeze;
FrozenFunds(target, freeze);
}
function setPrices(uint256 newSellPrice, uint256 newBuyPrice) onlyOwner {
sellPrice = newSellPrice;
buyPrice = newBuyPrice;
}
function buy() payable {
uint amount = msg.value / buyPrice; // calculates the
amount
if (balanceOf[this] < amount) return; // checks if it has
enough to sell
balanceOf[msg.sender] += amount; // adds the amount to
buyer's balance
balanceOf[this] -= amount; // subtracts amount
from seller's balance
Transfer(this, msg.sender, amount); // execute an event
reflecting the change
}
function sell(uint256 amount) {
if (balanceOf[msg.sender] < amount ) return; // checks if the
sender has enough to sell
balanceOf[this] += amount; // adds the amount to
owner's balance
balanceOf[msg.sender] -= amount; // subtracts the
amount from seller's balance
if (!msg.sender.send(amount * sellPrice)) { // sends ether to the
seller. It's important
return; // to do this last
to avoid recursion attacks
} else {
Transfer(msg.sender, this, amount); // executes an event
reflecting on the change
}
}
}
请原谅我可能的愚蠢和糟糕的英语:)
非常感谢。