Created
November 4, 2017 22:10
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ETH tutorial crowdsale
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pragma solidity ^0.4.16; | |
interface token { | |
function transfer(address receiver, uint amount); | |
} | |
contract Crowdsale { | |
address public beneficiary; | |
uint public fundingGoal; | |
uint public amountRaised; | |
uint public deadline; | |
uint public price; | |
token public tokenReward; | |
mapping(address => uint256) public balanceOf; | |
bool fundingGoalReached = false; | |
bool crowdsaleClosed = false; | |
event GoalReached(address recipient, uint totalAmountRaised); | |
event FundTransfer(address backer, uint amount, bool isContribution); | |
/** | |
* Constrctor function | |
* | |
* Setup the owner | |
*/ | |
function Crowdsale( | |
address ifSuccessfulSendTo, | |
uint fundingGoalInEthers, | |
uint durationInMinutes, | |
uint etherCostOfEachToken, | |
address addressOfTokenUsedAsReward | |
) { | |
beneficiary = ifSuccessfulSendTo; | |
fundingGoal = fundingGoalInEthers * 1 finney; | |
deadline = now + durationInMinutes * 1 minutes; | |
price = etherCostOfEachToken * 1 finney; | |
tokenReward = token(addressOfTokenUsedAsReward); | |
} | |
/** | |
* Fallback function | |
* | |
* The function without name is the default function that is called whenever anyone sends funds to a contract | |
*/ | |
function () payable { | |
require(!crowdsaleClosed); | |
uint amount = msg.value; | |
balanceOf[msg.sender] += amount; | |
amountRaised += amount; | |
tokenReward.transfer(msg.sender, amount / price); | |
FundTransfer(msg.sender, amount, true); | |
} | |
modifier afterDeadline() { if (now >= deadline) _; } | |
/** | |
* Check if goal was reached | |
* | |
* Checks if the goal or time limit has been reached and ends the campaign | |
*/ | |
function checkGoalReached() afterDeadline { | |
if (amountRaised >= fundingGoal){ | |
fundingGoalReached = true; | |
GoalReached(beneficiary, amountRaised); | |
} | |
crowdsaleClosed = true; | |
} | |
/** | |
* Withdraw the funds | |
* | |
* Checks to see if goal or time limit has been reached, and if so, and the funding goal was reached, | |
* sends the entire amount to the beneficiary. If goal was not reached, each contributor can withdraw | |
* the amount they contributed. | |
*/ | |
function safeWithdrawal() afterDeadline { | |
if (!fundingGoalReached) { | |
uint amount = balanceOf[msg.sender]; | |
balanceOf[msg.sender] = 0; | |
if (amount > 0) { | |
if (msg.sender.send(amount)) { | |
FundTransfer(msg.sender, amount, false); | |
} else { | |
balanceOf[msg.sender] = amount; | |
} | |
} | |
} | |
if (fundingGoalReached && beneficiary == msg.sender) { | |
if (beneficiary.send(amountRaised)) { | |
FundTransfer(beneficiary, amountRaised, false); | |
} else { | |
//If we fail to send the funds to beneficiary, unlock funders balance | |
fundingGoalReached = false; | |
} | |
} | |
} | |
} |
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