Afin d’eviter que le createur d’un kickstarter ne s’enfuie avec la caisse comme cela est deja arrivé a de nombreuses reprises nous allons coder un smartcontract qui recevra les fonds des investisseurs et qui autorisera le createur du kickstarter a utiliser les fonds du projet uniquement pour les “bonnes raisons”
Le createur devra faire une requête pour dépenser les fonds du contrat , ce seront les investisseurs qui auront le pouvoir de voter OUI ou NON pour la dépense
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;
contract Campaign {
struct Request {
string description;
uint value;
address recipient;
bool complete;
// keeps track of the "yes" vote
uint approvalCount;
// people who have provided approval for the request
mapping(address=>bool) approvals;
}
// index of the request
uint numRequest;
// requests created by the manager
mapping (uint=>Request) public requests;
// address of the Campaign creator
address public manager;
// minimumContribution to be considerer a contributor or validator , set in the constructor
uint public minimumContribution;
// number of people who contributed
uint numberOfApprovers;
// people who contributed to the campaign
mapping(address=>bool) public approvers;
modifier OnlyManager() {
require(msg.sender == manager);
_;
}
constructor(uint minimum) {
manager = msg.sender;
minimumContribution = minimum;
}
// Contribute to a Campaign
function contribute() public payable {
require(msg.value > minimumContribution);
numberOfApprovers++;
approvers[msg.sender] = true;
}
// Manager can create a spending request
function createRequest(string memory description, uint value, address recipient) public OnlyManager {
Request storage r = requests[numRequest++];
r.description = description;
r.value = value;
r.recipient= recipient;
r.complete = false;
r.approvalCount=0;
}
// called by each contributor to approve a spending request
function approveRequest(uint requestId) public {
Request storage request = requests[requestId];
// we need to make sure that the person is an approver
require(approvers[msg.sender]);
// we need to make sure that the person has not already approved it !
require(!request.approvals[msg.sender]);
// mark that this person just voted for this request
request.approvals[msg.sender]=true;
// add one to approvalCount
request.approvalCount++;
// update the approvals mapping in request struct
request.approvals[msg.sender] = true;
// tell that msg.sender address has voted
approvers[msg.sender] = true;
}
// after a request has gotten enough approval, the manager can call this to get
// money sent to the vendor
function finalizeRequest(uint requestId) public OnlyManager {
Request storage r = requests[requestId];
// make sure that the request has enough approvals
// le nombre d'approvals de la request > a la moitié du nombre de votants
require(r.approvalCount > (numberOfApprovers/2));
// set complete status of the request at true
r.complete = true;
// sends the "value" to the "destination" property of the request
payable(r.recipient).transfer(r.value);
}
}