为了实现一个区块链带货系统，通过分享二维码自动获得返佣，并将所有逻辑写在智能合约中，我们需要以下几个步骤：

1. 智能合约设计：定义用户注册、订单记录和返佣逻辑。
2. 二维码生成：生成带有推荐人标识的二维码。
3. 前端与智能合约交互：用户通过二维码注册和下单，触发智能合约中的逻辑。

智能合约设计

我们使用Solidity编写一个简单的智能合约，部署在以太坊或其他兼容EVM的区块链上。

智能合约示例

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract ReferralMarketing {
    struct User {
        address referrer;
        uint256 commission;
        bool registered;
    }

    mapping(address => User) public users;
    mapping(bytes32 => uint256) public orders;

    event UserRegistered(address user, address referrer);
    event OrderPlaced(address user, bytes32 orderId, uint256 amount);
    event CommissionPaid(address referrer, uint256 amount);

    function registerUser(address referrer) external {
        require(!users[msg.sender].registered, "User already registered");

        users[msg.sender] = User({
            referrer: referrer,
            commission: 0,
            registered: true
        });

        emit UserRegistered(msg.sender, referrer);
    }

    function placeOrder(bytes32 orderId, uint256 amount) external {
        require(users[msg.sender].registered, "User not registered");
        require(orders[orderId] == 0, "Order already exists");

        orders[orderId] = amount;

        emit OrderPlaced(msg.sender, orderId, amount);

        // Calculate and distribute commission
        address referrer = users[msg.sender].referrer;
        if (referrer != address(0)) {
            uint256 commission = amount * 5 / 100; // 5% commission
            users[referrer].commission += commission;

            emit CommissionPaid(referrer, commission);
        }
    }

    function withdrawCommission() external {
        uint256 commission = users[msg.sender].commission;
        require(commission > 0, "No commission to withdraw");

        users[msg.sender].commission = 0;
        payable(msg.sender).transfer(commission);
    }

    // Function to receive Ether. msg.data must be empty
    receive() external payable {}

    // Fallback function is called when msg.data is not empty
    fallback() external payable {}
}

二维码生成

使用Python生成带有推荐人地址的二维码。

import qrcode

def generate_qr_code(referrer_address):
    url = f"http://example.com/register?referrer={referrer_address}"
    
    qr = qrcode.QRCode(
        version=1,
        error_correction=qrcode.constants.ERROR_CORRECT_L,
        box_size=10,
        border=4,
    )
    qr.add_data(url)
    qr.make(fit=True)
    
    img = qr.make_image(fill='black', back_color='white')
    img.save(f"{referrer_address}_qrcode.png")
    print(f"QR code for {referrer_address} generated.")

# Example usage
if __name__ == "__main__":
    generate_qr_code('0xYourReferrerAddress')

前端与智能合约交互

使用Web3.js或Ethers.js与智能合约交互，以下是一个简单的Web3.js示例：

    
    


    
Referral Marketing
    Register
    Place Order
    

总结

通过上述步骤，我们实现了一个简单的区块链带货系统，用户通过二维码注册和下单，智能合约自动记录订单并计算返佣。这个系统利用区块链技术确保所有操作的透明性和不可篡改性，同时自动化了返佣流程。