Implement MagicSpend on SOCKET

"MagicSpend: Spend Now, Debit Later" allows users to spend assets immediately while deferring the debit process. SOCKET's chain-abstraction architecture is well-suited to facilitate this by combining offchain agents and onchain contracts.

Implementation Steps

Step 1: Immediate Spending Logic

• The MagicSpendAppGateway listens for user spend requests to execute the immediate transaction.
• Returns a confirmation to the user.

Click to expand code snippet

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

contract MagicSpendAppGateway {
    (...)
    mapping(address => uint256) public balances;

    event Spend(address indexed user, uint256 amount);

    function spendNow(address user, uint256 amount) external {
        require(balances[user] >= amount, "Insufficient balance");
        balances[user] -= amount;
        emit Spend(user, amount);
    }
}

Step 2: Deferred Debit Mechanism

• The AppGateway schedules the debit in the EVMx.
• The Watcher monitors the scheduled time.
• When the time arrives, the Watcher triggers a proof for the Switchboard.
• The Smart Contract executes the debit from the user’s account.

Click to expand code snippet

contract MagicSpendAppGateway {
    (...)
    struct DebitSchedule {
        uint256 amount;
        uint256 executeAt;
        bool executed;
    }

    mapping(address => DebitSchedule) public schedules;

    event DebitScheduled(address indexed user, uint256 amount, uint256 executeAt);
    event DebitExecuted(address indexed user, uint256 amount);

    function scheduleDebit(address user, uint256 amount, uint256 delay) external {
        schedules[user] = DebitSchedule(amount, block.timestamp + delay, false);
        emit DebitScheduled(user, amount, block.timestamp + delay);
    }

    function executeDebit(address user) external {
        require(block.timestamp >= schedules[user].executeAt, "Too early");
        require(!schedules[user].executed, "Already executed");

        schedules[user].executed = true;
        emit DebitExecuted(user, schedules[user].amount);
    }
}

Key Considerations

Security Measures

• Onchain State Validation: Before allowing a spend, check balances using read() functions.
• Fraud Prevention: Implement signature verifications in Switchboard.
• Failover Handling: Define fail-safe conditions if a scheduled debit fails (e.g., fallback mechanisms, notifications).

Handling Async Operations

• Use the async modifier in MagicSpendAppGateway to manage multiple chained operations efficiently.
• Implement callback-based promises to synchronize transactions with user accounts.

What's next!

By leveraging SOCKET’s architecture, MagicSpend can be implemented securely and efficiently, ensuring users can spend assets immediately while managing debits asynchronously.

Key Use Cases

Read more about other usecases SOCKET enables

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