When connecting to MetaMask, a DApp can request various permissions to interact with the user's Ethereum accounts and the blockchain. Below are the key permissions and how to request them.

1. Requesting Account Access

To access the user's Ethereum accounts, the DApp can use the eth_requestAccounts method. This method prompts the user to connect their wallet and approve access.

async function requestAccountAccess() {
    if (typeof window.ethereum !== 'undefined') {
        try {
            const accounts = await window.ethereum.request({ method: 'eth_requestAccounts' });
            console.log('Connected account:', accounts[0]);
        } catch (error) {
            console.error('User  denied account access:', error);
        }
    } else {
        console.log('MetaMask is not installed. Please install it to use this DApp.');
    }
}

2. Requesting Network Access

If your DApp needs to access specific networks, you can request permissions using the wallet_requestPermissions method. This allows you to specify the required permissions in the request.

async function requestNetworkAccess() {
    const permissions = [
        {
            eth_accounts: {}
        },
        {
            // Example of requesting network access
            'endowment:network-access': {}
        }
    ];

    try {
        const grantedPermissions = await window.ethereum.request({
            method: 'wallet_requestPermissions',
            params: [permissions],
        });
        console.log('Granted permissions:', grantedPermissions);
    } catch (error) {
        console.error('Permission request denied:', error);
    }
}

3. Handling Dynamic Permissions

Some permissions can be requested dynamically during the DApp's operation. For example, if you need to send a transaction, you can request the necessary permissions at that moment.

async function sendTransaction() {
    const transactionParameters = {
        to: '0xRecipientAddress', // Required
        from: '0xYourAddress', // Must match user's active account
        value: '0x29a2241af62c0000', // 0.1 ETH in wei
        gas: '0x5208', // 21000 Gwei
    };

    try {
        const txHash = await window.ethereum.request({
            method: 'eth_sendTransaction',
            params: [transactionParameters],
        });
        console.log('Transaction sent with hash:', txHash);
    } catch (error) {
        console.error('Transaction failed:', error);
    }
}

Conclusion

By requesting the appropriate permissions, your DApp can securely interact with the user's Ethereum accounts and the blockchain. Always ensure to handle user permissions gracefully and provide clear feedback to users.