iTerm2 Web3 Wallet Extension

A browser extension that provides Web3 wallet functionality for iTerm2's Browser using Foundry Cast as the backend.

Architecture

This extension consists of:

Browser Extension: Provides window.ethereum interface to web pages
Cast HTTP Server: Modified Foundry Cast tool with JSON-RPC HTTP server
Transaction UI: In-page confirmation modals for transaction approval

Components

Extension Files

manifest.json - Extension manifest (Manifest V3)
background.js - Service worker handling Cast communication
content-script.js - Injects window.ethereum provider into web pages
confirmation-modal.html - Transaction confirmation UI
confirmation-modal.css - Styling for confirmation modal

Background Script (`background.js`)

Handles:

Communication with Cast HTTP server on localhost:8545
Translation between Web3 JSON-RPC and Cast commands
Basic wallet operations (accounts, balance, transactions)

Content Script (`content-script.js`)

Provides:

EIP-1193 compliant window.ethereum provider
Legacy Web3 compatibility methods
Event handling for account/network changes

Confirmation Modal

Native in-page transaction confirmation
Shows transaction details, gas estimates, fees
User approval/rejection handling

Installation

Prerequisites

Modified Cast Tool: Fork Foundry Cast with HTTP server support
iTerm2 Browser: Latest version with WebExtensions support

Steps

Install Modified Cast:

# Build cast with HTTP server support
git clone [cast-fork-repo]
cd foundry
cargo build --release --bin cast
cp target/release/cast /usr/local/bin/cast-web3

Start Cast HTTP Server:
```
cast-web3 --http-server --port 8545
```
Install Extension:
- Copy extension folder to iTerm2 extensions directory
- Enable in iTerm2 Browser settings

Usage

Starting the Wallet

Start Cast HTTP server:
```
cast-web3 --http-server
```

Create or import wallet:

cast-web3 wallet new  # Create new wallet
# or
cast-web3 wallet import --private-key 0x...  # Import existing

Extension automatically connects to Cast server

Web3 dApp Integration

The extension provides a standard window.ethereum interface:

// Connect to wallet
const accounts = await ethereum.request({ method: 'eth_requestAccounts' });

// Get balance
const balance = await ethereum.request({ 
  method: 'eth_getBalance',
  params: [accounts[0], 'latest'] 
});

// Send transaction
const txHash = await ethereum.request({
  method: 'eth_sendTransaction',
  params: [{
    from: accounts[0],
    to: '0x...',
    value: '0x1000000000000000000' // 1 ETH in wei
  }]
});

Supported Web3 Methods

Account Management

eth_requestAccounts - Connect wallet
eth_accounts - Get connected accounts

Network Information

eth_chainId - Get current chain ID
net_version - Get network version

Balance & Transactions

eth_getBalance - Get account balance
eth_sendTransaction - Send transaction
eth_call - Call contract method
eth_estimateGas - Estimate gas for transaction

Cast HTTP Server Modifications

The extension requires a modified version of Foundry Cast with HTTP server support:

New Cast Commands

cast --http-server - Start JSON-RPC HTTP server
cast wallet list - List available accounts (JSON)
Additional JSON output modes for all commands

HTTP Endpoints

POST / - JSON-RPC endpoint for all Cast operations
GET /health - Server health check

Command Mapping

eth_getBalance → cast balance
eth_sendTransaction → cast send
eth_call → cast call
eth_chainId → cast chain-id

Development

File Structure

web3-wallet-extension/
├── manifest.json
├── background.js
├── content-script.js
├── confirmation-modal.html
├── confirmation-modal.css
└── README.md

Testing

Load extension in iTerm2 Browser
Navigate to a Web3 dApp (e.g., Uniswap)
Connect wallet and test transactions

Debugging

Check browser console for Web3 provider logs
Monitor Cast server logs for RPC requests
Use iTerm2's extension debugging tools

Security Considerations

Extension runs in isolated context
Private keys managed by Cast (not extension)
Transaction confirmation required for all sends
No automatic transaction approvals

Future Enhancements

Hardware wallet support via Cast
Multi-network switching
Transaction history
Gas optimization
dApp permissions system

sambacha/cast-iterm2