UniswapV2 Price Oracle Contract

A robust Solidity smart contract implementation for fetching real-time token prices from UniswapV2 pairs.

Technical Overview

The UniswapV2PriceOracle contract provides price discovery functionality for any ERC20 token that has a liquidity pair with WETH on UniswapV2. The contract uses reserve ratios from liquidity pools to calculate token prices.

Key Features

• Single token price queries
• Batch token price queries
• Price calculations in both token/ETH and ETH/token ratios
• Automatic decimal handling for different token standards
• Event emission for price updates

Core Functions

1. getPairAddress(address tokenA, address tokenB)

   • Returns the UniswapV2 pair address for given token pairs
   • View function that queries the UniswapV2Factory

2. getTokenPrice(address token)

   • Returns tuple of (tokenPrice, ethPrice, symbol)
   • Handles decimal normalization
   • Emits PriceUpdated event
   • Returns prices in 18 decimal precision

3. getMultipleTokenPrices(address[] tokens)

   • Batch processing function for multiple tokens
   • Returns arrays of prices and symbols
   • Gas-efficient implementation for multiple queries

Architecture

The contract interfaces with:

• IUniswapV2Factory: For pair address discovery
• IUniswapV2Pair: For accessing pool reserves
• IERC20: For token metadata (decimals, symbols)

Price Calculation Methodology

Prices are calculated using the following formula:

• Token/ETH price = (reserve_token * 10^18) / reserve_eth
• ETH/Token price = (reserve_eth * 10^token_decimals) / reserve_token

Technical Requirements

• Solidity ^0.8.27
• UniswapV2 compatible network
• WETH token address
• UniswapV2 Factory address

Deployment

The contract requires two constructor parameters:

1. WETH address
2. UniswapV2 Factory address

Security Considerations

• Relies on UniswapV2 liquidity for accuracy
• No price manipulation protection
• Uses instantaneous prices (no TWAP)
• External calls to token contracts

Future Enhancements

• Add TWAP functionality
• Implement price manipulation protection
• Support more token standards
• Add batch token price queries

Contribution

1. Fork the repository
2. Create your feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a pull request

License

This project is licensed under the MIT License - see the LICENSE file for details.