InvestInGas Relayer v2

The InvestInGas Relayer is a critical infrastructure component that connects the frontend, the Uniswap v4 Hook (on Sepolia), and the Sui Gas Oracle. It enables users to purchase gas futures with signatures rather than direct contract interaction, providing a seamless UX.

🏗 Architecture

graph LR
    User[User / Frontend] -- 1. Sign Intent --> Relayer
    Relayer -- 2. Read Gas Price --> SuiOracle[Sui Oracle]
    Relayer -- 3. Execute Trade --> Hook["InvestInGasHook (Sepolia)"]
    Relayer -- 4. Bridge Funds --> LiFi["LiFi Bridge"]

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Source Code (src/)

index.ts

The main entry point for the Relayer service.

• Express Server: Hosts the API endpoints for the frontend.
• Transaction Orchestration: Manages the flow from user intent (signature) to on-chain execution.
• Security: Verifies EIP-712 signatures before submitting transactions.
• CORS & Middleware: Configured for cross-origin requests from the frontend.

evm-client.ts

The interface for interacting with the EVM-based smart contracts.

• Hook Interaction: Calls purchasePosition and redeemPosition on the InvestInGasHook.
• EIP-712 Verification: Contains logic to recover signers from user purchase/redeem intents.
• Position Tracking: Efficiently fetches and filters NFT positions for specific users.

lifi-client.ts

Integrates with the LiFi SDK to handle cross-chain logistics.

• Quote Selection: Fetches optimal bridging quotes for delivering native gas to target chains.
• Calldata Generation: Generates the necessary low-level data for the LiFiBridger to execute cross-chain swaps.
• Same-Chain Detection: Intelligently handles "redemptions" to the same chain without unnecessary bridging.

sui-reader.ts

The bridge to the Sui Gas Oracle.

• Dynamic Field Lookup: Reads real-time gas price data from the Sui Table storage.
• Format Conversion: Converts raw wei values (u128) from Sui into human-readable gwei for the frontend.
• Multi-Chain Aggregation: Fetches and aggregates prices for all supported EVM chains in one call.

🚀 Quick Start

1. Prerequisites

• Node.js v18+
• Wallet with Sepolia ETH (for gas fees).
• Deployed InvestInGasHook and LiFiBridger contracts.
• Valid Sui Oracle Object ID (deployed on Sui Testnet).

2. Installation

# Install dependencies
npm install

# Build the project
npm run build

3. Configuration

Copy the example environment file:

cp .env.example .env

Edit .env and fill in the required values:

EVM_RPC_URL=https://sepolia.infura.io/v3/YOUR_KEY
RELAYER_PRIVATE_KEY=your_private_key_here

HOOK_ADDRESS=0x...      
BRIDGER_ADDRESS=0x...   

SUI_NETWORK=testnet
SUI_ORACLE_OBJECT_ID=0x... 

4. Running the Relayer

npm start

# For development (auto-reload)
npm run dev

📡 API Endpoints

Endpoint	Method	Description
Health
/health	GET	Check relayer status, version, and authorization
Market Data
/api/prices	GET	Fetch all gas prices from Sui Oracle
/api/prices/:chain	GET	Fetch specific chain price and staleness check
/api/lifi/chains	GET	List all chains supported for cross-chain delivery
/api/lifi/quote	GET	Get a bridge quote for a specific redemption
User Data
/api/positions/:user	GET	List user's active/expired gas positions
/api/positions/token/:id	GET	Get detailed data for a specific position ID
Actions
/api/purchase	POST	Execute a purchase (requires signature)
/api/redeem	POST	Redeem a position (requires signature)

🔐 Authorization

For the relayer to work, the wallet associated with RELAYER_PRIVATE_KEY must be authorized on the Hook contract.

Fix: Call setRelayer(YOUR_RELAYER_ADDRESS) on the InvestInGasHook contract using the contract owner's wallet.