Ethereum Event Analysis #04: SWAP Data Parsing

Background

Parsing trading pair data is a crucial and frequent requirement in blockchain projects. Whether analyzing decentralized exchanges (DEX) like Uniswap on Ethereum (ETH) or PancakeSwap on Binance Smart Chain (BSC), the underlying logic for trading pair parsing remains fundamentally identical. This consistency allows us to modularize trading pair services, enhancing both code reusability and system maintainability.

During module development, we integrated pre- and post-event processing interfaces (Handler files) to enable flexible business system integration. For instance:

Developers can validate data via preprocessing interfaces before event execution
Post-processing interfaces allow modification of parsed results post-event

This design aligns with framework requirements while ensuring high adaptability across multi-chain environments (e.g., supporting other DEX protocols). The standardized code structure also establishes a foundation for future scalability.

Contract Address Mechanism

// Factory call
function getPair(address tokenA, address tokenB) external view returns (address pair);

// Algorithmic derivation
keccak256(
  abi.encodePacked(
    hex"ff",
    factoryAddress,
    keccak256(abi.encodePacked(tokenA, tokenB)),
    initCodeHash
  )
)

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Data Structures

Configuration Data

Initially, pair configurations weren't standardized, leading to the use of extension fields for address specifications. Below exemplifies the DML implementation:

INSERT INTO `t_contract_config` (`contract_config_id`, `chain_config_id`, `chain_symbo

Core Concepts Explained

Modular Design Benefits
- Unified parsing logic across chains
- Pre/post handlers for custom workflows
- Framework-compliant structure
Pair Address Derivation
- Factory contract interactions
- Deterministic address calculation
Configuration Management
- Retrospective field utilization
- Chain-specific adaptations

FAQ Section

Q1: How does pair address calculation ensure uniqueness?
A: The algorithm combines factory address, token pair hash, and chain-specific initCodeHash to create deterministic, non-colliding addresses.

Q2: Can this module support new DEX protocols easily?
A: Yes, the handler interface system allows protocol-specific adaptations without core logic modifications.

Q3: Why use database fields for pair configuration?
A: This provided temporary flexibility before native configuration systems were implemented.

Q4: What's the advantage of standardized code structure?
A: It enables team collaboration efficiency and reduces onboarding time for new developers.

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