README.md

EVM ABI Decoder

EVM ABI Decoder allows to decode raw input data from a EVM transaction (on Ethereum or a compatible chain like Avalanche, BSC etc.) into a processable format obtained from the contract's ABi definition (JSON).

Acknowledgement: This project is based on Bryce Neals's project abidecoder (Kotlin), which itself is a port of ConsenSys project abi-decoder (JavaScript).

The original project is written in Kotlin, only published on JitPack (but not on Maven Central) and depends on the now deprecated ethereumj. These were enough reasons for me to rewrite it in Java ;-)

QuickStart

Maven

<dependency>
    <groupId>net.osslabz</groupId>
    <artifactId>evm-abi-decoder</artifactId>
    <version>0.1.0</version>
</dependency>

Usage

Loads the UniswapV2Router02 contract and parses a swap transaction:

// Abi can be found here: https://etherscan.io/address/0x7a250d5630b4cf539739df2c5dacb4c659f2488d#code
AbiDecoder uniswapv2Abi=new AbiDecoder(this.getClass().getResource("/abiFiles/UniswapV2Router02.json").getFile());

// tx: https://etherscan.io/tx/0xde2b61c91842494ac208e25a2a64d99997c382f6aaf0719d6a719b5cff1f8a07
String inputData="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";

/**
 * #  Name          Type       Data
 * ----------------------------------------------------------------------
 * 0  amountIn      uint256    10000000
 * 1  amountOutMin  uint256    6283178947560620
 * 2  path          address[]  0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48
 *                             0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2
 * 3  to            address    0xD4CF8e47BeAC55b42Ae58991785Fa326d9384Bd1
 * 4  deadline      uint256    1659426897
 */

DecodedFunctionCall decodedFunctionCall=uniswapv2Abi.decodeFunctionCall(inputData);

System.out.println(decodedFunctionCall.getName()); // prints swapExactTokensForETH

Logging

This project uses slf4j-api but doesn't package an implementation. This is up to the using application. For the tests logback is backing slf4j as implementation, with a default configuration logging to STOUT.