luke-unicorn / augur-abi

ABI encoder for Serpent contracts

augur-abi

augur-abi is a standalone JavaScript module that provides Ethereum contract ABI data serialization methods. ABI encoding is needed to invoke functions on Ethereum smart contracts.

This module presently supports only Serpent contracts; it's my intention to add Solidity data type support when I have time!

Installation

$ npm install augur-abi

Usage

To use augur-abi in Node.js, just require it:

var augur_abi = require("augur-abi");

A minified, browserified file dist/augur-abi.min.js is included for use in the browser. Including this file simply attaches the augur_abi object to window:

<script src="dist/augur-abi.min.js" type="text/javascript"></script>

The encode method encodes the full ABI data (prefix + parameters) needed for a contract function call. For example, to encode a method named double that takes a single integer parameter with a value of 3:

var encoded = augur_abi.encode({
    method: "double",
    signature: "i",
    params: [3]
});
// encoded:
'0x6ffa1caa0000000000000000000000000000000000000000000000000000000000000003'

encoded is the concatenation of the method's prefix 0x6ffa1caa, which is derived from the name of the method "double" and its signature "i", and the encoded parameter value, [3].

"Signature" refers to the short-form Serpent parameter signature, which allows i (int256), a (variable-sized int256 array) and s (variable-length string/bytes). For example, a method which takes parameter types int256, string, int256, int256, int256, array would have signature isiiia.

Tests

Unit tests are in the test directory, and can be run with mocha:

$ npm test