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john edited this page Nov 16, 2018 · 15 revisions

Aion nodes only understand bytecode, and have no idea what to do with Solidity, Python, or Java. Since bytecode isn't very nice to deal with, you can use the Web3 API.

When you make a request to Web3.js it converts it into a JSON RPC process. This abstracts the interaction between your code and the blockchain.

Run through the Tutorial

Want to get your hands dirty and build something straight away? Check out the new Web3 tutorial over at Aion University.

Prerequisites

Make sure the following software is installed locally on your machine before attempting to run Web3.

Git Logo

Node Logo

NPM Logo

Node Access

In order for Web3.js to interact with the blockchain, it needs access to an Aion node. You can set up your own node on your local machine, or connect to a hosting service.

Install

The two main ways to install the Aion Web3.js framework are by using NPM, or by cloning the GitHub repository.

NPM Install

This is the simplest method of installing the Aion Web3.js framework. Just run:

npm install aion-web3

Then just include these two lines at the top of your project:

const Web3 = require('aion-web3')
const web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:8545"));

GitHub Install

This method of installation is a bit more hands on, but allows for more granularity and customization.

Super Quick Installation

Run this one-liner if you're super busy and don't have time to read more than one line:

git clone https://github.com/aionnetwork/aion_web3.git && cd aion_web3 && npm install && node console.js
  1. Clone the aion_web3 repository from Github.
git clone https://github.com/aionnetwork/aion_web3.git
  1. Change directory into the folder you just cloned.
cd aion_web3
  1. Install all the Node.js dependencies.
npm install

You may receive some warning here about certain dependencies and functions being deprecated. This is fine for now. We are working on replacing these dependencies.

  1. Open the Node console to interact with Web3
node console.js
  1. You should now see something like aion-127.0.0.1:8545> in your terminal.

You now have access to Web3.js. From now on, whenever you want to access the API, run node console.js from the aion_web3 directory in a terminal window. However, unless you are connected to a node (a computer node, not Node.js), the is not much you can do.

Connecting to a Node

To change the address of the node that you want to connect to, supply the URL as an argument after calling console.js:

node console.js https://aion-api-endoint.example.com/testnet

Or, for a more permanent solution, edit the following line in console.js:

    var endpoint = process.argv[2] || 'https://aion-api-endoint.example.com/testnet';

The default value is 127.0.0.1:8545.

Testing

To make sure that everything is setup ok, run through the following steps to test your connection to the Aion blockchain:

  1. Open a terminal and run:
node console.js
  1. In the Node console enter:
const high_baller = '0xa022a68ef27e5febe4570edb2ce5586974cb326f24fce2ebb23012c07dac90e0'

This line creates a constant variable called high_baller with a long string as it's value. This long string is the address of a mining group within the Aion network. Once you've entered the variable the console will output something like undefined.

  1. Still in the node console, enter the following:
web3.eth.getBalance(high_baller, (err, bal) => { balance = bal })

This line calls the getBalance() function within the web3 object. The high_baller account is supplied as the first argument, and the result of this function is returned to a variable called balance. Again, once you've entered the variable the console will output something like undefined.

  1. Entering balance will return the amount of NRG that the high_baller account contains:
> balance
'43153146328612172515'
  1. To convert this amount into Aion just run:
web3.utils.fromNAmp(balance, 'aion')

If you ever forget which functions the web3 object contains, just enter web3 into the terminal and it will output a long list of everything that's available to you:

> web3

Web3 {
  currentProvider: [Getter/Setter],
  _requestManager:
   RequestManager {
     provider:

continued...

Obviously, you can also just check out the Aion Web3.js documentation.

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