Welcome to this quick start guide to developing applications on the Vechain Thor blockchain platform.

The purpose of this guide is to serve as a quick way to set up your developer environment by installing all the needed tools to develop dApps on the Vechain platform. You will get a good understanding how the various components work together.

Interacting with the blockchain

When you want to call a function on a smart contract, you need to query one of the Vechain hor Nodes and tell it:

• The address of the smart contract.
• The function you want to call.
• The variable you want to send to that function.

To communicate with the Nodes we need to use the RESTful API. Thorify is an application that extends on web3 to allow us to directly communicate with the RESTful API.

Install nodejs

sudo apt-get install nodejs

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sudo apt-get install npm

install web3

sudo apt-get install git

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npm install web3

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npm install --save thorify

asu

Installing VS Code

To write code we need an IDE (Integrated development environment)

https://linuxize.com/post/how-to-install-visual-studio-code-on-ubuntu-18-04/

Setting up your own Local VechainThor Node

See the official installation guide on https://github.com/vechain/thor.

• Please see this guide on how to set up your own Thor Node using Docker.
• Please see this guide on how to set up your own Thor Node on Amazon Cloud.

Creating Smart Contracts

Smart contracts on the Vechain Thor blockchain are run on the Ethereum Virtual Machine, a lightweight operating system that is specially created to run smart contracts.

Solidity is a programming language with a syntax similar to JavaScript that allows programmers to create smart contracts. Popular programs to write smart contracts are Truffle and Remix.

Smart contracts are deployed by sending a transaction to the blockchain in which the receiver address is empty and the data field contains the compiled code of the contract to be created.

To communicate with the Nodes to for example send a transaction and to deploy a contract we need to use Thor’s RESTful API. Web3-Gear is an application developed to allow Truffle and Remix to communicate with Thor’s RESTful API. It converts Ethereum RPC calls to VechainThor RPC calls.

How to install web3-Gear

To install web3-Gear we first have to install its dependencies LibSSL and Python

sudo apt-get install libssl-dev

Install the Python installer pip by running

sudo apt install python3-pip

After this we can install Web3-Gear and it’s dependent Python packages via Pypi

pip3 install web3-gear

Run and Setup web3-Gear

You can run web3 gear with the following command. Please make sure you run the Thor client first or you will get the ” unable to connect to Thor-Restful server” message.

web3-gear

By default, this will start web3-gear on 127.0.0.1:8545. To change the default behavior the following parameters are accepted:

• –host: rpc service host, eg: --host 127.0.0.1
• –port: rpc service port, eg: --port 8545
• –endpoint: thor restful service endpoint, eg: --endpoint http://127.0.0.1:8669
• –keystore: keystore file path, eg: --keystore /Users/(username)/keystore), default=thor stand-alone(solo) built-in accounts
• –pascode: passcode of keystore, eg: --passcode xxxxxxxx

Setup Remix or Truffle

Use Remix

Change the Remix environment to Web3 provide.

Use Truffle

• Truffle 4.0.6+ support

npm install -g truffle

Modify the configuration of truffle first(truffle.js):

module.exports = {
    networks: {
        development: {
            host: "localhost",
            port: 8545,
            network_id: "*" // Match any network id
        }
    }
};

Then you can use truffle’s command line tool.