Deploying a NEP-5 smart contract (part 1)

If you’ve haven’t set up a privet net already, please do so by taking a look at my previous articles, 1 2 & 3.

Before we begin, we need to cover the topic of smart contracts; what is it? A smart contract is a set of functional code (not object-oriented!), written to the blockchain via transaction and callable by wallets thereafter. A major advantage of NEO is that it supports many of today’s most well known languages such as C#, Python, Java … Our articles focus on the use of Python.

What is NEP-5? Similar to ERC20 for Ethereum, NEP-5 is a currency standard, recommending that you implement a couple of predefined functions (name, symbol, balanceOf, transfer … ). As with any standardization system, this allows digital wallets to focus on its demographic preferences without worrying about the token, while you [o lovely smart contract developer] does not need to worry about the user experience!

Lastly we cannot talk about deployment without talking about the compiler! We will need a compiler because NEO nodes do not understand Python or Java or C# or any other high level language. Instead, it understands byte code and it is the job of the compiler to translate it for us! Our compiler of choice will be Neo-boa: taking our NEP-5 compliant python smart contract, and turn it into byte-code or machine readable code.

Workflow summary: code → compile → deploy! let’s start!

Step 1: create your wallet

Open up the neo-prompt in Ubuntu, source venv/bin/activate , np-prompt -p <server ip> . Then:

create wallet testWallet1

enter a 10 character (minimum) password

Step 2: gathering funds

Your new wallet has no GAS in it (obviously) … but you need some to deploy contracts. Luckily, the network already has an importable WIF/private key with money inside.

import wif KxDgvEKzgSBPPfuVfw67oPQBSjidEiqTHURKSDL1R7yGaGYAeYnrwallet rebuild

*the WIF may change at any time, refer to the documentation here

Step 3: pulling the an NEP-5 standard template from the internet

I will assume you already have git installed on your local. Open up a new command prompt:

:you may want to use the same base path as your neo-python installcd <storage location>git clone https://github.com/neonexchange/neo-ico-template

Step 4: installing Neo-boa (compiler)

:you may want to use the same base path as your neo-python installcd <storage location>git clone https://github.com/CityOfZion/neo-boa.git

cd neo-boa/python3.6 -m venv venvsource venv/bin/activate

pip install -r requirements.txt

Step 5: editing the smart contract code: getting the wallet hash

Go to your np-prompt console, and type wallet , you will see the following:

example testnet wallet

Copy the script hash at the top, mine is b’\xc6\x04\x1c\x97\x15\xc1\xe4\x87/\xe5\xbf\xd4\t\xf5\xe1\sbd_>\scd\xf8'

Using your favorite editor, open up <smartcontract>/nex/token.py . replace the TOKEN_OWNER with your own wallet hash.

Rename TOKEN_NAME and TOKEN_SYMBOL to anything you want!

Now you are ready to compile and deploy your personalized NEP5 smart contract!

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Next week’s guide: Deploying a NEP-5 smart contract (part 2)

Quick thanks to thomas saunders and the NEX team for providing such an awesome smart contract template to explore!