Band Protocol Python Library

Official Python Client for Band Chain

Band Protocol Python Library is written in Python 3, and combined with Band Chain ABI, the client provides a robust, easy-to-use, and future-proof way to interact with Band Chain.

Install

$> git clone https://github.com/bandprotocol/python-client.git
$> cd python-client
$> python3 -m venv
$> source venv/bin/activate
$> pip install -r requirements.txt

Basic Usage

$> source venv/bin/activate
$> python

>>> from pyband import BandProtocolClient
>>> from pyband.config import Config, RealClock
>>> from pyband.abi import abi
>>> clock = RealClock()
>>> secret_key = 'e480f19604b0e44a0b65b67315c97ffac223a4e85c764a6890ac05e3047fb93878e3d3647baadde0b9e92c3bb2eca1b8b8944cf263c5ef38a7d489f8a64baedd'
>>> client = BandProtocolClient(Config('http://localhost:26657/', clock), abi, secret_key)

Contract

Every thing on chain is contracts, so every transaction need to know address of contract to send transaction. This library provides contract view to call function to create and send transaction to chain including generate signature of transaction by your provided secret_key.

Contract view can declare like this

>>> view = client.blockchain.<Contract type>(<Address of contract>)

Replace < and

with type of contract eg. Creator, Account. and hex address string.

Almost transaction need to send keymanager of sender used in sign message and nonce to garuntee not duplicate transaction.

Creator

Contract to create other contract has only 1 function create. If contract creating success, it will return address of new contract.

>>> creator = client.blockchain.Creator('0' * 40)
>>> addr = creator.create(client.blockchain.Account.constructor(client.key.get_vk())) 
>>> account = client.blockchain.Account(addr)

Every contract (except Creator) have constructor function to create raw_tx to create contract in chain. Input parameter for each contract define at abi file (constructor_params) for each contract.

Account

View of account contract

Token

View of token contract have function to manage token eg. transfaer, buy, sell token.

>>> ct_id = creator.create(client.blockchain.Token.constructor('bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb', bytes.fromhex('06080702')))
>>> ct_token = client.blockchain.Token(ct_id)

>>> token.mint(client.key,0,1000)
>>> ct_token.buy(client.key,1, 10)

>>> token.balance(addr)
900
>>> ct_token.balance(addr)
10

Voting

View of voting contract have function to request vote power, commit vote, reveal vote etc.

voting_id = creator.create(client.blockchain.Voting.constructor(ct_id))
vote = client.blockchain.Voting(voting_id)
# request vote (send token to contract and get voting power)
vote.request_voting_power(voter1.key, 2, 700)
# commint vote
vote.commit_vote(voter1.key, 3, 2, hashlib.sha256(b'\x00' + varint_encode(79)).digest(), 700)
# reveal vote
vote.reveal_vote(voter1.key, 4, 2, False, 79)

Registry

View of Registry contract have function to apply application, challenge application, reward claim for winning voter, etc. Specification of TCR can read at https://github.com/bandprotocol/bandchain

tcr_id = creator.create(client.blockchain.Registry.constructor(ct_id, voting_id, 50, 50, 100, 100, 100, 100))
tcr = client.blockchain.Registry(tcr_id)
tcr.apply(client.key, 1, "Submit first news.", 120)
tcr.challenge(client2.key, 3, 1, "That is a fake news.")

ABI

Interface of every transaction that you can send to chain store in pyband/abi.py file

Example Code

pyband/test_client1.py you can copy code from this file and paste on terminal. If you want to run a file. python test_client1.py please change file location to top level of pyband or edit import in file to match what script file location.