Lightweight-Blockchain

A lightweight but complete blockchain.

Two version:

./src contains source files purely in Golang with BoltDB

./demo contains a simple demo written purely in Python 3.6 with Flask for Web server.

Golang version is more strict with all cryptography design and complete data structures, and use database with BoltDB.

Python version is more lightweight and just for demostration, without checking the validation of address in cryptography part, nor use a file system database. Python version directly use the HTTP APIs in the localhost (default port 5000).

Golang Version Environment and APIs

Require golang 10 or more.

Require BoltDB as database module, and ripemd160 algorithms library:

go get github.com/boltdb/bolt
go get golang.org/x/crypto/ripemd160

Build the code:

go build -o ./build/lightchain ./src

Set the node id NODE_ID:

export NODE_ID=3000

APIs Documentation

Create a blockchain and send genesis block reward to ADDRESS

./lightchain createblockchain -address ADDRESS

Generates a new key-pair and saves it into the wallet file

./lightchain createwallet

Get balance of ADDRESS

./lightchain getbalance -address ADDRESS

Lists all addresses from the wallet file

./lightchain listaddresses

Print all the blocks of the blockchain

./lightchain printchain

Rebuilds the UTXO set

./lightchain reindexutxo

Send AMOUNT of coins from FROM address to TO. Mine on the same node, when -mine is set

./lightchain send -from FROM -to TO -amount AMOUNT -mine

Start a node with ID specified in NODE_ID env. var. -miner enables mining

./lightchain startnode -miner ADDRESS

Demo (Python) Version Environment and HTTP APIs

The Python version is more simple, mainly focus on web server request, without establishing a full version of database.

Require Python 3.6 or more. Require Flask and requests modules.

pip install Flask==0.12.2 requests==2.18.4
pip install pipenv          # for multi-nodes testing 
pipenv --python=python3.6
pipenv install

Run single node (default port is 5000 in local host):

cd demo
Python3.6 blockchain.py

Run several nodes in virtual environment:

pipenv run python blockchain.py
pipenv run python blockchain.py -p 5001
pipenv run python blockchain.py -p 5002

APIs Document

To get full chain, send a GET request:

curl http://localhost:5000/chain

To publish a transaction with a POST request:

curl -X POST -H "Content-Type: application/json" \
    -d '{"sender": "1senderAdd", "recipient": "3recipientAdd", "amount": 4}' \
    "http://localhost:5000/transactions/new"

To mine a block, send a GET request:

curl http://localhost:5000/mine

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