G Coin
A simple implementation of Blockchain for understanding easily.
It includes only basic concepts.
- Block and Hash
- Transaction and Balance
- Mining with Proof of Work
- Chain validation and consensus conflicts
Articles (Korean)
- 골빈해커님의 g-coin 분석 1부
- 골빈해커님의 g-coin 분석 2부
- 골빈해커님의 g-coin 분석 3부 (Comming soon)
Modules
bold is core function.
- blockchain : chain structure /w blocks
- new_block: make block /w hash of previous block and current proof
- valid: validate chain rules of all chain
- block : block structure
- hash: hash itself
- proof : proof of work
- find_proof
- valid_proof
- miner : Mining new block and get rewards
- transaction : data object
- book : book of transactions
- check_balance /w transaction history of sender account
- node
- consensus_with_neighbor
Endpoints
/transaction: Add a transaction and get pending transactions./mine: Mining. Find proof and make block with rewards./node: Add a node as a neighbor node/chain: Get full chain to validate./chain/valid: Valid chain/chain/consensus: Consensus conflicts
Basic Flow
/transaction: Add trasaction for sending coin.- Check balance and add to blockchain
- Use '0' as a sender id at the first time. It's the genesis wallet.
/mine: Mining for making block.- Find proof with previous proof
- Add a reward to transactions
- Make a new block with proof and hash of previous block
- Add the block to chain of blocks
- Clear current transactions
/chain/consensus: Consensus conflicts with neighbor nodes.- Fetch blockchain from all neighbor nodes.
- Check which has the longest chain and valiates it's chain.
- Add neighbor nodes before do this using
/node
Try using Insomnia
- Download Insomnia
- Import from insomnia.json
Mining practice
python app.py --port 5000- First try
- POST
/transaction- /w {sender: '0', recipient: 'golbin', amount: 10}
- GET
/transaction - GET
/chain - POST
/mine - GET
/chain - GET
/transaction
- POST
- Second try
- POST
/transaction- /w {sender: 'golbin', recipient: 'bluecat', amount: 10}
- POST
/transaction- /w {sender: 'golbin', recipient: 'bluecat', amount: 10}
- POST
/mine - GET
/chain
- POST
Consensus practice
python app.py --port 5000
python app.py --port 5001- POST
/node- to 127.0.0.1:5000 /w {address: '127.0.0.1:5001'}
- POST
/node- to 127.0.0.1: 5001 /w {address: '127.0.0.1:5000'}
- Try several mining
- GET
/chain/valid - POST
/chain/consensus
Requirements
- Python >= 3.6
- Flask >= 0.12
- Requests >= 2.18