minqiz / dotcoin-minicoin

Dotcoin

In this assignment, you will build a small ledger-based blockchain similar to Bitcoin. The original Bitcoin whitepaper is an excellent resource however the tutorial Naivecoin: a tutorial for building a cryptocurrency provides a simpler but yet comprehensive overview of the most important Bitcoin concepts.

You are tasked to implement a Python version of Naivecoin called Dotcoin. The goal is not solely to translate this code into python but rather understand in details the Bitcoin mechanics. You code must work but your grade will also depend on your understanding of the concepts. You will likely be asked to explain your code during during a live meeting with the instructor.

The blockchain will run within a Docker container and use Python Flask for the HTTP server (instead of Node Express in the tutorial) and the Python Libsodium Library (PyNaCl) for the cryptography primitives.

Build the docker image (first time only)

docker build -t dotcoin .

To run your code in debug mode (the server will automatically reload when the source files change)

docker run --rm -p 5000:5000 -v $(pwd)/flask-server:/shared dotcoin flask --app dotcoin.py --debug run --host=0.0.0.0

Type ctrl-c to stop the server.

How to Run

Step 1 - Build React app

cd react-app && npm run build

Step 2 - Create docker network

docker network create -d bridge my-bridge-network

Step 3 - Run multiple nodes

docker run --rm --network=my-bridge-network -p {{ PORT_NUM }}:5000 -e PORT={{ PORT_NUM }} -v $(pwd)/flask-server:/shared dotcoin flask --app dotcoin.py --debug run --host=0.0.0.0

Replace {{ PORT_NUM }} with port number that you want to run the node on. For example, to run on port 5001:

docker run --rm --network=my-bridge-network -p 5001:5000 -e PORT=5001 -v $(pwd)/flask-server:/shared dotcoin flask --app dotcoin.py --debug run --host=0.0.0.0

Step 4 - Open http://localhost:5000 in the browser to see the UI.

API

Get blockchain

• description: retrieve all blocks in blockchain
• request: GET /blocks

$ curl http://localhost:5000/blocks

Find block by hash

• request: GET /block/:hash

$ curl http://localhost:5000/block/816534932c2b7154836da6afc367695e6337db8a921823784c14378abed4f7d7

Find transaction by id

• request: GET /transaction/:id

$ curl http://localhost:5000/transaction/b4cd43dcf8ae6f51316d388ded308ff99ead8c2e1fc1e2e1247475e058b6b1d7

Get transaction pool

• request: GET /transactionPool

$ curl http://localhost:5000/transactionPool

Get all UTXOs

• request: GET /unspentTransactionOutputs

$ curl http://localhost:5000/unspentTransactionOutputs

Get my UTXOs

• request: GET /myUnspentTransactionOutputs

$ curl http://localhost:5000/myUnspentTransactionOutputs

Get address (public key)

• request: GET /address

$ curl http://localhost:5000/address

Get UTXOs by address

• description: return a list of UTXOs of a given address
• request: GET /address/:address

$ curl http://localhost:5000/address/4e64c77bac3408cd916d0ce4fea383df2c56954e22e88d2859dca5e2e4187d49

Mine block

• description: this API is for testing purpose only, it's not used by frontend. The actual mine block task is running continuously in the background.
• request: POST /mineBlock

$ curl -X POST http://localhost:5000/mineBlock

Get balance

• request: GET /balance

$ curl http://localhost:5000/address

Send transaction

• description: create a transaction and broadcast it to its connected peers
• request: POST /sendTransaction
• body: object
  • address: (string) public key of receiver
  • amount: (number) amount to send

$ curl -X POST -H "Content-Type: application/json" -d '{"address": "c3797bc67dff6f53efa0c4d166f5c29eb33ebf09f8b9c21af1a84ef7d537a9cd", "amount": 10}' http://localhost:5000/sendTransaction

Generate key pair

• description: generate a key pair and return public key
• request: GET /getKeyPair

$ curl http://localhost:5000/getKeyPair

Get peers

• description: return a list of urls of connected peers
• request: GET /peers

$ curl http://localhost:5000/peers

Join network

• description: join the network by sending the request to the url you want to connect to, will receive a blockchain as response
• request: POST /joinNetwork
  • body: object
    • url: (string) url of node you want to connect

$ curl -X POST -H "Content-Type: application/json" -d '{"url": "http://172.18.0.3:5000"}' http://localhost:5000/joinNetwork

• The url can be found by running the following command (get ip of containers):

docker network inspect my-bridge-network