Simple Bitcoin-like blockchain for educational purpose

With dummy-blockchain you can get a feel on how the peer-to-peer Bitcoin protocol works by launching and interacting with multiple independent nodes.

A node can do the following:

• include a new transaction to its pending pool of transactions
• include its pending transactions to a new block by "mining" a new block that will be appended to the node's chain
• add a node to its list of known nodes
• check if a node from its list of know nodes has a longer chain and, if that's the case, replace its current chain by the longest one found
• check the validity of its chain

A node offers a user-friendly http interface and a REST api. Once the node is started, the http interface can be accessed at localhost:8080. This is also the root url for the REST api calls.

All the data are kept in-memory and destroyed once the node is shut down.

blockchain/ <- the interesting stuff
docs/       <- some screenshots
gui/        <- the http frontend and REST handlers
mod.go      <- the http server setup and entrypoint

Each node is an http server. You can run as many as you want. The arguments are optional.

You can either build and run a node from source, or use one of the realease, which are available for Linux, Mac, and Windows (check the release section of the repo).

Build and run from source:

# Build and run a node on http://localhost:8081
go run mod.go -listen-addr :8081 -owner Alice

Run from the release:

# Run a node on a Mac, using http://localhost:8081
./dummyblockchain.darwin-amd64 -listen-addr :8081 -owner Alice

The owner indicates who the transaction fees earned by the node will be sent to.

Get the chain

GET /get_chain

Mine a block

GET /mine_block

Check and replace chain if needed

GET /replace_chain

Check the chain validity

GET /is_valid

Add a node

POST /add_node

# body application/json 
{
    "Nodes": [
        {
            "Host": "127.0.0.1",
            "Port": 8081
        },
        ...
    ]
}

Add a transaction

POST /add_transaction

# Body application/json
{
    "Sender": "Alice",
    "Receiver": "Bob",
    "Amount": 10
}

This code is adapted from the Blockchain A-Z™: Learn How To Build Your First Blockchain online course.