Why Yet Another Blockchain Explorer?

There are many already out there. I wrote this blockchain explorer to learn Elixir, Phoenix, and Blockchain.

I couldn't have done it without github.com/pcorey/hello_blockchain

It can be seen running at http://subcryption.com/

23 March 2020 - tested with Elixir 1.10, Erlang/OTP 22 and bitcoind version v0.19.99.0-97b068750

You need to be running bitcoind:

start-bitcoind.sh regtest (twice)

start-bitcoind.sh testnet

or

start-bitcoind.sh mainnet

(The last of these runs a full node, and uses a lot of disk space - 200 Gb and counting)

If you are using regtest, the most economical choice, wait a few seconds, then run

regenerate.sh

to generate some blocks

For what regtest, testnet and mainnet mean, see https://dzone.com/articles/bitcoin-and-junit

You need to change 'rpcuser' and 'rpcpass' in config/config.exs to whatever you give as username/password arguments to the scripts

regtest mode

To do anything useful in regtest mode, you need at least two instances of bitcoind running

Create a .bitcoin/ folder in your home directory

Start the first instance like this

start-bitcoind.sh regtest USERNAME PASSWORD 1

and the second like this

start-bitcoind.sh regtest USERNAME PASSWORD 2

further information

See https://github.com/bitcoin/bitcoin

See ubuntu-install.txt for installation on Linux

To start Phoenix:

• Install dependencies with mix deps.get
• Install Node.js dependencies with cd assets then
• npm install
• ./node_modules/brunch/bin/brunch build
• cd ..
• Start Phoenix with mix phx.server

Wait a few minutes, then visit localhost:4000 in a browser

On a Mac, your data is written in ~/Library/Application Support/Bitcoin, unless you've specified a datadir (see start-bitcoind.sh). On Linux, ~/.bitcoin.

You can turn it into a soft link pointing to a large (500 Gb+) external drive - which you probably will have to do if using testnet or mainnet, as the blockchain just keeps getting bigger.

production

To run this app in production mode, look at start-phoenix-in-background.sh

You need to enter a 'secret key base' and a mysql username and password in config/prod.exs.

You should also add this line to the end of prod.exs. This overrides the RPC username and password in config.exs. Replace RPC_USERNAME and RPC_PASSWORD with the username and password with which you started bitcoind. They should not be the same as in config.exs, and they should not be RPC_USERNAME and RPC_PASSWORD!

config :blockchain_explorer, bitcoin_url: "http://RPC_USERNAME:RPC_PASSWORD@127.0.0.1:16591"

Do not check this file into Git after you've changed it - do git reset --hard to undo your changes to prod.exs.

mix phx.gen.secret will generate a new 'secret key base'.