bcrpc

Tiny Bitcoin RPC wrapper for Node.js.

Usage

Each rpc function is exposed as a function in an instantiated RpcAgent. The first arguments are parsed as array of arguments, as expected by that specific rpc function, see Bitcoin Core RPC Docs. The last argument is an optional callback function, if no callback is provided, it will return a promise.

The following program can be saved and and run in the same directory as the index.js file from bcrpc. It will print out the latest block number along with its hash. Change username and password to those from the bitcoin.conf file and also change the port number to 18332 if you are running Bitcoin on testnet.

const RpcAgent = require('./index'); // Change './index' to 'bcrpc' if running outside of bcrpc directory
agent = new RpcAgent({port: 18332, user: 'username', pass: 'password'});

// Using Callbacks
agent.getBlockCount(function (err, blockCount) {
  if (err)
    throw Error(JSON.stringify(err));
  console.log(blockCount.result);
  agent.getBlockHash(blockCount.result, function (err, hash) {
    if (err)
      throw Error(JSON.stringify(err));
    console.log(hash.result);
  })
});

// Using Promises
agent.getBlockCount()
.then((blockCount) => {
  console.log(blockCount);
  return agent.getBlockHash(blockCount);
})
.then((hash) => {
  console.log(hash);
})
.catch((err) => {
  console.error(err);
  return err;
});

Example

Make sure a Bitcoin Core node is running on your system already. This example creates a new project and shows bcrpc being used.

$ mkdir myproject
$ cd myproject
$ npm init
  [continue with default options]
$ npm install bcrpc

Create a new file called server.js and write the following in it (change username and password to those from the bitcoin.conf file, also change the port number to 18332 if you are running Bitcoin on testnet):

const RpcAgent = require('bcrpc');
agent = new RpcAgent({port: 18332, user: 'username', pass: 'password'});

agent.getBlockCount(function (err, blockCount) {
  if (err)
    throw Error(JSON.stringify(err));
  console.log(blockCount.result);
  agent.getBlockHash(blockCount.result, function (err, hash) {
    if (err)
      throw Error(JSON.stringify(err));
    console.log(hash.result);
  })
});

Then run $ npm start. You should get the latest block number along with its hash printed out:

> [email protected] start /home/user/myproject
> node server.js

1768837
00000000000009f6c6eba1dde1cf61022ea59d58f31b2e447c25297c29601008

Testing

Install mocha first with $ sudo npm install mocha -g. Change username and password to those from the bitcoin.conf file.

$ git clone https://github.com/dgarage/bcrpc.git
$ cd bcrpc
$ npm install
$ export BITCOIND_USER=username
$ export BITCOIND_PASS=password
$ export BITCOIND_PORT=18332
$ npm test

If everything is configured properly you should see this output:

> [email protected] test /home/user/bcrpc
> mocha tests.js



  BitcoinD
    ✓ is running

  bcrpc
    ✓ can get info


  2 passing (37ms)