Using bitcore-p2p to query specific block information

orweinberger · January 29, 2015, 2:31pm

Hi,

I’ve started using bitcore-p2p which works great. I’m working on a project that needs to validate remote full nodes, for that project I was wondering if I could use bitcore-p2p to query a certain full node for a specific block height/hash and get the details for that block.

Is that possible? I looked through the tests and could not find anything similar.

Thanks,

maraoz · January 29, 2015, 3:24pm

Hey Or,
Yes you can. There’s no example yet, but I’m working on it. I’ll link you to it when it’s ready.

For your information, you need to send a getdata message to the node, with the block hash.

orweinberger · January 29, 2015, 3:29pm

Thanks for replying so quickly @maraoz. I’ll try and play around with it, looking forward for the example.

maraoz · January 30, 2015, 8:19pm

@orweinberger: look at this work in progress:

github.com

maraoz/bitcore-p2p/blob/98990dbc82b3b7db4b698094f5c6e0621b7266ce/test/integration/bitcoind.js#L127


    }];
    peer.once('getdata', function(message) {
      message.inventory.should.deep.equal(inv);
      cb();
    });
    var message = new Messages.Inventory(inv);
    message.inventory[0].hash.length.should.equal(32);
    peer.sendMessage(message);
  });
});
it('can request block data', function(cb) {
  connect(function(peer) {
    peer.on('block', function(message) {
      (message.block instanceof Block).should.equal(true);
      cb();
    });
    // TODO: replace this for a new Messages.GetData.forTransaction(hash)
    var message = new Messages.GetData([{
      type: Messages.Inventory.TYPE.BLOCK,
      hash: BufferUtil.reverse(new Buffer(blockHash[network.name], 'hex'))
    }]);

I couldn’t make it work with very old blocks (bitcoind doesn’t respond the getdata message for those). Maybe the block has to be in the mempool to be returned.
If you find any clues, please report!