Is there an easy way to iterate forward starting from the genesis block?
Sean Shubin
Just started looking at bitcoinj. I am familiar with the bitcoin data structure, and want to write applications that analyze the blockchain data, so I am looking for a library that lets me interact with the bitcoin protocol directly. Does bitcoinj have that capability or is it only a higher level library for managing wallets? For my first prototype I intend to load the first 5000 blocks and compute for myself how many satoshi’s are at each address. I have already found the getGenesisBlock method on the NetworkParameters class, but am having trouble finding out how to get the next block without creating a WalletAppKit and loading the previous 2,104,841 blocks off the test net from the BlockStore. That seems like the wrong direction. I am hoping someone already familiar with bitcoinj can point me in the right direction regarding which classes I should be looking at first, without all the noise of capabilities I don’t need at the moment.
Andreas Schildbach
directly, without any wallet.
Classes to look at are Peer and PeerGroup, and the entire Message hierarchy.
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Sean Shubin
val fullStoreDepth = 10 // let's just start with the first 10 blocks
val blockStore = MemoryFullPrunedBlockStore(networkParameters, fullStoreDepth)
val chain = FullPrunedBlockChain(networkParameters, blockStore)
val peerGroup = PeerGroup(networkParameters, chain)
val dnsDiscovery = DnsDiscovery(networkParameters)
peerGroup.addPeerDiscovery(dnsDiscovery); // I expected this to add the peers automatically, must be missing something
peerGroup.start()
peerGroup.downloadBlockChain() // looks like this just waits for a peer to show up
println(blockStore.chainHeadHeight)
println(peerGroup.connectedPeers.size)
Sean Shubin
val blockStore = MemoryBlockStore(networkParameters)
val chain = BlockChain(networkParameters, blockStore)
val peerGroup = PeerGroup(networkParameters, chain)
var blockOrder = 0
var done =false
fun displayBlock(block:Block){
println("[$blockOrder] ${block.hash}")
}
peerGroup.addBlocksDownloadedEventListener {
peer, block, filteredBlock, blocksLeft ->
if(!done) {
blockOrder++
displayBlock(block)
if(blockOrder >= blockLimit-1) done = true
if(blocksLeft == 0) done = true
}
}
val dnsDiscovery = DnsDiscovery(networkParameters)
peerGroup.addPeerDiscovery(dnsDiscovery);
val peer = peerGroup.waitForPeers(1).get()[0]
displayBlock(networkParameters.genesisBlock)
peer.startBlockChainDownload()
while(!done){
Thread.sleep(1)
}