SYNOPSIS

or #icjs on freenode

A module to store and interact with blocks.

INSTALL

npm install icjs-blockchain

API

icjs-blockchain

A module to store and interact with blocks

• Blockchain
  • new Blockchain(opts)
  • BlockChain Properties
  • BlockChain methods
    • blockchain.putBlock(block, [callback])
    • blockchain.getBlock(hash, [callback])
    • blockchain.getBlockInfo(hash, cb)
    • blockchain.getBlockHashes(parentHash, count, cb)
    • blockchain.getBlockChain(startingHashes, count, cb)
    • blockchain.selectNeededHashes(hashes, cb)

Blockchain

Implements functions for retrieving, manipulating and storing HappyUC's blockchain

new Blockchain(opts)

Creates new Blockchain object

• opts.blockDB - the database where Blocks are stored and retreived by hash. Should be a levelup instance.
• opts.detailsDB - the database where Block number resolutions and other metadata is stored. Should be a levelup instance.
• opts.validate - this the flag to validate blocks (e.g. Proof-of-Work).

BlockChain Properties

• head - The Head, the block that has the most weight
• parentHead- The parent of the head block
• genesisHash - The hash of the genesis block
• height - The height of the blockchain
• totallDifficulty - The totall difficulty which is the some of a the difficulty of all the prevous blocks

BlockChain methods

blockchain.putBlock(block, callback)

Adds a block to the blockchain.

• block - the block to be added to the blockchain
• callback - the callback. It is given two parameters err and the saved block

blockchain.getBlock(blockTag, callback)

Gets a block by its blockTag.

• blockTag - the block's hash or number
• callback - the callback. It is given two parameters err and the found block (an instance of https://github.com/icjs/icjs-block) if any.

blockchain.getDetails(hash, callback)

Retrieves meta infromation about the block and passed it to the callback

• hash - the hash of the block as a Buffer or a hex String
• callback - the callback which is passed an Object containing the following properties:
• • parent - the hash of the parent block
• • td - the total difficulty of the block
• • number - the block number
• • child - the block's children
• • genesis - boolean (true if genesis block, false if not)
• • inChain - TODO
• • staleChildren - TODO

blockchain.getBlockHashes(parentHash, count, callback)

Gets a segment of the blockchain starting at the parent hash and contuning for count blocks returning an array of block hashes orders from oldest to youngest.

• parentHash - the block to start from. Given as a Buffer or a hex String
• count - a Number specifing how many block hashes to return
• callback - the callback which is give an array of block hashes

blockchain.getBlockChain(startingHashes, count, callback)

gets a section of the blockchain in a form of an array starting at the parent hash, up count blocks

• startingHashes - an array of hashes or a single hash to start returning the chain from. The first hash in the array that is found in the blockchain will be used.
• count - the max number of blocks to return
• callback - the callback. It is given two parameters err and blockchain. err is any errors. If none of the starting hashes were found err will be notFound. blockchain is an array of blocks.

blockchain.selectNeededHashes(hashes, callback)

Given an ordered array, returns to the callback an array of hashes that are not in the blockchain yet.

• hashes - an Array hashes
• callback - the callback