IPFS Blocks JavaScript Implementation
IPFS implementation of the BlockService and Block data structure in JavaScript.
Description
Block - A block is a blob of binary data.
BlockService - A BlockService is a content-addressable store for blocks, providing an API for adding, deleting, and retrieving blocks. A BlockService is backed by an IPFS Repo as its datastore for blocks, and uses an IPFS Exchange implementation to fetch blocks from the network.
┌────────────────────┐│ BlockService │└────────────────────┘ │ ┌─────┴─────┐ ▼ ▼┌─────────┐ ┌────────┐│IPFS Repo│ │Exchange│└─────────┘ └────────┘
Example
const blocks = const IPFSRepo = // storage repoconst memstore = // in-memory store // setup a repovar repo = 'example' stores: memstore // create a blockconst block = 'hello warld'consoleconsole // create a serviceconst bs = repo // add the block, then retrieve itbs
outputs
<Buffer 68 65 6c 6c 6f 20 77 61 72 6c 64>
<Buffer 12 20 db 3c 15 23 3f f3 84 8f 42 fe 3b 74 78 90 90 5a 80 7e a6 ef 2b 6d 2f 3c 8b 2c b7 ae be 86 3c 4d>
true
Installation
npm
> npm i ipfs-blocks
Setup
Node.js
const blocks =
Browser: Browserify, Webpack, other bundlers
The code published to npm that gets loaded on require is in fact a ES5 transpiled version with the right shims added. This means that you can require it and use with your favourite bundler without having to adjust asset management process.
var blocks = require('ipfs-blocks')
<script>
Tag
Browser: Loading this module through a script tag will make the Unixfs
obj available in
the global namespace.
<!-- OR -->
API
const blocks =
Block
var block = new blocks.Block(data)
Creates a new block with raw data data
.
block.data
The raw data of the block. Its format matches whatever was provided in its constructor.
block.key
The multihash of the block's data, as a buffer.
var bs = new blocks.BlockService(repo[, exchange])
Creates a new block service backed by IPFS Repo repo
for storage, and
IPFS Exchange for retrieving blocks from the network. Providing an
exchange
is optional.
bs.addBlock(block, callback(err))
Asynchronously adds a block instance to the underlying repo.
bs.addBlocks(blocks, callback(err))
Asynchronously adds an array of block instances to the underlying repo.
Does not guarantee atomicity.
bs.getBlock(multihash, callback(err, block))
Asynchronously returns the block whose content multihash matches multihash
.
Returns an error (err.code === 'ENOENT'
) if the block does not exist.
If the block could not be found, expect err.code
to be 'ENOENT'
.
bs.getBlocks(multihashes, callback(err, blocks))
Asynchronously returns the blocks whose content multihashes match the array
multihashes
.
blocks
is an object that maps each multihash
to an object of the form
err: Error block: Block
Expect blocks[multihash].err.code === 'ENOENT'
and blocks[multihash].block === null
if a block did not exist.
Does not guarantee atomicity.
bs.deleteBlock(multihash, callback(err))
Asynchronously deletes the block from the store with content multihash matching
multihash
, if it exists.
bs.deleteBlocks(multihashes, callback(err))
Asynchronously deletes all blocks from the store with content multihashes matching
from the array multihashes
.
Does not guarantee atomicity.
License
MIT