README.md

The JavaScript implementation of the IPLD

The JavaScript implementation of the IPLD, InterPlanetary Linked-Data

Project Status

We've come a long way, but this project is still in Alpha, lots of development is happening, API might change, beware of the Dragons 🐉.

Want to get started? Check our examples folder. You can check the development status at the js-ipld Waffle Board.

Weekly Core Dev Calls

Tech Lead

Volker Mische

Lead Maintainer

Volker Mische

Table of Contents

• Install
• Usage
• API
  • IPLD constructor
    • options.blockService
    • options.formats
    • options.loadFormat(codec)
  • .put(nodes, format, options)
  • .resolve(cid, path)
  • .get(cids)
  • .remove(cids)
  • .tree(cid, [path], [options])
  • .addFormat(ipldFormatImplementation)
  • .removeFormat(codec)
  • Properties
    • defaultOptions
• Packages
• Contribute
• License

Install

> npm install --save ipld

Usage

const Ipld = require('ipld')
const IpfsRepo = require('ipfs-repo')
const IpfsBlockService = require('ipfs-block-service')

const initIpld = (ipfsRepoPath, callback) => {
  const repo = new IpfsRepo(ipfsRepoPath)
  repo.init({}, (err) => {
    if (err) {
      return callback(err)
    }
    repo.open((err) => {
      if (err) {
        return callback(err)
      }
      const blockService = new IpfsBlockService(repo)
      const ipld = new Ipld({blockService: blockService})
      return callback(null, ipld)
    })
  })
}

initIpld('/tmp/ifpsrepo', (err, ipld) => {
  // Do something with the `ipld`, e.g. `ipld.get(…)`
})

API

The IPLD API works strictly with CIDs and deserialized IPLD Nodes. Interacting with the binary data happens on lower levels. To access the binary data directly, use the Block API.

All methods that return an async iterator return one that got extended with convenience methods:

• iter.first(): Return the first item only
• iter.last(): Return the last item only
• iter.all(): Return all items as array

Example:

const result = ipld.get([cid1, cid2])
const node1 = await result.first()

IPLD constructor

Creates and returns an instance of IPLD.

const ipld = new Ipld(options)

The options is an object with any of these properties:

options.blockService

Type	Default
ipfs.BlockService instance	Required (no default)

Example:

const blockService = new IpfsBlockService(repo)
const ipld = new Ipld({blockService: blockService})

options.formats

Type	Default
Array of IPLD Format implementations	[require('ipld-dag-cbor'), require('ipld-dag-pb'), require('ipld-raw')]

By default only the dag-cbor), dag-pb) and raw) IPLD Formats are supported. Other formats need to be added manually. Here is an example if you want to have support for ipld-git only:

const ipldGit = require('ipld-git')

const ipld = new Ipld({
  formats: [ipldGit],
  …
})

options.loadFormat(codec)

Type	Default
async Function	null

Function to dynamically load an IPLD Format. It is passed a codec, the multicodec code of the IPLD format to load and returns an IPLD Format implementation. For example:

const multicodec = require('multicodec')
const ipld = new Ipld({
  async loadFormat (codec) {
    if (codec === multicodec.GIT_RAW) {
      return require('ipld-git')
    } else {
      throw new Error('unable to load format ' + multicodec.print[codec])
    }
  }
})

.put(nodes, format, options)

Stores the given IPLD Nodes of a recognized IPLD Format.

• nodes (Iterable<Object>): deserialized IPLD nodes that should be inserted.
• format (multicodec, required): the multicodec of the format that IPLD Node should be encoded in.
• options is applied to any of the nodes and is an object with the following properties:
  • hashAlg (multicodec, default: hash algorithm of the given multicodec): the hashing algorithm that is used to calculate the CID.
  • cidVersion (number, default: 1): the CID version to use.
  • onlyHash (boolean, default: false): if true the serialized form of the IPLD Node will not be passed to the underlying block store.

Returns an async iterator with the CIDs of the serialized IPLD Nodes.

.resolve(cid, path)

Retrieves IPLD Nodes along the path that is rooted at cid.

• cid (CID, required): the CID the resolving starts.
• path (IPLD Path, required): the path that should be resolved.

Returns an async iterator of all the IPLD Nodes that were traversed during the path resolving. Every element is an object with these fields:

• remainderPath (string): the part of the path that wasn’t resolved yet.
• value (*): the value where the resolved path points to. If further traversing is possible, then the value is a CID object linking to another IPLD Node. If it was possible to fully resolve the path, value is the value the path points to. So if you need the CID of the IPLD Node you’re currently at, just take the value of the previously returned IPLD Node.

.get(cids)

Retrieve several IPLD Nodes at once.

• cids (Iterable<CID>): the CIDs of the IPLD Nodes that should be retrieved.

Returns an async iterator with the IPLD Nodes that correspond to the given cids.

Throws an error if a IPLD Node can’t be retrieved.

.remove(cids)

Remove IPLD Nodes by the given cids

• cids (Iterable<CID>): the CIDs of the IPLD Nodes that should be removed.

Throws an error if any of the Blocks can’t be removed. This operation is not atomic, some Blocks might have already been removed.

.tree(cid, [path], [options])

Returns all the paths that can be resolved into.

• cid (CID, required): the CID to get the paths from.
• path (IPLD Path, default: ''): the path to start to retrieve the other paths from.
• options:
  • recursive (bool, default: false): whether to get the paths recursively or not. false resolves only the paths of the given CID.

Returns an async iterator of all the paths (as Strings) you could resolve into.

.addFormat(ipldFormatImplementation)

Add support for an IPLD Format

• ipldFormatImplementation (IPLD Format, required): the implementation of an IPLD Format.

Returns the IPLD instance. This way you can chain addFormat() calls.

.removeFormat(codec)

Remove support for an IPLD Format

• codec (multicodec, required): the codec of the IPLD Format to remove.

Returns the IPLD instance. This way you can chain removeFormat() calls.

Properties

defaultOptions

Default options for IPLD.

Packages

Listing of dependencies from the IPLD ecosystem.

This table is generated using the module package-table with package-table --data=package-list.json.

Package	Version	Deps	CI	Coverage	Lead Maintainer
IPLD Formats
ipld-bitcoin					Volker Mische
ipld-dag-cbor					Volker Mische
ipld-dag-pb					Volker Mische
ipld-ethereum					kumavis
ipld-git					Volker Mische
ipld-raw					Volker Mische
ipld-zcash					Volker Mische
Data Types (non IPLD specific)
multihashes					David Dias
ipfs-block					Volker Mische
Storage
ipfs-repo					Jacob Heun
interface-datastore			N/A		Pedro Teixeira
ipfs-block-service					Volker Mische

Contribute

Feel free to join in. All welcome. Open an issue!

This repository falls under the IPFS Code of Conduct.

License

MIT