Skip to content

ethersphere/mantaray-js

Repository files navigation

Description

With this package you can manipulate and interpret mantaray data via MantarayNode and MantarayFork abstractions.

Exported Functions and Classes

You can import the followings directly from mantaray-js:

  • MantarayNode # class abstracting and manipulating Mantaray Node data
  • MantarayFork # class abstracting and manipulating Mantaray Fork data
  • checkForSeparator # checks for separator character in the node and its descendants prefixes
  • initManifestNode # initialize a manifest node
  • loadAllNodes # loads all mantaray nodes recursively from the storage
  • equalNodes # checks whether the two given Mantaray Nodes objects are equal in the in-memory abstraction level
  • Utils # all used utility functions in the library. Mostly operating on Uint8Array objects.
  • types* # not callable, referring all types exported and reachable from the index

Basic usage

Construct Mantaray

import { initManifestNode, Utils } from 'mantaray-js'

const node = initManifestNode()
const address1 = Utils.gen32Bytes() // instead of `gen32Bytes` some 32 bytes identifier that later could be retrieved from the storage
const address2 = Utils.gen32Bytes()
const address3 = Utils.gen32Bytes()
const address4 = Utils.gen32Bytes()
const address5 = Utils.gen32Bytes()
const path1 = new TextEncoder().encode('path1/valami/elso')
const path2 = new TextEncoder().encode('path1/valami/masodik')
const path3 = new TextEncoder().encode('path1/valami/masodik.ext')
const path4 = new TextEncoder().encode('path1/valami')
const path5 = new TextEncoder().encode('path2')
node.addFork(path1, address1)
node.addFork(path2, address2, { vmi: 'elso' }) // here 'vmi' is a key of metadata and 'elso' is its value
node.addFork(path3, address3)
node.addFork(path4, address4, { vmi: 'negy' })
node.addFork(path5, address5)
node.removePath(path3)
// (...)

Mantaray Storage Operations

import { MantarayNode } from 'mantaray-js'

const node = new MantarayNode()
// here `reference` parameter is a `Reference` type which can be a 32 or 64 bytes Uint8Array
// and `loadFunction` is a [loadFunction: async (address: Reference): Promise<Uint8Array>] typed function
// that returns the serialised raw data of a MantarayNode of the given reference
await node.load(loadFunction, reference)

// Manipulate `node` object then save it again
// (...)

// save into the storage with a storage handler [saveFuncion: async (data: Uint8Array): Promise<Reference>]
const reference = await node.save(saveFunction)

node binary format

The following describes the format of a node binary format.

┌────────────────────────────────┐
│    obfuscationKey <32 byte>    │
├────────────────────────────────┤
│ hash("mantaray:0.1") <31 byte> │
├────────────────────────────────┤
│     refBytesSize <1 byte>      │
├────────────────────────────────┤
│       entry <32/64 byte>       │
├────────────────────────────────┤
│   forksIndexBytes <32 byte>    │
├────────────────────────────────┤
│ ┌────────────────────────────┐ │
│ │           Fork 1           │ │
│ ├────────────────────────────┤ │
│ │            ...             │ │
│ ├────────────────────────────┤ │
│ │           Fork N           │ │
│ └────────────────────────────┘ │
└────────────────────────────────┘

Fork

┌───────────────────┬───────────────────────┬──────────────────┐
│ nodeType <1 byte> │ prefixLength <1 byte> │ prefix <30 byte> │
├───────────────────┴───────────────────────┴──────────────────┤
│                    reference <32/64 bytes>                   │
│                                                              │
└──────────────────────────────────────────────────────────────┘

Fork with metadata

┌───────────────────┬───────────────────────┬──────────────────┐
│ nodeType <1 byte> │ prefixLength <1 byte> │ prefix <30 byte> │
├───────────────────┴───────────────────────┴──────────────────┤
│                    reference <32/64 bytes>                   │
│                                                              │
├─────────────────────────────┬────────────────────────────────┤
│ metadataBytesSize <2 bytes> │     metadataBytes <varlen>     │
├─────────────────────────────┘                                │
│                                                              │
└──────────────────────────────────────────────────────────────┘

Testing

The testing needs running Bee client node for integration testing. You can set BEE_POSTAGE environment variable with a valid Postage batch or the test will create one for you.

The default value of the Bee Debug API endpoint is http://localhost:1635. If your address diverges from that, please, set BEE_DEBUG_API_URL system environment variable with yours.

To run test execute

npm run test

Maintainers

See what "Maintainer" means here.