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API

Static Functions

create

Creates an instance of Libp2p.

create(options)

Parameters

Name Type Description
options object libp2p options
options.modules Array<object> libp2p modules to use
[options.addresses] { listen: Array<string>, announce: Array<string>, announceFilter: (ma: Array<multiaddr>) => Array<multiaddr> } Addresses for transport listening and to advertise to the network
[options.config] object libp2p modules configuration and core configuration
[options.identify] { protocolPrefix: string, host: { agentVersion: string }, timeout: number } libp2p identify protocol options
[options.ping] { protocolPrefix: string } libp2p ping protocol options
[options.fetch] { protocolPrefix: string } libp2p fetch protocol options
[options.connectionManager] object libp2p Connection Manager configuration
[options.transportManager] object libp2p transport manager configuration
[options.datastore] object must implement ipfs/interface-datastore (in memory datastore will be used if not provided)
[options.dialer] object libp2p Dialer configuration
[options.keychain] object keychain configuration
[options.metrics] object libp2p Metrics configuration
[options.peerId] PeerId peerId instance (it will be created if not provided)
[options.peerRouting] object libp2p Peer routing service configuration
[options.peerStore] object libp2p PeerStore configuration

For Libp2p configurations and modules details read the Configuration Document.

Returns

Type Description
Promise<Libp2p> Promise resolves with the Libp2p instance

Example

import { createLibp2p } from 'libp2p'
import { TCP } from '@libp2p/tcp'
import { Mplex } from '@libp2p/mplex'
import { Noise } from '@chainsafe/libp2p-noise'

async function main () {
  // specify options
  const options = {
    transports: [new TCP()],
    streamMuxers: [new Mplex()],
    connectionEncryption: [new Noise()]
  }

  // create libp2p
  const libp2p = await createLibp2p(options)
}

main()

Note: The PeerId option is not required and will be generated if it is not provided.

Alternative As an alternative, it is possible to create a Libp2p instance with the constructor:

Example

import { createLibp2p } from 'libp2p'
import { TCP } from '@libp2p/tcp'
import { Mplex } from '@libp2p/mplex'
import { Noise } from '@chainsafe/libp2p-noise'


async function main () {
  const peerId = await PeerId.create();

  // specify options
  // peerId is required when Libp2p is instantiated via the constructor
  const options = {
    peerId,
    transports: [new TCP()],
    streamMuxers: [new Mplex()],
    connectionEncryption: [new Noise()]
  }

  // create libp2p
  const libp2p = new Libp2p(options)
}

main()

Required keys in the options object:

Libp2p Instance Methods

loadKeychain

Load keychain keys from the datastore, importing the private key as 'self', if needed.

libp2p.loadKeychain()

Returns

Type Description
Promise Promise resolves when the keychain is ready

Example

import { createLibp2p } from 'libp2p'

// ...

const libp2p = await createLibp2p({
  // ...
  keychain: {
    pass: '0123456789pass1234567890'
  }
})

// load keychain
await libp2p.loadKeychain()

start

Starts the libp2p node.

libp2p.start()

Returns

Type Description
Promise Promise resolves when the node is ready

Example

import { createLibp2p } from 'libp2p'

// ...

const libp2p = await createLibp2p(options)

// start libp2p
await libp2p.start()

stop

Stops the libp2p node.

libp2p.stop()

Returns

Type Description
Promise Promise resolves when the node is fully stopped

Example

import { createLibp2p } from 'libp2p'

// ...
const libp2p = await createLibp2p(options)
// ...

// stop libp2p
await libp2p.stop()

addresses

TODO with address-manager.

connections

A Getter that returns a Map of the current Connections libp2p has to other peers.

libp2p.connections

Returns

Type Description
Map<string, Array<Connection>> A map of PeerId strings to Connection Arrays

Example

for (const [peerId, connections] of libp2p.connections) {
  for (const connection of connections) {
    console.log(peerId, connection.remoteAddr.toString())
    // Logs the PeerId string and the observed remote multiaddr of each Connection
  }
}

dial

dial(peer, options)

Parameters

Name Type Description
peer PeerId|Multiaddr|string The peer to dial.
[options] object dial options
[options.signal] AbortSignal An AbortSignal instance obtained from an AbortController that can be used to abort the connection before it completes

Note: If a Multiaddr or its string is provided, it must include the peer id. Moreover, if a PeerId is given, the peer will need to have known multiaddrs for it in the PeerStore.

Returns

Type Description
Promise<Connection> Promise resolves with the Connection instance

Example

// ...
const conn = await libp2p.dial(remotePeerId)

// create a new stream within the connection
const { stream, protocol } = await conn.newStream(['/echo/1.1.0', '/echo/1.0.0'])

// protocol negotiated: 'echo/1.0.0' means that the other party only supports the older version

// ...
await conn.close()

dialProtocol

Dials to another peer in the network and selects a protocol to communicate with that peer. The stream between both parties is returned, together with the negotiated protocol.

dialProtocol(peer, protocols, options)

Parameters

Name Type Description
peer PeerId|Multiaddr|string The peer to dial.
protocols `string Array`
[options] object dial options
[options.signal] AbortSignal An AbortSignal instance obtained from an AbortController that can be used to abort the connection before it completes

Note: If a Multiaddr or its string is provided, it must include the peer id. Moreover, if a PeerId is given, the peer will need to have known multiaddrs for it in the PeerStore.

Returns

Type Description
Promise<{ stream:*, protocol:string }> Promise resolves with a duplex stream and the protocol used

Example

// ...
import { pipe } from 'it-pipe'

const { stream, protocol } = await libp2p.dialProtocol(remotePeerId, protocols)

// Use this new stream like any other duplex stream
pipe([1, 2, 3], stream, consume)

hangUp

Attempts to gracefully close an open connection to the given peer. If the connection is not closed in the grace period, it will be forcefully closed.

hangUp(peer)

Parameters

Name Type Description
peer PeerId|Multiaddr|string peer to hang up

Returns

Type Description
Promise<void> Promise resolves once connection closes

Example

// ...
await libp2p.hangUp(remotePeerId)

handle

Sets up multistream-select routing of protocols to their application handlers. Whenever a stream is opened on one of the provided protocols, the handler will be called. handle must be called in order to register a handler and support for a given protocol. This also informs other peers of the protocols you support.

libp2p.handle(protocols, handler)

In the event of a new handler for the same protocol being added, the first one is discarded.

Parameters

Name Type Description
protocols `Array string`
handler function({ connection:*, stream:*, protocol:string }) handler to call

Example

// ...
const handler = ({ connection, stream, protocol }) => {
  // use stream or connection according to the needs
}

libp2p.handle('/echo/1.0.0', handler)

unhandle

Unregisters all handlers with the given protocols

libp2p.unhandle(protocols)

Parameters

Name Type Description
protocols `Array string`

Example

// ...
libp2p.unhandle(['/echo/1.0.0'])

ping

Pings a given peer and get the operation's latency.

libp2p.ping(peer)

Parameters

Name Type Description
peer PeerId|Multiaddr|string peer to ping

Returns

Type Description
Promise<number> Latency of the operation in ms

Example

// ...
const latency = await libp2p.ping(otherPeerId)

fetch

Fetch a value from a remote node

libp2p.fetch(peer, key)

Parameters

Name Type Description
peer PeerId|Multiaddr|string peer to ping
key string A key that corresponds to a value on the remote node

Returns

Type Description
`Promise<Uint8Array null>`

Example

// ...
const value = await libp2p.fetch(otherPeerId, '/some/key')

fetchService.registerLookupFunction

Register a function to look up values requested by remote nodes

libp2p.fetchService.registerLookupFunction(prefix, lookup)

Parameters

Name Type Description
prefix string All queries below this prefix will be passed to the lookup function
lookup `(key: string) => Promise<Uint8Array null>`

Example

// ...
const value = await libp2p.fetchService.registerLookupFunction('/prefix', (key) => { ... })

fetchService.unregisterLookupFunction

Removes the passed lookup function or any function registered for the passed prefix

libp2p.fetchService.unregisterLookupFunction(prefix, lookup)

Parameters

Name Type Description
prefix string All queries below this prefix will be passed to the lookup function
lookup `(key: string) => Promise<Uint8Array null>`

Example

// ...
libp2p.fetchService.unregisterLookupFunction('/prefix')

multiaddrs

Gets the multiaddrs the libp2p node announces to the network. This computes the advertising multiaddrs of the peer by joining the multiaddrs that libp2p transports are listening on with the announce multiaddrs provided in the libp2p config. Configured no announce multiaddrs will be filtered out of the advertised addresses.

libp2p.multiaddrs

Returns

Type Description
Array<Multiaddr> Advertising multiaddrs

Example

// ...
const listenMa = libp2p.multiaddrs
// [ <Multiaddr 047f00000106f9ba - /ip4/127.0.0.1/tcp/63930> ]

addressManager.getListenAddrs

Get the multiaddrs that were provided for listening on libp2p transports.

libp2p.addressManager.getListenAddrs()

Returns

Type Description
Array<Multiaddr> Provided listening multiaddrs

Example

// ...
const listenMa = libp2p.addressManager.getListenAddrs()
// [ <Multiaddr 047f00000106f9ba - /ip4/127.0.0.1/tcp/63930> ]

addressManager.getAnnounceAddrs

Get the multiaddrs that were provided to announce to the network.

libp2p.addressManager.getAnnounceAddrs()

Returns

Type Description
Array<Multiaddr> Provided announce multiaddrs

Example

// ...
const announceMa = libp2p.addressManager.getAnnounceAddrs()
// [ <Multiaddr 047f00000106f9ba - /dns4/peer.io/...> ]

transportManager.getAddrs

Get the multiaddrs that libp2p transports are using to listen on.

libp2p.transportManager.getAddrs()

Returns

Type Description
Array<Multiaddr> listening multiaddrs

Example

// ...
const listenMa = libp2p.transportManager.getAddrs()
// [ <Multiaddr 047f00000106f9ba - /ip4/127.0.0.1/tcp/63930> ]

contentRouting.findProviders

Iterates over all content routers in series to find providers of the given key. Once a content router succeeds, the iteration will stop. If the DHT is enabled, it will be queried first.

libp2p.contentRouting.findProviders(cid, options)

Parameters

Name Type Description
cid CID cid to find
options object operation options
options.timeout number maximum time the query should run
options.maxNumProviders number maximum number of providers to find

Returns

Type Description
AsyncIterable<{ id: PeerId, multiaddrs: Multiaddr[] } Async iterator for peer data

Example

// Iterate over the providers found for the given cid
for await (const provider of libp2p.contentRouting.findProviders(cid)) {
  console.log(provider.id, provider.multiaddrs)
}

contentRouting.provide

Iterates over all content routers in parallel, in order to notify it is a provider of the given key.

libp2p.contentRouting.provide(cid)

Parameters

Name Type Description
cid CID cid to provide

Returns

Type Description
Promise<void> Promise resolves once notifications are sent

Example

// ...
await libp2p.contentRouting.provide(cid)

contentRouting.put

Writes a value to a key in the DHT.

libp2p.contentRouting.put(key, value, options)

Parameters

Name Type Description
key string key to add to the dht
value Uint8Array value to add to the dht
[options] object put options
[options.minPeers] number minimum number of peers required to successfully put (default: closestPeers.length)

Returns

Type Description
Promise<void> Promise resolves once value is stored

Example

// ...
const key = '/key'
const value = uint8ArrayFromString('oh hello there')

await libp2p.contentRouting.put(key, value)

contentRouting.get

Queries the DHT for a value stored for a given key.

libp2p.contentRouting.get(key, options)

Parameters

Name Type Description
key string key to get from the dht
[options] object get options
[options.timeout] number maximum time the query should run

Returns

Type Description
Promise<Uint8Array> Value obtained from the DHT

Example

// ...

const key = '/key'
const value = await libp2p.contentRouting.get(key)

contentRouting.getMany

Queries the DHT for the n values stored for the given key (without sorting).

libp2p.contentRouting.getMany(key, nvals, options)

Parameters

Name Type Description
key string key to get from the dht
nvals number number of values aimed
[options] object get options
[options.timeout] number maximum time the query should run

Returns

Type Description
Promise<Array<{from: PeerId, val: Uint8Array}>> Array of records obtained from the DHT

Example

// ...

const key = '/key'
const records = await libp2p.contentRouting.getMany(key, 2)

peerRouting.findPeer

Iterates over all peer routers in series to find the given peer. If the DHT is enabled, it will be tried first.

libp2p.peerRouting.findPeer(peerId, options)

Parameters

Name Type Description
peerId PeerId ID of the peer to find
options object operation options
options.timeout number maximum time the query should run

Returns

Type Description
Promise<{ id: PeerId, multiaddrs: Multiaddr[] }> Peer data of a known peer

Example

// ...
const peer = await libp2p.peerRouting.findPeer(peerId, options)

peerRouting.getClosestPeers

Iterates over all content routers in series to get the closest peers of the given key. Once a content router succeeds, the iteration will stop. If the DHT is enabled, it will be queried first.

libp2p.peerRouting.getClosestPeers(cid, options)

Parameters

Name Type Description
key Uint8Array A CID like key
options object operation options
options.timeout number How long the query can take (ms).

Returns

Type Description
AsyncIterable<{ id: PeerId, multiaddrs: Multiaddr[] } Async iterator for peer data

Example

// Iterate over the closest peers found for the given key
for await (const peer of libp2p.peerRouting.getClosestPeers(key)) {
  console.log(peer.id, peer.multiaddrs)
}

peerStore.addressBook.add

Adds known multiaddrs of a given peer. If the peer is not known, it will be set with the provided multiaddrs.

peerStore.addressBook.add(peerId, multiaddrs)

Parameters

Name Type Description
peerId PeerId peerId to set
multiaddrs Array<Multiaddr>

Returns

Type Description
AddressBook Returns the Address Book component

Example

peerStore.addressBook.add(peerId, multiaddr)

peerStore.addressBook.delete

Delete the provided peer from the book.

peerStore.addressBook.delete(peerId)

Parameters

Name Type Description
peerId PeerId peerId to remove

Returns

Type Description
boolean true if found and removed

Example

peerStore.addressBook.delete(peerId)
// false
peerStore.addressBook.set(peerId, multiaddr)
peerStore.addressBook.delete(peerId)
// true

peerStore.addressBook.get

Get the known Addresses of a provided peer.

peerStore.addressBook.get(peerId)

Parameters

Name Type Description
peerId PeerId peerId to get

Returns

Type Description
`Array undefined`

Example

peerStore.addressBook.get(peerId)
// undefined
peerStore.addressBook.set(peerId, multiaddr)
peerStore.addressBook.get(peerId)
// [
// {
//   multiaddr: /ip4/140.10.2.1/tcp/8000,
//   ...
// },
// {
//   multiaddr: /ip4/140.10.2.1/ws/8001
//   ...
// },
// ]

peerStore.addressBook.getMultiaddrsForPeer

Get the known Multiaddr of a provided peer. All returned multiaddrs will include the encapsulated PeerId of the peer.

peerStore.addressBook.getMultiaddrsForPeer(peerId)

Parameters

Name Type Description
peerId PeerId peerId to get

Returns

Type Description
`Array undefined`

Example

peerStore.addressBook.getMultiaddrsForPeer(peerId)
// undefined
peerStore.addressBook.set(peerId, multiaddr)
peerStore.addressBook.getMultiaddrsForPeer(peerId)
// [
// /ip4/140.10.2.1/tcp/8000/p2p/QmW8rAgaaA6sRydK1k6vonShQME47aDxaFidbtMevWs73t
// /ip4/140.10.2.1/ws/8001/p2p/QmW8rAgaaA6sRydK1k6vonShQME47aDxaFidbtMevWs73t
// ]

peerStore.addressBook.set

Set known multiaddrs of a given peer. This will replace previously stored multiaddrs, if available. Replacing stored multiaddrs might result in losing obtained certified addresses, which is not desirable. Consider using addressBook.add() if you're not sure this is what you want to do.

peerStore.addressBook.set(peerId, multiaddrs)

Parameters

Name Type Description
peerId PeerId peerId to set
multiaddrs Array<Multiaddr>

Returns

Type Description
AddressBook Returns the Address Book component

Example

peerStore.addressBook.add(peerId, multiaddr)

peerStore.keyBook.delete

Delete the provided peer from the book.

peerStore.keyBook.delete(peerId)

Parameters

Name Type Description
peerId PeerId peerId to remove

Returns

Type Description
boolean true if found and removed

Example

peerStore.keyBook.delete(peerId)
// false
peerStore.keyBook.set(peerId, publicKey)
peerStore.keyBook.delete(peerId)
// true

peerStore.keyBook.get

Get the known PublicKey of a provided peer.

peerStore.keyBook.get(peerId)

Parameters

Name Type Description
peerId PeerId peerId to get

Returns

Type Description
RsaPublicKey|Ed25519PublicKey|Secp256k1PublicKey Peer PublicKey

Example

peerStore.keyBook.get(peerId)
// undefined
peerStore.keyBook.set(peerId, publicKey)
peerStore.keyBook.get(peerId)
// PublicKey

peerStore.keyBook.set

Set known peerId. This can include its Public Key.

peerStore.keyBook.set(peerId, publicKey)

Parameters

Name Type Description
peerId PeerId peerId to set
publicKey RsaPublicKey|Ed25519PublicKey|Secp256k1PublicKey peer's public key

Returns

Type Description
KeyBook Returns the Key Book component

Example

const publicKey = peerId.pubKey
peerStore.keyBook.set(peerId, publicKey)

peerStore.metadataBook.delete

Delete the provided peer from the book.

peerStore.metadataBook.delete(peerId)

Parameters

Name Type Description
peerId PeerId peerId to remove

Returns

Type Description
boolean true if found and removed

Example

peerStore.metadataBook.delete(peerId)
// false
peerStore.metadataBook.set(peerId, 'nickname', uint8ArrayFromString('homePeer'))
peerStore.metadataBook.delete(peerId)
// true

peerStore.metadataBook.deleteValue

Deletes the provided peer metadata key-value pair from the book.

peerStore.metadataBook.deleteValue(peerId, key)

Parameters

Name Type Description
peerId PeerId peerId to remove
key string key of the metadata value to remove

Returns

Type Description
boolean true if found and removed

Example

peerStore.metadataBook.deleteValue(peerId, 'location')
// false
peerStore.metadataBook.set(peerId, 'location', uint8ArrayFromString('Berlin'))
peerStore.metadataBook.deleteValue(peerId, 'location')
// true

peerStore.metadataBook.get

Get the known metadata of a provided peer.

peerStore.metadataBook.get(peerId)

Parameters

Name Type Description
peerId PeerId peerId to get

Returns

Type Description
Map<string, Uint8Array> Peer Metadata

Example

peerStore.metadataBook.get(peerId)
// undefined
peerStore.metadataBook.set(peerId, 'location', uint8ArrayFromString('Berlin'))
peerStore.metadataBook.get(peerId)
// Metadata Map

peerStore.metadataBook.getValue

Get specific metadata of a provided peer.

peerStore.metadataBook.getValue(peerId)

Parameters

Name Type Description
peerId PeerId peerId to get
key string key of the metadata value to get

Returns

Type Description
Map<string, Uint8Array> Peer Metadata

Example

peerStore.metadataBook.getValue(peerId, 'location')
// undefined
peerStore.metadataBook.set(peerId, 'location', uint8ArrayFromString('Berlin'))
peerStore.metadataBook.getValue(peerId, 'location')
// Metadata Map

peerStore.metadataBook.set

Set known metadata of a given peerId.

peerStore.metadataBook.set(peerId, key, value)

Parameters

Name Type Description
peerId PeerId peerId to set
key string key of the metadata value to store
value Uint8Array metadata value to store

Returns

Type Description
MetadataBook Returns the Metadata Book component

Example

peerStore.metadataBook.set(peerId, 'location', uint8ArrayFromString('Berlin'))

peerStore.protoBook.add

Add known protocols of a given peer.

peerStore.protoBook.add(peerId, protocols)

Parameters

Name Type Description
peerId PeerId peerId to set
protocols Array<string> protocols to add

Returns

Type Description
ProtoBook Returns the Proto Book component

Example

peerStore.protoBook.add(peerId, protocols)

peerStore.protoBook.delete

Delete the provided peer from the book.

peerStore.protoBook.delete(peerId)

Parameters

Name Type Description
peerId PeerId peerId to remove

Returns

Type Description
boolean true if found and removed

Example

peerStore.protoBook.delete(peerId)
// false
peerStore.protoBook.set(peerId, protocols)
peerStore.protoBook.delete(peerId)
// true

peerStore.protoBook.get

Get the known protocols of a provided peer.

peerStore.protoBook.get(peerId)

Parameters

Name Type Description
peerId PeerId peerId to get

Returns

Type Description
Array<string> Array of peer's supported protocols

Example

peerStore.protoBook.get(peerId)
// undefined
peerStore.protoBook.set(peerId, [ '/proto/1.0.0', '/proto/1.1.0' ])
peerStore.protoBook.get(peerId)
// [ '/proto/1.0.0', '/proto/1.1.0' ]

peerStore.protoBook.remove

Remove given protocols of a given peer.

peerStore.protoBook.remove(peerId, protocols)

Parameters

Name Type Description
peerId PeerId peerId to set
protocols Array<string> protocols to remove

Returns

Type Description
ProtoBook Returns the Proto Book component

Example

peerStore.protoBook.remove(peerId, protocols)

peerStore.protoBook.set

Set known protocols of a given peer.

peerStore.protoBook.set(peerId, protocols)

Parameters

Name Type Description
peerId PeerId peerId to set
protocols Array<string> protocols to store

Returns

Type Description
ProtoBook Returns the Proto Book component

Example

peerStore.protoBook.set(peerId, protocols)

peerStore.delete

Delete the provided peer from every book.

peerStore.delete(peerId)

Parameters

Name Type Description
peerId PeerId peerId to remove

Returns

Type Description
boolean true if found and removed

Example

peerStore.delete(peerId)
// false
peerStore.addressBook.set(peerId, multiaddrs)
peerStore.protoBook.set(peerId, protocols)
peerStore.delete(peerId)
// true
peerStore.delete(peerId2)
// false
peerStore.addressBook.set(peerId2, multiaddrs)
peerStore.delete(peerId2)
// true

peerStore.get

Get the stored information of a given peer, namely its PeerId, known Addresses and supported protocols.

peerStore.get(peerId)

Parameters

Name Type Description
peerId PeerId peerId to get

Returns

Type Description
{ id: PeerId, addresses: Array<Address>, metadata: Map<string, Buffer>}, protocols: Array<string> } Peer information of the provided peer

Example

peerStore.get(peerId)
// false
peerStore.addressBook.set(peerId, multiaddrs)
peerStore.protoBook.set(peerId, protocols)
peerStore.get(peerId)
// {
//   id: {},
//   addresses: [...],
//   protocols: [...]
// }

peerStore.peers

Get all the stored information of every peer.

peerStore.peers

Returns

Type Description
Map<string, { id: PeerId, addresses: Array<Address>, metadata: Map<string, Buffer>}, protocols: Array<string> }> Peer data of every peer known

Example

for (let [peerIdString, peer] of peerStore.peers.entries()) {
  // peer { id, addresses, metadata, protocols }
}

pubsub.getSubscribers

Gets a list of the peer-ids that are subscribed to one topic.

libp2p.pubsub.getSubscribers(topic)

Parameters

Name Type Description
topic string topic to publish

Returns

Type Description
Array<string> peer-id subscribed to the topic

Example

const peerIds = libp2p.pubsub.getSubscribers(topic)

pubsub.getTopics

Gets a list of topics the node is subscribed to.

libp2p.pubsub.getTopics()

Returns

Type Description
Array<string> topics the node is subscribed to

Example

const topics = libp2p.pubsub.getTopics()

pubsub.publish

Publishes messages to the given topics.

libp2p.pubsub.publish(topic, data)

Parameters

Name Type Description
topic string topic to publish
data Uint8Array data to publish

Returns

Type Description
Promise publish success

Example

const topic = 'topic'
const data = uint8ArrayFromString('data')

await libp2p.pubsub.publish(topic, data)

pubsub.subscribe

Subscribes to a pubsub topic.

libp2p.pubsub.subscribe(topic)

Parameters

Name Type Description
topic string topic to subscribe

Returns

Type Description
void

Example

const topic = 'topic'
const handler = (msg) => {
  // msg.data - pubsub data received
}

libp2p.pubsub.on(topic, handler)
libp2p.pubsub.subscribe(topic)

pubsub.unsubscribe

Unsubscribes from a pubsub topic.

libp2p.pubsub.unsubscribe(topic)

Parameters

Name Type Description
topic string topic to unsubscribe

Returns

Type Description
void

Example

const topic = 'topic'
const handler = (msg) => {
  // msg.data - pubsub data received
}

libp2p.pubsub.removeListener(topic handler)
libp2p.pubsub.unsubscribe(topic)

pubsub.on

A Pubsub router is an EventEmitter and uses its events for pubsub message handlers.

libp2p.pubsub.on(topic, handler)

Parameters

Name Type Description
topic string topic to listen
handler function({ from: string, data: Uint8Array, seqno: Uint8Array, topicIDs: Array<string>, signature: Uint8Array, key: Uint8Array }) handler for new data on topic

Returns

Type Description
void

Example

const topic = 'topic'
const handler = (msg) => {
  // msg.data - pubsub data received
}

libp2p.pubsub.on(topic, handler)
libp2p.pubsub.subscribe(topic)

pubsub.removeListener

A Pubsub router is an EventEmitter and uses its events for pubsub message handlers.

libp2p.pubsub.removeListener(topic, handler)

Parameters

Name Type Description
topic string topic to remove listener
handler function({ from: string, data: Uint8Array, seqno: Uint8Array, topicIDs: Array<string>, signature: Uint8Array, key: Uint8Array }) handler for new data on topic

Returns

Type Description
void

Example

const topic = 'topic'
const handler = (msg) => {
  // msg.data - pubsub data received
}

libp2p.pubsub.removeListener(topic handler)
libp2p.pubsub.unsubscribe(topic)

pubsub.topicValidators.set

Pubsub routers support message validators per topic, which will validate the message before its propagations. Set is used to specify a validator for a topic.

libp2p.pubsub.topicValidators.set(topic, validator)

Parameters

Name Type Description
topic string topic to bind a validator
handler function({ topic: string, msg: RPC }) validator for new data on topic

Returns

Type Description
Map<string, function(string, RPC)> The Map object

Example

const topic = 'topic'
const validateMessage = (msgTopic, msg) => {
  const input = uint8ArrayToString(msg.data)
  const validInputs = ['a', 'b', 'c']

  if (!validInputs.includes(input)) {
    throw new Error('no valid input received')
  }
}
libp2p.pubsub.topicValidators.set(topic, validateMessage)

pubsub.topicValidators.delete

Pubsub routers support message validators per topic, which will validate the message before its propagations. Delete is used to remove a validator for a topic.

libp2p.pubsub.topicValidators.delete(topic)

Parameters

Name Type Description
topic string topic to remove a validator

Returns

Type Description
boolean true if an element in the Map object existed and has been removed, or false if the element does not exist.

Example

const topic = 'topic'
libp2p.pubsub.topicValidators.delete(topic)

connectionManager.get

Get a connection with a given peer, if it exists.

Parameters

Name Type Description
peerId PeerId The peer to find

Returns

Type Description
Connection Connection with the given peer

Example

libp2p.connectionManager.get(peerId)

connectionManager.setPeerValue

Enables users to change the value of certain peers in a range of 0 to 1. Peers with the lowest values will have their Connections pruned first, if any Connection Manager limits are exceeded. See ./CONFIGURATION.md#configuring-connection-manager for details on how to configure these limits.

libp2p.connectionManager.setPeerValue(peerId, value)

Parameters

Name Type Description
peerId PeerId The peer to set the value for
value number The value of the peer from 0 to 1

Returns

Type Description
void

Example

libp2p.connectionManager.setPeerValue(highPriorityPeerId, 1)
libp2p.connectionManager.setPeerValue(lowPriorityPeerId, 0)

connectionManager.size

Getter for obtaining the current number of open connections.

Example

libp2p.connectionManager.size
// 10

keychain.createKey

Create a key in the keychain.

libp2p.keychain.createKey(name, type, size)

Parameters

Name Type Description
name string The local key name. It cannot already exist.
type string One of the key types; 'rsa'
[size] number The key size in bits. Must be provided for rsa keys.

Returns

Type Description
Promise<{ id, name }> Key info object

Example

const keyInfo = await libp2p.keychain.createKey('keyTest', 'rsa', 4096)

keychain.renameKey

Rename a key in the keychain.

libp2p.keychain.renameKey(oldName, newName)

Parameters

Name Type Description
name string The old local key name. It must already exist.
type string The new local key name. It must not already exist.

Returns

Type Description
Promise<{ id, name }> Key info object

Example

await libp2p.keychain.createKey('keyTest', 'rsa', 4096)
const keyInfo = await libp2p.keychain.renameKey('keyTest', 'keyNewNtest')

keychain.removeKey

Removes a key from the keychain.

libp2p.keychain.removeKey(name)

Parameters

Name Type Description
name string The local key name. It must already exist.

Returns

Type Description
Promise<{ id, name }> Key info object

Example

await libp2p.keychain.createKey('keyTest', 'rsa', 4096)
const keyInfo = await libp2p.keychain.removeKey('keyTest')

keychain.exportKey

Export an existing key as a PEM encrypted PKCS #8 string.

libp2p.keychain.exportKey(name, password)

Parameters

Name Type Description
name string The local key name. It must already exist.
password string The password to use.

Returns

Type Description
Promise<string> Key as a PEM encrypted PKCS #8

Example

await libp2p.keychain.createKey('keyTest', 'rsa', 4096)
const pemKey = await libp2p.keychain.exportKey('keyTest', 'password123')

keychain.importKey

Import a new key from a PEM encoded PKCS #8 string.

libp2p.keychain.importKey(name, pem, password)

Parameters

Name Type Description
name string The local key name. It must not exist.
pem string The PEM encoded PKCS #8 string.
password string The password to use.

Returns

Type Description
Promise<{ id, name }> Key info object

Example

await libp2p.keychain.createKey('keyTest', 'rsa', 4096)
const pemKey = await libp2p.keychain.exportKey('keyTest', 'password123')
const keyInfo = await libp2p.keychain.importKey('keyTestImport', pemKey, 'password123')

keychain.importPeer

Import a new key from a PeerId.

libp2p.keychain.importPeer(name, peerId)

Parameters

Name Type Description
name string The local key name. It must not exist.
peerId 'PeerId' The PEM encoded PKCS #8 string.

Returns

Type Description
Promise<{ id, name }> Key info object

Example

const keyInfo = await libp2p.keychain.importPeer('keyTestImport', peerId)

keychain.listKeys

List all the keys.

libp2p.keychain.listKeys()

Returns

Type Description
Promise<Array<{ id, name }>> Array of Key info

Example

const keyInfos = await libp2p.keychain.listKeys()

keychain.findKeyById

Find a key by it's id.

libp2p.keychain.findKeyById(id)

Parameters

Name Type Description
id string The universally unique key identifier.

Returns

Type Description
Promise<{ id, name }> Key info object

Example

const keyInfo = await libp2p.keychain.createKey('keyTest', 'rsa', 4096)
const keyInfo2 = await libp2p.keychain.findKeyById(keyInfo.id)

keychain.findKeyByName

Find a key by it's name.

libp2p.keychain.findKeyByName(id)

Parameters

Name Type Description
id string The local key name.

Returns

Type Description
Promise<{ id, name }> Key info object

Example

const keyInfo = await libp2p.keychain.createKey('keyTest', 'rsa', 4096)
const keyInfo2 = await libp2p.keychain.findKeyByName('keyTest')

keychain.cms.encrypt

Encrypt protected data using the Cryptographic Message Syntax (CMS).

libp2p.keychain.cms.encrypt(name, data)

Parameters

Name Type Description
name string The local key name.
data Uint8Array The data to encrypt.

Returns

Type Description
Promise<Uint8Array> Encrypted data as a PKCS #7 message in DER.

Example

const keyInfo = await libp2p.keychain.createKey('keyTest', 'rsa', 4096)
const enc = await libp2p.keychain.cms.encrypt('keyTest', uint8ArrayFromString('data'))

keychain.cms.decrypt

Decrypt protected data using the Cryptographic Message Syntax (CMS). The keychain must contain one of the keys used to encrypt the data. If none of the keys exists, an Error is returned with the property 'missingKeys'.

libp2p.keychain.cms.decrypt(cmsData)

Parameters

Name Type Description
cmsData string The CMS encrypted data to decrypt.

Returns

Type Description
Promise<Uint8Array> Decrypted data.

Example

const keyInfo = await libp2p.keychain.createKey('keyTest', 'rsa', 4096)
const enc = await libp2p.keychain.cms.encrypt('keyTest', uint8ArrayFromString('data'))
const decData = await libp2p.keychain.cms.decrypt(enc)

metrics.global

A Stats object of tracking the global bandwidth of the libp2p node.

Example

const peerIdStrings = libp2p.metrics.peers

metrics.peers

An array of PeerId strings of each peer currently being tracked.

Example

const peerIdStrings = libp2p.metrics.peers

metrics.protocols

An array of protocol strings that are currently being tracked.

Example

const protocols = libp2p.metrics.protocols

metrics.forPeer

Returns the Stats object for a given PeerId if it is being tracked.

libp2p.metrics.forPeer(peerId)

Parameters

Name Type Description
peerId PeerId The peer to get stats for

Returns

Type Description
Stats The bandwidth stats of the peer

Example

const peerStats = libp2p.metrics.forPeer(peerId)
console.log(peerStats.toJSON())

metrics.forProtocol

Returns the Stats object for a given protocol if it is being tracked.

libp2p.metrics.forProtocol(protocol)

Parameters

Name Type Description
protocol string The protocol to get stats for

Returns

Type Description
Stats The bandwidth stats of the protocol across all peers

Example

const peerStats = libp2p.metrics.forProtocol('/meshsub/1.0.0')
console.log(peerStats.toJSON())

Events

Once you have a libp2p instance, you can listen to several events it emits, so that you can be notified of relevant network events.

libp2p

An error has occurred

libp2p.on('error', (err) => {})

  • err: instance of Error

A peer has been discovered

libp2p.on('peer:discovery', (peer) => {})

If autoDial option is true, applications should not attempt to connect to the peer unless they are performing a specific action. See peer discovery and auto dial for more information.

libp2p.connectionManager

A new connection to a peer has been opened

This event will be triggered anytime a new Connection is established to another peer.

libp2p.connectionManager.on('peer:connect', (connection) => {})

An existing connection to a peer has been closed

This event will be triggered anytime we are disconnected from another peer, regardless of the circumstances of that disconnection. If we happen to have multiple connections to a peer, this event will only be triggered when the last connection is closed.

libp2p.connectionManager.on('peer:disconnect', (connection) => {})

libp2p.peerStore

A new peer is added to the peerStore

libp2p.peerStore.on('peer', (peerId) => {})

Known multiaddrs for a peer change

libp2p.peerStore.on('change:multiaddrs', ({ peerId, multiaddrs}) => {})

  • peerId: instance of PeerId
  • multiaddrs: array of known multiaddr for the peer

Known protocols for a peer change

libp2p.peerStore.on('change:protocols', ({ peerId, protocols}) => {})

  • peerId: instance of PeerId
  • protocols: array of known, supported protocols for the peer (string identifiers)

libp2p.addressManager

Our addresses have changed

This could be in response to a peer telling us about addresses they have observed, or the NatManager performing NAT hole punching.

libp2p.addressManager.on('change:addresses', () => {})

Types

Stats

  • Stats
    • toJSON<function()>: Returns a JSON snapshot of the stats.
      • dataReceived<string>: The stringified value of total incoming data for this stat.
      • dataSent<string>: The stringified value of total outgoing data for this stat.
      • movingAverages<object>: The properties are dependent on the configuration of the moving averages interval. Defaults are listed here.
        • ['60000']<number>: The calculated moving average at a 1 minute interval.
        • ['300000']<number>: The calculated moving average at a 5 minute interval.
        • ['900000']<number>: The calculated moving average at a 15 minute interval.
    • snapshot<object>: A getter that returns a clone of the raw stats.
      • dataReceived<BigNumber>: A BigNumber of the amount of incoming data
      • dataSent<BigNumber>: A BigNumber of the amount of outgoing data
    • movingAverages<object>: A getter that returns a clone of the raw moving averages stats. Note: The properties of this are dependent on configuration. The defaults are shown here.
      • ['60000']<MovingAverage>: The MovingAverage at a 1 minute interval.
      • ['300000']<MovingAverage>: The MovingAverage at a 5 minute interval.
      • ['900000']<MovingAverage>: The MovingAverage at a 15 minute interval.