feat: allow user defined services (#375)

Adds types to libp2p to allow user defined services.

Removes all non-essential services to allow them to be defined
alongside any custom user versions.

This increases the modularity of libp2p as default protocols like
identify, fetch and ping will not be enabled unless specifically
allowed by the user, which also decreases the attack surface area
of libp2p applications.

BREAKING CHANGE: pubsub, dht, ping, fetch and identify have been removed - re-enable these by passing them as services

Author: achingbrain

packages/interface-libp2p/src/index.ts

@@ -18,13 +18,11 @@ import type { AbortOptions } from '@libp2p/interfaces'
 import type { EventEmitter } from '@libp2p/interfaces/events'
 import type { Startable } from '@libp2p/interfaces/startable'
 import type { Multiaddr } from '@multiformats/multiaddr'
-import type { DualDHT } from '@libp2p/interface-dht'
 import type { Address, Peer, PeerStore } from '@libp2p/interface-peer-store'
 import type { PeerId } from '@libp2p/interface-peer-id'
 import type { Connection, Stream } from '@libp2p/interface-connection'
 import type { PeerRouting } from '@libp2p/interface-peer-routing'
 import type { ContentRouting } from '@libp2p/interface-content-routing'
-import type { PubSub } from '@libp2p/interface-pubsub'
 import type { StreamHandler, StreamHandlerOptions, Topology } from '@libp2p/interface-registrar'
 import type { Metrics } from '@libp2p/interface-metrics'
 import type { PeerInfo } from '@libp2p/interface-peer-info'
@@ -91,7 +89,7 @@ export interface Libp2pEvents {
    *
    * ```js
    * libp2p.connectionManager.addEventListener('peer:disconnect', (event) => {
-   *   const connection = event.detail
+   *   const peerId = event.detail
    *   // ...
    * })
    * ```
@@ -157,11 +155,26 @@ export interface Libp2pEvents {
 }
 
 /**
- * Fetch service lookup function
+ * A map of user defined services available on the libp2p node via the
+ * `services` key
+ *
+ * @example
+ *
+ * ```js
+ * const node = await createLibp2p({
+ *   // ...other options
+ *   services: {
+ *     myService: myService({
+ *       // ...service options
+ *     })
+ *   }
+ * })
+ *
+ * // invoke methods on the service
+ * node.services.myService.anOperation()
+ * ```
  */
-export interface LookupFunction {
-  (key: string): Promise<Uint8Array | null>
-}
+export type ServiceMap = Record<string, unknown>
 
 export type PendingDialStatus = 'queued' | 'active' | 'error' | 'success'
 
@@ -195,7 +208,7 @@ export interface PendingDial {
 /**
  * Libp2p nodes implement this interface.
  */
-export interface Libp2p extends Startable, EventEmitter<Libp2pEvents> {
+export interface Libp2p<T extends ServiceMap = {}> extends Startable, EventEmitter<Libp2pEvents> {
   /**
    * The PeerId is a unique identifier for a node on the network.
    *
@@ -285,7 +298,7 @@ export interface Libp2p extends Startable, EventEmitter<Libp2pEvents> {
    * @example
    *
    * ```js
-   * const metric = libp2p.registerMetric({
+   * const metric = libp2p.metrics.registerMetric({
    *   'my-metric'
    * })
    *
@@ -295,98 +308,6 @@ export interface Libp2p extends Startable, EventEmitter<Libp2pEvents> {
    */
   metrics?: Metrics
 
-  /**
-   * The pubsub component implements a distributed [Publish-subscribe](https://en.wikipedia.org/wiki/Publish%E2%80%93subscribe_pattern)
-   * network made up of libp2p nodes listening on various topics.
-   *
-   * @example
-   *
-   * ```js
-   * libp2p.pubsub.addEventListener('message', (event) => {
-   *   // ...
-   * })
-   * libp2p.pubsub.subscribe('my-topic')
-   * ```
-   */
-  pubsub: PubSub
-
-  /**
-   * The [DHT](https://en.wikipedia.org/wiki/Distributed_hash_table) is used by
-   * libp2p to store and find values such as provider records and also to discover
-   * information about peers.
-   *
-   * @example
-   *
-   * ```js
-   * for await (const event of libp2p.dht.findPeer(peerId)) {
-   *   // ...
-   * }
-   * ```
-   */
-  dht: DualDHT
-
-  /**
-   * The fetch service allows registering and unregistering functions that supply
-   * values for fetch queries - see the [fetch spec](https://github.com/libp2p/specs/tree/master/fetch).
-   */
-  fetchService: {
-    /**
-     * Registers a new lookup callback that can map keys to values, for a given set of keys that
-     * share the same prefix
-     *
-     * @example
-     *
-     * ```js
-     * libp2p.fetchService.registerLookupFunction('/prefix', (key) => { ... })
-     * ```
-     */
-    registerLookupFunction: (prefix: string, lookup: LookupFunction) => void
-
-    /**
-     * Registers a new lookup callback that can map keys to values, for a given set of keys that
-     * share the same prefix.
-     *
-     * @example
-     *
-     * ```js
-     * libp2p.fetchService.unregisterLookupFunction('/prefix')
-     * ```
-     */
-    unregisterLookupFunction: (prefix: string, lookup?: LookupFunction) => void
-  }
-
-  /**
-   * The identify service supplies information about this node on request by network peers - see
-   * this [identify spec](https://github.com/libp2p/specs/blob/master/identify/README.md)
-   */
-  identifyService: {
-    host: {
-      /**
-       * Specifies the supported protocol version
-       *
-       * @example
-       *
-       * ```js
-       * libp2p.identifyService.host.protocolVersion
-       * // ipfs/0.1.0
-       * ```
-       */
-      protocolVersion: string
-
-      /**
-       * Specifies the supported protocol version
-       *
-       * @example
-       *
-       * ```js
-       * libp2p.identifyService.host.agentVersion
-       * // helia/1.0.0
-       * ```
-       */
-      agentVersion: string
-    }
-  }
-
   /**
    * Get a deduplicated list of peer advertising multiaddrs by concatenating
    * the listen addresses used by transports with any configured
@@ -569,31 +490,15 @@ export interface Libp2p extends Startable, EventEmitter<Libp2pEvents> {
    */
   unregister: (id: string) => void
 
-  /**
-   * Pings the given peer in order to obtain the operation latency
-   *
-   * @example
-   *
-   * ```js
-   * const latency = await libp2p.ping(otherPeerId)
-   * ```
-   */
-  ping: (peer: PeerId | Multiaddr, options?: AbortOptions) => Promise<number>
-
-  /**
-   * Sends a request to fetch the value associated with the given key from the given peer.
-   *
-   * @example
-   *
-   * ```js
-   * const value = await libp2p.fetch(otherPeerId, '/some/key')
-   * ```
-   */
-  fetch: (peer: PeerId | Multiaddr, key: string, options?: AbortOptions) => Promise<Uint8Array | null>
-
   /**
    * Returns the public key for the passed PeerId. If the PeerId is of the 'RSA' type
    * this may mean searching the DHT if the key is not present in the KeyStore.
+   * A set of user defined services
    */
   getPublicKey: (peer: PeerId, options?: AbortOptions) => Promise<Uint8Array>
+
+  /**
+   * A set of user defined services
+   */
+  services: T
 }