Implementation of the Fetch Protocol
An implementation of the Fetch protocol as described here: https://github.com/libp2p/specs/tree/master/fetch
The fetch protocol is a simple protocol for requesting a value corresponding to a key from a peer.
import { createLibp2p } from 'libp2p'
import { fetch } from '@libp2p/fetch'
import { peerIdFromString } from '@libp2p/peer-id'
const libp2p = await createLibp2p({
services: {
fetch: fetch()
}
})
// Given a key (as a string) returns a value (as a Uint8Array), or undefined
// if the key isn't found.
// All keys must be prefixed my the same prefix, which will be used to find
// the appropriate key lookup function.
async function my_subsystem_key_lookup (key: string): Promise<Uint8Array | undefined> {
// app specific callback to lookup key-value pairs.
return Uint8Array.from([0, 1, 2, 3, 4])
}
// Enable this peer to respond to fetch requests for keys that begin with
// '/my_subsystem_key_prefix/'
libp2p.services.fetch.registerLookupFunction('/my_subsystem_key_prefix/', my_subsystem_key_lookup)
const key = '/my_subsystem_key_prefix/{...}'
const peerDst = peerIdFromString('Qmfoo...')
// Load the value from the remote peer, timing out after 10s
const value = await libp2p.services.fetch.fetch(peerDst, key, {
signal: AbortSignal.timeout(10_000)
})$ npm i @libp2p/fetchLoading this module through a script tag will make it's exports available as Libp2pFetch in the global namespace.
<script src="https://unpkg.com/@libp2p/fetch/dist/index.min.js"></script>Licensed under either of
- Apache 2.0, (LICENSE-APACHE / http://www.apache.org/licenses/LICENSE-2.0)
- MIT (LICENSE-MIT / http://opensource.org/licenses/MIT)
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.