Files
snort/packages/nostr/src/client/index.ts
2023-07-22 19:37:46 +01:00

335 lines
9.0 KiB
TypeScript

import { NostrError } from "../common"
import { RawEvent, parseEvent } from "../event"
import { Conn } from "./conn"
import * as utils from "@noble/curves/abstract/utils"
import { EventEmitter } from "./emitter"
import { fetchRelayInfo, ReadyState, Relay } from "./relay"
import { Filters } from "../filters"
/**
* A nostr client.
*
* TODO Document the events here
* TODO When document this type, remember to explicitly say that promise rejections will also be routed to "error"!
*/
export class Nostr extends EventEmitter {
static get CONNECTING(): ReadyState.CONNECTING {
return ReadyState.CONNECTING
}
static get OPEN(): ReadyState.OPEN {
return ReadyState.OPEN
}
static get CLOSED(): ReadyState.CLOSED {
return ReadyState.CLOSED
}
/**
* Open connections to relays.
*/
readonly #conns: ConnState[] = []
/**
* Mapping of subscription IDs to corresponding filters.
*/
readonly #subscriptions: Map<SubscriptionId, Filters[]> = new Map()
/**
* Open a connection and start communicating with a relay. This method recreates all existing
* subscriptions on the new relay as well. If there is already an existing connection,
* this method will only update it with the new options, and an exception will be thrown
* if no options are specified.
*/
open(
url: URL | string,
opts?: { read?: boolean; write?: boolean; fetchInfo?: boolean }
): void {
const relayUrl = new URL(url)
// If the connection already exists, update the options.
const existingConn = this.#conns.find(
(c) => c.relay.url.toString() === relayUrl.toString()
)
if (existingConn !== undefined) {
if (opts === undefined) {
throw new NostrError(
`called connect with existing connection ${url}, but options were not specified`
)
}
if (opts.read !== undefined) {
existingConn.read = opts.read
}
if (opts.write !== undefined) {
existingConn.write = opts.write
}
return
}
// Fetch the relay info in parallel to opening the WebSocket connection.
const fetchInfo =
opts?.fetchInfo === false
? Promise.resolve({})
: fetchRelayInfo(relayUrl).catch((e) => {
this.#error(e)
return {}
})
// If there is no existing connection, open a new one.
const conn = new Conn({
url: relayUrl,
// Handle messages on this connection.
onMessage: (msg) => {
if (msg.kind === "event") {
this.emit(
"event",
{
event: parseEvent(msg.event),
subscriptionId: msg.subscriptionId,
},
this
)
} else if (msg.kind === "notice") {
this.emit("notice", msg.notice, this)
} else if (msg.kind === "ok") {
this.emit(
"ok",
{
eventId: msg.eventId,
relay: relayUrl,
ok: msg.ok,
message: msg.message,
},
this
)
} else if (msg.kind === "eose") {
this.emit("eose", msg.subscriptionId, this)
} else if (msg.kind === "auth") {
// TODO This is incomplete
} else {
this.#error(new NostrError(`invalid message ${JSON.stringify(msg)}`))
}
},
// Handle "open" events.
onOpen: async () => {
// Update the connection readyState.
const conn = this.#conns.find(
(c) => c.relay.url.toString() === relayUrl.toString()
)
if (conn === undefined) {
this.#error(
new NostrError(
`bug: expected connection to ${relayUrl.toString()} to be in the map`
)
)
} else {
if (conn.relay.readyState !== ReadyState.CONNECTING) {
this.#error(
new NostrError(
`bug: expected connection to ${relayUrl.toString()} to have readyState CONNECTING, got ${
conn.relay.readyState
}`
)
)
}
conn.relay = {
...conn.relay,
readyState: ReadyState.OPEN,
info: await fetchInfo,
}
}
// Forward the event to the user.
this.emit("open", relayUrl, this)
},
// Handle "close" events.
onClose: () => {
// Update the connection readyState.
const conn = this.#conns.find(
(c) => c.relay.url.toString() === relayUrl.toString()
)
if (conn === undefined) {
this.#error(
new NostrError(
`bug: expected connection to ${relayUrl.toString()} to be in the map`
)
)
} else {
conn.relay.readyState = ReadyState.CLOSED
}
// Forward the event to the user.
this.emit("close", relayUrl, this)
},
// TODO If there is no error handler, this will silently swallow the error. Maybe have an
// #onError method which re-throws if emit() returns false? This should at least make
// some noise.
// Forward errors on this connection.
onError: (err) => this.#error(err),
})
// Resend existing subscriptions to this connection.
for (const [key, filters] of this.#subscriptions.entries()) {
conn.send({
kind: "openSubscription",
id: key,
filters,
})
}
this.#conns.push({
relay: {
url: relayUrl,
readyState: ReadyState.CONNECTING,
},
conn,
auth: false,
read: opts?.read ?? true,
write: opts?.write ?? true,
})
}
/**
* Close connections to relays.
*
* @param url If specified, only close the connection to this relay. If the connection does
* not exist, an exception will be thrown. If this parameter is not specified, all connections
* will be closed.
*/
close(url?: URL | string): void {
if (url === undefined) {
for (const { conn } of this.#conns.values()) {
conn.close()
}
return
}
const relayUrl = new URL(url)
const c = this.#conns.find(
(c) => c.relay.url.toString() === relayUrl.toString()
)
if (c === undefined) {
throw new NostrError(`connection to ${url} doesn't exist`)
}
c.conn.close()
}
/**
* Check if a subscription exists.
*/
subscribed(subscriptionId: SubscriptionId): boolean {
return this.#subscriptions.has(subscriptionId.toString())
}
/**
* Create a new subscription. If the subscription already exists, it will be overwritten (as per NIP-01).
*
* @param filters The filters to apply to this message. If any filter passes, the message is let through.
* @param subscriptionId An optional subscription ID, otherwise a random subscription ID will be used.
* @returns The subscription ID.
*/
subscribe(
filters: Filters[],
subscriptionId: SubscriptionId = randomSubscriptionId()
): SubscriptionId {
this.#subscriptions.set(subscriptionId, filters)
for (const { conn, read } of this.#conns.values()) {
if (!read) {
continue
}
conn.send({
kind: "openSubscription",
id: subscriptionId,
filters,
})
}
return subscriptionId
}
/**
* Remove a subscription. If the subscription does not exist, an exception is thrown.
*
* TODO Reference subscribed()
*/
unsubscribe(subscriptionId: SubscriptionId): void {
if (!this.#subscriptions.delete(subscriptionId)) {
throw new NostrError(`subscription ${subscriptionId} does not exist`)
}
for (const { conn, read } of this.#conns.values()) {
if (!read) {
continue
}
conn.send({
kind: "closeSubscription",
id: subscriptionId,
})
}
}
/**
* Publish an event.
*/
publish(event: RawEvent): void {
for (const { conn, write } of this.#conns.values()) {
if (!write) {
continue
}
conn.send({
kind: "event",
event,
})
}
}
/**
* Get the relays which this client has tried to open connections to.
*/
get relays(): Relay[] {
return this.#conns.map(({ relay }) => {
if (relay.readyState === ReadyState.CONNECTING) {
return { ...relay }
} else {
const info =
relay.info === undefined
? undefined
: // Deep copy of the info.
JSON.parse(JSON.stringify(relay.info))
return { ...relay, info }
}
})
}
#error(e: unknown) {
if (!this.emit("error", e, this)) {
throw e
}
}
}
interface ConnState {
relay: Relay
conn: Conn
/**
* Has this connection been authenticated via NIP-44 AUTH?
*/
auth: boolean
/**
* Should this connection be used for receiving events?
*/
read: boolean
/**
* Should this connection be used for publishing events?
*/
write: boolean
}
/**
* A string uniquely identifying a client subscription.
*/
export type SubscriptionId = string
function randomSubscriptionId(): SubscriptionId {
return utils.bytesToHex(globalThis.crypto.getRandomValues(new Uint8Array(32)))
}