feat: implement Relay.

README.md

@@ -23,7 +23,7 @@ npm install nostrain
 
 ## Usage
 
-- See [examples](https://github.com/susumuota/nostrain/tree/main/examples).
+- See [examples](https://github.com/susumuota/nostrain/tree/main/examples) directory.
 
 ### Generating a private key and a public key
 
@@ -39,7 +39,14 @@ console.log({ sk, pk });
 ### Creating, signing and verifying events
 
 ```javascript
-import { validateEvent, verifySignature, signEvent, getEventHash, generatePrivateKey, getPublicKey } from 'nostrain';
+import {
+  validateEvent,
+  verifySignature,
+  signEvent,
+  getEventHash,
+  generatePrivateKey,
+  getPublicKey,
+} from 'nostrain';
 
 const privateKey = generatePrivateKey();
 
@@ -63,7 +70,83 @@ console.log({ event, validateOk, verifyOk });
 
 ### Interacting with a relay
 
-TODO: work in progress
+```javascript
+import crypto from 'node:crypto';
+globalThis.crypto = crypto;
+
+import 'websocket-polyfill';
+import { relayInit, generatePrivateKey, getPublicKey, getEventHash, signEvent } from 'nostrain';
+
+const relay = relayInit('wss://relay.damus.io');
+
+relay.on('connect', () => {
+  console.log(`connected to ${relay.url}`);
+});
+relay.on('error', () => {
+  console.log(`failed to connect to ${relay.url}`);
+});
+
+await relay.connect();
+
+{
+  // let's query for an event that exists
+  const sub = relay.sub([{ ids: ['d7dd5eb3ab747e16f8d0212d53032ea2a7cadef53837e5a6c66d42849fcb9027'] }]);
+
+  sub.on('event', event => {
+    console.log('we got the event we wanted:', event);
+  });
+  sub.on('eose', () => {
+    sub.unsub();
+  });
+}
+
+{
+  // let's publish a new event while simultaneously monitoring the relay for it
+  const sk = generatePrivateKey();
+  const pk = getPublicKey(sk);
+
+  const sub = relay.sub([{ kinds: [1], authors: [pk] }]);
+
+  sub.on('event', event => {
+    console.log('got event:', event);
+  });
+
+  const event = {
+    kind: 1,
+    pubkey: pk,
+    created_at: Math.floor(Date.now() / 1000),
+    tags: [],
+    content: 'hello world',
+  };
+  event.id = getEventHash(event);
+  event.sig = signEvent(event, sk);
+
+  const pub = relay.publish(event);
+  pub.on('ok', () => {
+    console.log(`${relay.url} has accepted our event`);
+  });
+  pub.on('failed', reason => {
+    console.log(`failed to publish to ${relay.url}: ${reason}`);
+  });
+}
+
+{
+  // let's query for events by list and get
+  const events = await relay.list([{ kinds: [0, 1] }]);
+  console.log(events.length);
+
+  const event = await relay.get({ ids: ['d7dd5eb3ab747e16f8d0212d53032ea2a7cadef53837e5a6c66d42849fcb9027'] });
+  console.log({ event });
+}
+
+relay.close();
+```
+
+To use this on Node.js you first must install `websocket-polyfill` and import it:
+
+```javascript
+import 'websocket-polyfill'
+```
 
 ### Interacting with multiple relays
 
@@ -175,7 +258,8 @@ console.log({ tags: event.tags });
 // finally any receiver of this event can check for the presence of a valid delegation tag
 const delegator = nip26.getDelegator(event);
 
-console.log({ delegator, pk1, success: delegator === pk1 }); // will be null if there is no delegation tag or if it is invalid
+// will be null if there is no delegation tag or if it is invalid
+console.log({ delegator, pk1, success: delegator === pk1 });
 ```
 
 ## Development

examples/delegation.js

@@ -37,4 +37,5 @@ console.log({ tags: event.tags });
 // finally any receiver of this event can check for the presence of a valid delegation tag
 const delegator = nip26.getDelegator(event);
 
-console.log({ delegator, pk1, success: delegator === pk1 }); // will be null if there is no delegation tag or if it is invalid
+// will be null if there is no delegation tag or if it is invalid
+console.log({ delegator, pk1, success: delegator === pk1 });

examples/relay.js

@@ -0,0 +1,74 @@
+// SPDX-FileCopyrightText: 2023 Susumu OTA <1632335+susumuota@users.noreply.github.com>
+// SPDX-License-Identifier: MIT
+
+// node examples/relay.js
+
+import crypto from 'node:crypto';
+globalThis.crypto = crypto;
+
+import 'websocket-polyfill';
+import { relayInit, generatePrivateKey, getPublicKey, getEventHash, signEvent } from 'nostrain';
+
+const relay = relayInit('wss://relay.damus.io');
+
+relay.on('connect', () => {
+  console.log(`connected to ${relay.url}`);
+});
+relay.on('error', () => {
+  console.log(`failed to connect to ${relay.url}`);
+});
+
+await relay.connect();
+
+{
+  // let's query for an event that exists
+  const sub = relay.sub([{ ids: ['d7dd5eb3ab747e16f8d0212d53032ea2a7cadef53837e5a6c66d42849fcb9027'] }]);
+
+  sub.on('event', event => {
+    console.log('we got the event we wanted:', event);
+  });
+  sub.on('eose', () => {
+    sub.unsub();
+  });
+}
+
+{
+  // let's publish a new event while simultaneously monitoring the relay for it
+  const sk = generatePrivateKey();
+  const pk = getPublicKey(sk);
+
+  const sub = relay.sub([{ kinds: [1], authors: [pk] }]);
+
+  sub.on('event', event => {
+    console.log('got event:', event);
+  });
+
+  const event = {
+    kind: 1,
+    pubkey: pk,
+    created_at: Math.floor(Date.now() / 1000),
+    tags: [],
+    content: 'hello world',
+  };
+  event.id = getEventHash(event);
+  event.sig = signEvent(event, sk);
+
+  const pub = relay.publish(event);
+  pub.on('ok', () => {
+    console.log(`${relay.url} has accepted our event`);
+  });
+  pub.on('failed', reason => {
+    console.log(`failed to publish to ${relay.url}: ${reason}`);
+  });
+}
+
+{
+  // let's query for events by list and get
+  const events = await relay.list([{ kinds: [0, 1] }]);
+  console.log(events.length);
+
+  const event = await relay.get({ ids: ['d7dd5eb3ab747e16f8d0212d53032ea2a7cadef53837e5a6c66d42849fcb9027'] });
+  console.log({ event });
+}
+
+relay.close();