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Relay Pool ​

The RelayPool class in applesauce-relay provides a powerful way to manage multiple relay connections, allowing you to interact with multiple relays as if they were a single entity.

Features ​

  • Connect to multiple relays
  • Create and manage groups of relays
  • Send requests and events to multiple relays simultaneously
  • Maintain a blacklist of relays to avoid

Relay Management ​

The RelayPool provides methods to create and manage relay connections:

typescript
// Get or create a relay connection
const relay = pool.relay("wss://relay.example.com");

// Create a group of relays
const group = pool.group(["wss://relay1.example.com", "wss://relay2.example.com"]);

Making Requests ​

The RelayPool provides several methods to interact with relays. These methods mirror those found in the Relay class, allowing you to use familiar patterns while working with multiple relays simultaneously.

REQ Method ​

The req method sends a subscription request to multiple relays:

typescript
// Send a REQ to multiple relays
pool
  .req(relays, {
    kinds: [1],
    limit: 10,
  })
  .subscribe({
    next: (response) => {
      if (response === "EOSE") {
        console.log("End of stored events from all relays");
      } else {
        console.log("Event from relay:", response.from);
        console.log("Event content:", response.content);
      }
    },
    error: (error) => {
      console.error("Subscription error:", error);
    },
  });

EVENT Method ​

The event method publishes an event to multiple relays and returns an observable of the responses from each relay.

typescript
const event = {
  kind: 1,
  content: "Hello from RelayPool!",
  created_at: Math.floor(Date.now() / 1000),
  tags: [],
  // ... other required fields
};

pool.event(relays, event).subscribe({
  next: (response) => {
    console.log(`Published to ${response.from}:`, response.ok);
    if (!response.ok) console.log(`Error message: ${response.message}`);
  },
  complete: () => {
    console.log("Publishing complete");
  },
});

Publish Method ​

The publish method is similar to event but includes automatic retries:

typescript
// Publish with retries (defaults to 3 retries)
pool.publish(relays, event, { retries: 5 }).subscribe({
  next: (response) => {
    console.log(`Published to ${response.from}:`, response.ok);
  },
  complete: () => {
    console.log("Publishing complete (with retries)");
  },
});

Request Method ​

The request method allows you to make one-off requests with automatic retries:

typescript
// Request with automatic retries
pool
  .request(
    relays,
    {
      kinds: [1],
      authors: ["pubkey1", "pubkey2"],
      limit: 50,
    },
    {
      retries: 2,
      timeout: 5000, // 5 seconds
    },
  )
  .subscribe({
    next: (event) => console.log("Received event:", event.id),
    complete: () => console.log("Request complete"),
  });

Subscription Method ​

The subscription method creates persistent subscriptions that automatically reconnect:

typescript
// Create persistent subscription
const subscription = pool
  .subscription(
    relays,
    {
      kinds: [1, 7],
      "#t": ["nostr"],
    },
    {
      id: "custom-sub-id", // optional custom subscription ID
      retries: Infinity, // retry forever
    },
  )
  .subscribe({
    next: (response) => {
      if (response === "EOSE") {
        console.log("End of stored events");
      } else {
        console.log("Subscription update:", response);
      }
    },
  });

// Later, you can unsubscribe
subscription.unsubscribe();

All of these methods accept the same parameters as their counterparts in the Relay class, making it easy to transition between working with individual relays and relay pools.

Relay Groups ​

The RelayGroup class is used internally by RelayPool to manage collections of relays. You can access relay groups directly through the pool:

typescript
// Create a group of relays
const group = pool.group(["wss://relay1.example.com", "wss://relay2.example.com"]);

// Make requests to the group
group.req({ kinds: [1] }).subscribe((response) => console.log(response));

// Send events to the group
group.event(event).subscribe((response) => console.log(response));

// Use other group methods
group.publish(event).subscribe((response) => console.log(response));
group.request({ kinds: [1] }).subscribe((event) => console.log(event));
group.subscription({ kinds: [1] }).subscribe((response) => console.log(response));

The RelayGroup intelligently merges responses from multiple relays, emitting EOSE only when all relays have sent their EOSE signals.

Observable Properties ​

The RelayPool provides observables for tracking relays and groups:

typescript
// Subscribe to changes in the relays map
pool.relays$.subscribe((relaysMap) => {
  console.log("Relays updated:", Array.from(relaysMap.keys()));
});

// Subscribe to changes in the relay groups map
pool.groups$.subscribe((groupsMap) => {
  console.log("Groups updated:", Array.from(groupsMap.keys()));
});