Feed Compiler

The FeedCompiler class transforms feed definitions into optimized RequestItem[] arrays containing filters and relay selections for efficient event fetching.

Types

export type FeedCompilerOptions = {
  signer?: ISigner
  signal?: AbortSignal
  context?: AdapterContext
  getPubkeysForScope: (scope: Scope) => string[]
  getPubkeysForWOTRange: (minWOT: number, maxWOT: number) => string[]
}

FeedCompiler Class

export class FeedCompiler {
  constructor(readonly options: FeedCompilerOptions)

  // Check if a feed can be compiled
  canCompile(feed: Feed): boolean

  // Compile a feed into request items
  async compile(feed: Feed): Promise<RequestItem[]>
}

Compilation Logic

Basic Feed Types

• ID feeds → {filters: [{ids: [...]}]}
• Kind feeds → {filters: [{kinds: [...]}]}
• Author feeds → {filters: [{authors: [...]}]}
• Tag feeds → {filters: [{[key]: [...values]}]}
• Address feeds → Converts to ID filters using getIdFilters()
• Relay feeds → {relays: [...urls]}
• Global feeds → {filters: [{}]}

Time-based Feeds

• CreatedAt feeds → Processes since/until with optional relative timestamps
• Scope feeds → Resolves to author filters using getPubkeysForScope()
• WOT feeds → Resolves to author filters using getPubkeysForWOTRange()
• Search feeds → {filters: [{search: "term"}]}

Complex Feed Types

• DVM feeds → Requests DVM responses and converts result tags to feeds
• List feeds → Fetches list events and converts their tags to feeds
• Label feeds → Fetches label events (kind 1985) and converts tags to feeds

Set Operations

• Union feeds → Merges all sub-feed results, optimizing by relay
• Intersection feeds → Finds overlapping filters and relays across sub-feeds

Usage

import { FeedCompiler, makeAuthorFeed, makeKindFeed } from '@welshman/feeds'

const compiler = new FeedCompiler({
  getPubkeysForScope: (scope) => [...], // Your scope resolution logic
  getPubkeysForWOTRange: (min, max) => [...], // Your WOT logic
  context: adapterContext,
  signal: abortSignal
})

// Compile a simple feed
const feed = makeAuthorFeed("pubkey1", "pubkey2")
const requests = await compiler.compile(feed)
// => [{filters: [{authors: ["pubkey1", "pubkey2"]}]}]

// Check if feed can be compiled
if (compiler.canCompile(feed)) {
  const requests = await compiler.compile(feed)
}