discoverHubs

Discovers WebSub hubs from a feed or webpage.

Signature

function discoverHubs(
  input: DiscoverInput,
  options?: DiscoverHubsOptions,
): Promise<Array<HubResult>>

Parameters

input

The URL to discover hubs from. Can be a string or an object:

// String - URL to fetch and scan
discoverHubs('https://example.com/feed.xml')

// Object - provide existing content/headers
discoverHubs({
  url: 'https://example.com/feed.xml',
  content: feedContent,
  headers: responseHeaders,
})

options

Property	Type	Default	Description
methods	DiscoverHubsMethodsConfig	all	Methods to use
fetchFn	DiscoverFetchFn	native fetch	Custom fetch function

methods

Array of discovery methods to use:

type DiscoverHubsMethodsConfig = Array<'headers' | 'html' | 'feed'>

• headers — Parse HTTP Link headers for rel="hub".
• feed — Extract hub links from feed content (Atom, RSS, JSON Feed).
• html — Scan for <link rel="hub"> elements.

Return Value

Returns a promise that resolves to an array of hub results:

type HubResult = {
  hub: string   // Hub URL to subscribe to
  topic: string // Feed URL the hub serves updates for
}

Example result:

{
  hub: 'https://pubsubhubbub.appspot.com',
  topic: 'https://example.com/feed.xml',
}

Examples

Basic Usage

import { discoverHubs } from 'feedscout'

const hubs = await discoverHubs('https://example.com/feed.xml')

With Specific Methods

const hubs = await discoverHubs('https://example.com/feed.xml', {
  methods: ['headers', 'feed'],
})

With Existing Content

const response = await fetch('https://example.com/feed.xml')
const content = await response.text()

const hubs = await discoverHubs(
  {
    url: 'https://example.com/feed.xml',
    content: await response.text(),
    headers: response.headers,
  },
  {
    methods: ['headers', 'feed'],
  },
)

With Custom HTTP Client

import type { DiscoverFetchFn } from 'feedscout'

const myCustomFetch: DiscoverFetchFn = async (url, options) => {
  // Handle the request and return response here.
}

const hubs = await discoverHubs('https://example.com/feed.xml', {
  methods: ['headers', 'feed'],
  fetchFn: myCustomFetch,
})

See Customize Data Fetching for examples with Axios, Got, Ky, and more.