Core Spotlight & NSUserActivity Reference

Overview

Comprehensive guide to Core Spotlight framework and NSUserActivity for making app content discoverable in Spotlight search, enabling Siri predictions, and supporting Handoff. Core Spotlight directly indexes app content while NSUserActivity captures user engagement for prediction.

Key distinction Core Spotlight = indexing all app content; NSUserActivity = marking current user activity for prediction/handoff.

When to Use This Skill

Use this skill when:

• Indexing app content (documents, notes, orders, messages) for Spotlight
• Using NSUserActivity for Handoff or Siri predictions
• Choosing between CSSearchableItem, IndexedEntity, and NSUserActivity
• Implementing activity continuation from Spotlight results
• Batch indexing for performance
• Deleting indexed content
• Debugging Spotlight search not finding app content
• Integrating NSUserActivity with App Intents (appEntityIdentifier)

Do NOT use this skill for:

• App Shortcuts implementation (use app-shortcuts-ref)
• App Intents basics (use app-intents-ref)
• Overall discoverability strategy (use app-discoverability)

Related Skills

• app-intents-ref — App Intents framework including IndexedEntity
• app-discoverability — Strategic guide for making apps discoverable
• app-shortcuts-ref — App Shortcuts for instant availability

When to Use Each API

Apple guidance Use NSUserActivity for user-initiated activities (screens currently visible), not as a general indexing mechanism. For comprehensive content indexing, use Core Spotlight's CSSearchableItem.

Core Spotlight (CSSearchableItem)

Creating Searchable Items

import CoreSpotlight
import UniformTypeIdentifiers

func indexOrder(_ order: Order) {
    // 1. Create attribute set with metadata
    let attributes = CSSearchableItemAttributeSet(contentType: .item)
    attributes.title = order.coffeeName
    attributes.contentDescription = "Ordered on \(order.date.formatted())"
    attributes.keywords = ["coffee", "order", order.coffeeName.lowercased()]
    attributes.thumbnailData = order.imageData

    // Optional: Add location
    attributes.latitude = order.location.coordinate.latitude
    attributes.longitude = order.location.coordinate.longitude

    // Optional: Add rating
    attributes.rating = NSNumber(value: order.rating)

    // 2. Create searchable item
    let item = CSSearchableItem(
        uniqueIdentifier: order.id.uuidString,        // Stable ID
        domainIdentifier: "orders",                   // Grouping
        attributeSet: attributes
    )

    // Optional: Set expiration
    item.expirationDate = Date().addingTimeInterval(60 * 60 * 24 * 365)  // 1 year

    // 3. Index the item
    CSSearchableIndex.default().indexSearchableItems([item]) { error in
        if let error = error {
            print("Indexing error: \(error.localizedDescription)")
        }
    }
}

Key Properties

uniqueIdentifier

Purpose Stable, persistent ID unique to this item within your app.

uniqueIdentifier: order.id.uuidString

Requirements:

• Must be stable (same item = same identifier)
• Used for updates and deletion
• Scoped to your app

domainIdentifier

Purpose Groups related items for bulk operations.

domainIdentifier: "orders"

Use cases:

• Delete all items in a domain
• Organize by type (orders, documents, messages)
• Batch operations

Pattern:

// Index with domains
item1.domainIdentifier = "orders"
item2.domainIdentifier = "documents"

// Delete entire domain
CSSearchableIndex.default().deleteSearchableItems(
    withDomainIdentifiers: ["orders"]
) { error in }

CSSearchableItemAttributeSet

Metadata describing the searchable content.

let attributes = CSSearchableItemAttributeSet(contentType: .item)

// Required
attributes.title = "Order #1234"
attributes.displayName = "Coffee Order"

// Highly recommended
attributes.contentDescription = "Medium latte with oat milk"
attributes.keywords = ["coffee", "latte", "order"]
attributes.thumbnailData = imageData

// Optional but valuable
attributes.contentCreationDate = Date()
attributes.contentModificationDate = Date()
attributes.rating = NSNumber(value: 5)
attributes.comment = "My favorite order"

Common Attributes

Document-Specific Attributes

// For document types
attributes.contentType = UTType.pdf
attributes.author = "John Doe"
attributes.pageCount = 10
attributes.fileSize = 1024000
attributes.path = "/path/to/document.pdf"

Message-Specific Attributes

// For messages
attributes.recipients = ["[email protected]"]
attributes.recipientNames = ["Jane Doe"]
attributes.authorNames = ["John Doe"]
attributes.subject = "Meeting notes"

Batch Indexing for Performance

❌ DON'T: Index items one at a time

// Bad: 100 index operations
for order in orders {
    CSSearchableIndex.default().indexSearchableItems([order.asSearchableItem()]) { _ in }
}

✅ DO: Batch index operations

// Good: 1 index operation
let items = orders.map { $0.asSearchableItem() }

CSSearchableIndex.default().indexSearchableItems(items) { error in
    if let error = error {
        print("Batch indexing error: \(error)")
    } else {
        print("Indexed \(items.count) items")
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