Indexing content using Core Spotlight

The Apple documentation on CoreSpotlight breaks down the process of creating and adding items to a searchable index:

Create a CSSearchableItemAttributeSet object and specify properties that describe the item you want to index.

Create a CSSearchableItem object to represent the item. A CSSearchableItem object has a unique identifier that lets you refer to it later.

If needed, specify a domain identifier so that you can gather multiple items together and manage them as a group.

Associate the attribute set with the searchable item.

Add the searchable item to the index.

Here's a quick example I that shows how to index a simple Note class:

class Note {
    var title: String
    var description: String
    var image: UIImage?

    init(title: String, description: String) {
        self.title = title
        self.description = description
    }
}

Then in some other function, create your notes, create a CSSearchableItemAttributeSet for each note, create a unique CSSearchableItem from the attribute set, and index the collection of searchable items:

import CoreSpotlight
import MobileCoreServices

// ...

// Build your Notes data source to index
var notes = [Note]()
notes.append(Note(title: "Grocery List", description: "Buy milk, eggs"))
notes.append(Note(title: "Reminder", description: "Soccer practice at 3"))
let parkingReminder = Note(title: "Reminder", description: "Soccer practice at 3")
parkingReminder.image = UIImage(named: "parkingReminder")
notes.append(parkingReminder)

// The array of items that will be indexed by CoreSpotlight
var searchableItems = [CSSearchableItem]()

for note in notes {
    // create an attribute set of type Text, since our reminders are text
    let searchableItemAttributeSet = CSSearchableItemAttributeSet(itemContentType: kUTTypeText as String)

    // If we have an image, add it to the attribute set
    if let image = note.image {
        searchableItemAttributeSet.thumbnailData = UIImagePNGRepresentation(image)
        // you can also use thumbnailURL if your image is coming from a server or the bundle
//        searchableItemAttributeSet.thumbnailURL = NSBundle.mainBundle().URLForResource("image", withExtension: "jpg")
    }

    // set the properties on the item to index
    searchableItemAttributeSet.title = note.title
    searchableItemAttributeSet.contentDescription = note.description

    // Build your keywords
    // In this case, I'm tokenizing the title of the note by a space and using the values returned as the keywords
    searchableItemAttributeSet.keywords = note.title.componentsSeparatedByString(" ")

    // create the searchable item
    let searchableItem = CSSearchableItem(uniqueIdentifier: "com.mygreatapp.notes" + ".\(note.title)", domainIdentifier: "notes", attributeSet: searchableItemAttributeSet)
}

// Add our array of searchable items to the Spotlight index
CSSearchableIndex.defaultSearchableIndex().indexSearchableItems(searchableItems) { (error) in
    if let error = error {
        // handle failure
        print(error)
    }
}

This example has been adapted from AppCoda's How To Use Core Spotlight Framework in iOS 9 guide.

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