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dpearson2699/swift-ios-skills

Agent skills for iOS, iPadOS, Swift, SwiftUI, and modern Apple framework development.

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SKILL.mdskills/contacts-framework/

name:
contacts-framework
description:
Read, create, update, and pick contacts using the Contacts and ContactsUI frameworks. Use when fetching contact data, saving new contacts, wrapping CNContactPickerViewController in SwiftUI, handling contact permissions, or working with CNContactStore fetch and save requests.

Contacts Framework

Fetch, create, update, and pick contacts from the user's Contacts database using CNContactStore, CNSaveRequest, and CNContactPickerViewController. Targets Swift 6.3 / iOS 26+.

Contents

  • Setup
  • Authorization
  • Fetching Contacts
  • Key Descriptors
  • Creating and Updating Contacts
  • Contact Picker
  • Observing Changes
  • Common Mistakes
  • Review Checklist
  • References

Setup

Project Configuration

  1. Add NSContactsUsageDescription to Info.plist explaining why the app accesses contacts. The app crashes if it uses contact data APIs without this key.
  2. No additional capability or entitlement is required for ordinary Contacts access.
  3. Add com.apple.developer.contacts.notes only when reading or writing CNContactNoteKey / CNContact.note; this entitlement requires Apple approval before public distribution.

Imports

@preconcurrency import Contacts  // CNContactStore, CNSaveRequest, CNContact
import ContactsUI                // CNContactPickerViewController

Authorization

Request access before fetching or saving contacts. The picker (CNContactPickerViewController) does not require authorization -- the system grants access only to the contacts the user selects.

let store = CNContactStore()

func requestAccess() async throws -> Bool {
    return try await store.requestAccess(for: .contacts)
}

// Check current status without prompting
func checkStatus() -> CNAuthorizationStatus {
    CNContactStore.authorizationStatus(for: .contacts)
}

Authorization States

StatusMeaning
.notDeterminedUser has not been prompted yet
.authorizedFull read/write access granted
.deniedUser denied access; direct to Settings
.restrictedParental controls or MDM restrict access
.limitediOS 18+: user granted access to selected contacts only

Treat both .authorized and .limited as usable Contacts API states. With .limited, fetch, edit, and delete operations only apply to contacts the user granted or the app created. Use ContactAccessButton or contactAccessPicker(isPresented:completionHandler:) to let users add contacts to the app's limited-access set.

Fetching Contacts

Use unifiedContacts(matching:keysToFetch:) for predicate-based queries. Use enumerateContacts(with:usingBlock:) for batch enumeration of all contacts. For large cached address books, first fetch identifiers, then fetch detailed contacts in batches by identifier.

Fetch by Name

func fetchContacts(named name: String) throws -> [CNContact] {
    let predicate = CNContact.predicateForContacts(matchingName: name)
    let keys: [CNKeyDescriptor] = [
        CNContactGivenNameKey as CNKeyDescriptor,
        CNContactFamilyNameKey as CNKeyDescriptor,
        CNContactPhoneNumbersKey as CNKeyDescriptor
    ]
    return try store.unifiedContacts(matching: predicate, keysToFetch: keys)
}

Fetch by Identifier

func fetchContact(identifier: String) throws -> CNContact {
    let keys: [CNKeyDescriptor] = [
        CNContactGivenNameKey as CNKeyDescriptor,
        CNContactFamilyNameKey as CNKeyDescriptor,
        CNContactEmailAddressesKey as CNKeyDescriptor
    ]
    return try store.unifiedContact(withIdentifier: identifier, keysToFetch: keys)
}

Enumerate All Contacts

Perform I/O-heavy enumeration off the main thread.

func fetchAllContacts() throws -> [CNContact] {
    let keys: [CNKeyDescriptor] = [
        CNContactGivenNameKey as CNKeyDescriptor,
        CNContactFamilyNameKey as CNKeyDescriptor
    ]
    let request = CNContactFetchRequest(keysToFetch: keys)
    request.sortOrder = .givenName

    var contacts: [CNContact] = []
    try store.enumerateContacts(with: request) { contact, _ in
        contacts.append(contact)
    }
    return contacts
}

Key Descriptors

Only fetch the properties you need. Accessing an unfetched property throws CNContactPropertyNotFetchedException.

Common Keys

KeyProperty
CNContactGivenNameKeyFirst name
CNContactFamilyNameKeyLast name
CNContactPhoneNumbersKeyPhone numbers array
CNContactEmailAddressesKeyEmail addresses array
CNContactPostalAddressesKeyMailing addresses array
CNContactImageDataKeyFull-resolution contact photo
CNContactThumbnailImageDataKeyThumbnail contact photo
CNContactBirthdayKeyBirthday date components
CNContactOrganizationNameKeyCompany name

Composite Key Descriptors

Use CNContactFormatter.descriptorForRequiredKeys(for:) to fetch all keys needed for formatting a contact's name.

let nameKeys = CNContactFormatter.descriptorForRequiredKeys(for: .fullName)
let keys: [CNKeyDescriptor] = [nameKeys, CNContactPhoneNumbersKey as CNKeyDescriptor]

Creating and Updating Contacts

Use CNMutableContact to build new contacts and CNSaveRequest to persist changes.

Creating a New Contact

func createContact(givenName: String, familyName: String, phone: String) throws {
    let contact = CNMutableContact()
    contact.givenName = givenName
    contact.familyName = familyName
    contact.phoneNumbers = [
        CNLabeledValue(
            label: CNLabelPhoneNumberMobile,
            value: CNPhoneNumber(stringValue: phone)
        )
    ]

    let saveRequest = CNSaveRequest()
    saveRequest.add(contact, toContainerWithIdentifier: nil) // nil = default container
    try store.execute(saveRequest)
}

Updating an Existing Contact

You must fetch the contact with the properties you intend to modify, create a mutable copy, change the properties, then save.

func updateContactEmail(identifier: String, email: String) throws {
    let keys: [CNKeyDescriptor] = [
        CNContactEmailAddressesKey as CNKeyDescriptor
    ]
    let contact = try store.unifiedContact(withIdentifier: identifier, keysToFetch: keys)
    guard let mutable = contact.mutableCopy() as? CNMutableContact else { return }

    mutable.emailAddresses.append(
        CNLabeledValue(label: CNLabelWork, value: email as NSString)
    )

    let saveRequest = CNSaveRequest()
    saveRequest.update(mutable)
    try store.execute(saveRequest)
}

Deleting a Contact

func deleteContact(identifier: String) throws {
    let keys: [CNKeyDescriptor] = [CNContactIdentifierKey as CNKeyDescriptor]
    let contact = try store.unifiedContact(withIdentifier: identifier, keysToFetch: keys)
    guard let mutable = contact.mutableCopy() as? CNMutableContact else { return }

    let saveRequest = CNSaveRequest()
    saveRequest.delete(mutable)
    try store.execute(saveRequest)
}

Contact Picker

CNContactPickerViewController lets users pick contacts without granting full Contacts access. The app receives only the selected contact data.

SwiftUI Wrapper

import SwiftUI
import ContactsUI

struct ContactPicker: UIViewControllerRepresentable {
    @Binding var selectedContact: CNContact?

    func makeUIViewController(context: Context) -> CNContactPickerViewController {
        let picker = CNContactPickerViewController()
        picker.delegate = context.coordinator
        return picker
    }

    func updateUIViewController(_ uiViewController: CNContactPickerViewController, context: Context) {}

    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }

    final class Coordinator: NSObject, CNContactPickerDelegate {
        let parent: ContactPicker

        init(_ parent: ContactPicker) {
            self.parent = parent
        }

        func contactPicker(_ picker: CNContactPickerViewController, didSelect contact: CNContact) {
            parent.selectedContact = contact
        }

        func contactPickerDidCancel(_ picker: CNContactPickerViewController) {
            parent.selectedContact = nil
        }
    }
}

Using the Picker

struct ContactSelectionView: View {
    @State private var selectedContact: CNContact?
    @State private var showPicker = false

    var body: some View {
        VStack {
            if let contact = selectedContact {
                Text("\(contact.givenName) \(contact.familyName)")
            }
            Button("Select Contact") {
                showPicker = true
            }
        }
        .sheet(isPresented: $showPicker) {
            ContactPicker(selectedContact: $selectedContact)
        }
    }
}

Filtering the Picker

Use predicates to control which contacts appear and what the user can select.

let picker = CNContactPickerViewController()
// Only show contacts that have an email address
picker.predicateForEnablingContact = NSPredicate(format: "emailAddresses.@count > 0")
// Selecting a contact returns it directly (no detail card)
picker.predicateForSelectionOfContact = NSPredicate(value: true)

Observing Changes

Listen for external contact database changes to refresh cached data.

func observeContactChanges() {
    NotificationCenter.default.addObserver(
        forName: .CNContactStoreDidChange,
        object: nil,
        queue: .main
    ) { _ in
        // Refetch contacts -- cached CNContact objects are stale
        refreshContacts()
    }
}

Common Mistakes

DON'T: Fetch all keys when you only need a name

Over-fetching wastes memory and slows queries, especially for contacts with large photos.

// WRONG: Fetches far more than the UI displays, including full-resolution photos
let keys: [CNKeyDescriptor] = [
    CNContactFormatter.descriptorForRequiredKeys(for: .fullName),
    CNContactImageDataKey as CNKeyDescriptor,
    CNContactPhoneNumbersKey as CNKeyDescriptor,
    CNContactEmailAddressesKey as CNKeyDescriptor,
    CNContactPostalAddressesKey as CNKeyDescriptor,
    CNContactBirthdayKey as CNKeyDescriptor
]

// CORRECT: Fetch only what you display
let keys: [CNKeyDescriptor] = [
    CNContactGivenNameKey as CNKeyDescriptor,
    CNContactFamilyNameKey as CNKeyDescriptor
]

DON'T: Access unfetched properties

Accessing a property that was not in keysToFetch throws CNContactPropertyNotFetchedException at runtime.

// WRONG: Only fetched name keys, now accessing phone
let keys: [CNKeyDescriptor] = [CNContactGivenNameKey as CNKeyDescriptor]
let contact = try store.unifiedContact(withIdentifier: id, keysToFetch: keys)
let phone = contact.phoneNumbers.first // CRASH

// CORRECT: Include the key you need
let keys: [CNKeyDescriptor] = [
    CNContactGivenNameKey as CNKeyDescriptor,
    CNContactPhoneNumbersKey as CNKeyDescriptor
]

DON'T: Mutate a CNContact directly

CNContact is immutable. You must call mutableCopy() to get a CNMutableContact.

// WRONG: CNContact has no setter
let contact = try store.unifiedContact(withIdentifier: id, keysToFetch: keys)
contact.givenName = "New Name" // Compile error

// CORRECT: Create mutable copy
guard let mutable = contact.mutableCopy() as? CNMutableContact else { return }
mutable.givenName = "New Name"

DON'T: Skip authorization and assume access

Do not let fetch or save calls be the first place the user sees authorization. If status is .notDetermined, request access; if access was denied, contact operations fail with an authorization error.

// WRONG: Jump straight to fetch
let contacts = try store.unifiedContacts(matching: predicate, keysToFetch: keys)

// CORRECT: Check or request access first
let granted = try await store.requestAccess(for: .contacts)
guard granted else { return }
let contacts = try store.unifiedContacts(matching: predicate, keysToFetch: keys)

DON'T: Run heavy fetches on the main thread

enumerateContacts performs I/O. Running it on the main thread blocks the UI. When strict concurrency checks complain about CNContact crossing task or actor boundaries, use @preconcurrency import Contacts in that file or map contacts into Sendable view models before returning them.

// WRONG: Main thread enumeration
func loadContacts() {
    try store.enumerateContacts(with: request) { contact, _ in ... }
}

// CORRECT: Run on a background thread
func loadContacts() async throws -> [CNContact] {
    try await Task.detached {
        var results: [CNContact] = []
        try store.enumerateContacts(with: request) { contact, _ in
            results.append(contact)
        }
        return results
    }.value
}

Review Checklist

  • NSContactsUsageDescription added to Info.plist
  • requestAccess(for: .contacts) called before fetch or save operations
  • .limited treated as usable access with selected-contact caveats
  • ContactAccessButton or contactAccessPicker offered when users need to expand limited access
  • Authorization denial handled gracefully (guide user to Settings)
  • Only needed CNKeyDescriptor keys included in fetch requests
  • CNContactFormatter.descriptorForRequiredKeys(for:) used when formatting names
  • Mutable copy created via mutableCopy() before modifying contacts
  • CNSaveRequest used for all create/update/delete operations
  • Heavy fetches (enumerateContacts) run off the main thread
  • CNContactStoreDidChange observed to refresh cached contacts
  • CNContactPickerViewController used when full Contacts access is unnecessary
  • Picker predicates set before presenting the picker view controller
  • Single CNContactStore instance reused across the app

References

  • Extended patterns (multi-select picker, vCard export, search optimization): references/contacts-patterns.md
  • Contacts framework
  • CNContactStore
  • CNContactFetchRequest
  • CNSaveRequest
  • CNMutableContact
  • CNContactPickerViewController
  • CNContactPickerDelegate
  • Accessing the contact store
  • NSContactsUsageDescription
  • ContactAccessButton
  • contactAccessPicker(isPresented:completionHandler:)
  • Contact Keys

skills

contacts-framework

SKILL.md

README.md

tile.json