Easily access a read-only array of all the people in the contacts database for iOS. (Because Apple STILL hasn't made an ABAddressBook class for iOS like they did for MacOS.

AddressBook.h

#import <Foundation/Foundation.h>

extern NSString *addressBookErrorDomain;

typedef NS_ENUM(NSInteger, AddressBookError) {
	AddressBookErrorOK,
	AddressBookErrorNoAddressBook,
	AddressBookErrorNoAccess
};


extern NSString *AddressBookChangedNotification;

@interface AddressBook : NSObject

@property (nonatomic, copy, readonly) NSArray *people;

+ (void)performAction:(void (^)(AddressBook *addressBook, NSError *error))action;
@end

AddressBook.m

#import "AddressBook.h"

@import AddressBook;
#import "PersonRecord.h"


NSString *addressBookErrorDomain = @"com.hanekedesign.addressbookerror";

NSString *AddressBookChangedNotification = @"com.hanekedesign.addressbookchanged";

static void addressBookCallback(ABAddressBookRef addressBookRef, CFDictionaryRef info, void* context) {
	[[NSNotificationCenter defaultCenter] postNotificationName:AddressBookChangedNotification object:nil];
}

static ABAddressBookRef getAddressBookRef() {
	static ABAddressBookRef addressBookRef;
	static dispatch_once_t onceToken;
	dispatch_once(&onceToken, ^{
		CFErrorRef* error = NULL;
		addressBookRef = ABAddressBookCreateWithOptions(NULL, error);
		if (error) {
			addressBookRef = NULL;
		}
		else {
			ABAddressBookRegisterExternalChangeCallback(addressBookRef, &addressBookCallback, NULL);
		}
	});
	return addressBookRef;
}

@interface AddressBook ()

@property (nonatomic, assign) ABAddressBookRef addressBookRef;
@property (nonatomic, assign, readonly) BOOL isValid;
@end


@implementation AddressBook

+ (void)performAction:(void (^)(AddressBook *addressBook, NSError *error))action {
	AddressBook *addressBook = [[AddressBook alloc] init];
	if (addressBook.isValid) {
		ABAddressBookRequestAccessWithCompletion(addressBook.addressBookRef, ^(bool granted, CFErrorRef error) {
			if (granted) {
				action(addressBook, nil);
			}
			else {
				NSError *error = [NSError errorWithDomain:addressBookErrorDomain code:AddressBookErrorNoAccess userInfo:nil];
				action(nil, error);
			}
		});
	}
	else {
		NSError *error = [NSError errorWithDomain:addressBookErrorDomain code:AddressBookErrorNoAddressBook userInfo:nil];
		action(nil, error);
	}
}

- (instancetype)init {
	self = [super init];
	if (self) {
		self.addressBookRef = getAddressBookRef();
	}
	return self;
}

- (BOOL)isValid {
	return self.addressBookRef != NULL;
}

- (NSArray *)people {
	NSMutableArray * result = [[NSMutableArray alloc] init];
	NSArray *basePeople = CFBridgingRelease(ABAddressBookCopyArrayOfAllPeople(self.addressBookRef));
	for (int i = 0; i < basePeople.count; ++i) {
		ABRecordRef record = (__bridge ABRecordRef)(basePeople[i]);
		PersonRecord *personRecord = [[PersonRecord alloc] init];
		personRecord.compositeName = CFBridgingRelease(ABRecordCopyCompositeName(record)) ?: @"";
		personRecord.organization = CFBridgingRelease(ABRecordCopyValue(record, kABPersonOrganizationProperty)) ?: @"";
		personRecord.jobTitle = CFBridgingRelease(ABRecordCopyValue(record, kABPersonJobTitleProperty)) ?: @"";
		personRecord.emails = [self multiValuesFromRecord:record forProperty:kABPersonEmailProperty];
		personRecord.phones = [self multiValuesFromRecord:record forProperty:kABPersonPhoneProperty];
		[result addObject:personRecord];
	}
	return result;
}

- (NSArray *)multiValuesFromRecord:(ABRecordRef)record forProperty:(ABPropertyID)property {
	ABMultiValueRef baseValues = ABRecordCopyValue(record, property);
	NSMutableArray *values = [[NSMutableArray alloc] initWithCapacity:ABMultiValueGetCount(baseValues)];
	for (int i = 0; i < ABMultiValueGetCount(baseValues); ++i) {
		MultiValue *multiValue = [[MultiValue alloc] init];
		multiValue.label = CFBridgingRelease(ABMultiValueCopyLabelAtIndex(baseValues, i)) ?: @"";
		multiValue.value = CFBridgingRelease(ABMultiValueCopyValueAtIndex(baseValues, i)) ?: @"";
		[values addObject:multiValue];
	}
	CFRelease(baseValues);
	return values;
}

@end

example.swift

@objc
class ExampleUsingTheAddressBookClass {

	var people: [PersonRecord] = []
	
	init() {
		NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("addressBookChangedNotification:"), name: AddressBookChangedNotification, object: nil)
		loadPeople()
	}
	
	func addressBookChangedNotification(notification: NSNotification) {
		loadPeople()
	}
	
	func loadPeople() {
		AddressBook.performAction { addressBook, error in 
			if let addressBook = addressBook {
				people = addressBook.people
			}
		}
	}
}

PersonRecord.h

#import <Foundation/Foundation.h>

@interface PersonRecord : NSObject

@property (nonatomic, copy) NSString *compositeName;
@property (nonatomic, copy) NSString *organization;
@property (nonatomic, copy) NSString *jobTitle;
@property (nonatomic, copy) NSArray *emails; // of MultiValues
@property (nonatomic, copy) NSArray *phones; // of MultiValues
@end


@interface MultiValue : NSObject

@property (nonatomic, copy) NSString *label;
@property (nonatomic, copy) NSString *value;
@end

PersonRecord.m

#import "PersonRecord.h"


@implementation PersonRecord

@end


@implementation MultiValue

@end