KeychainHelper - Simple Keychain access for iOS Keychain Services

KeychainHelper.h

//
//  KeychainHelper.h


#import <Foundation/Foundation.h>

@interface KeychainHelper : NSObject

@property (strong, nonatomic) NSMutableDictionary * keychainItem;


- (void)saveKeychainWithEmail:(NSString *)email andToken: (NSString *)token;

- (NSString *)getAuthToken;

- (NSString *)getEmail;


@end

KeychainHelper.m

//
//  KeychainHelper.m

#import "KeychainHelper.h"
#import <Security/Security.h>

@interface KeychainHelper ()


@end

static const NSString * WEBSITE = @"www.yoursite.com";


@implementation KeychainHelper


- (NSMutableDictionary *)createEmptyKeychainItem{
    
    //Let's create an empty mutable dictionary:
    _keychainItem = [NSMutableDictionary dictionary];
    
    //Populate it with the data and the attributes we want to use.
    
    _keychainItem[(__bridge id)kSecClass] = (__bridge id)kSecClassInternetPassword; // We specify what kind of keychain item this is.
    _keychainItem[(__bridge id)kSecAttrAccessible] = (__bridge id)kSecAttrAccessibleWhenUnlocked; // This item can only be accessed when the user unlocks the device.
    
    _keychainItem[(__bridge id)kSecAttrServer] = WEBSITE;
    
    _keychainItem[(__bridge id)kSecReturnData] = (__bridge id)kCFBooleanTrue;
    _keychainItem[(__bridge id)kSecReturnAttributes] = (__bridge id)kCFBooleanTrue;
    
    
    
    
    return nil;
}


- (void)saveKeychainWithEmail: (NSString *) email andToken: (NSString *)token{
    
    [self createEmptyKeychainItem];

    
    //Check if this keychain item already exists.
    
    if(SecItemCopyMatching((__bridge CFDictionaryRef)_keychainItem, NULL) == noErr)
    {
        
        //Item Already Exists == Update instead
        [self updateKeychainItemWithEmail:email andToken:token];
        
    } else {
        
        
        //Item does not exist -- create new
        _keychainItem[(__bridge id)kSecValueData] = [token dataUsingEncoding:NSUTF8StringEncoding];
        _keychainItem[(__bridge id)kSecAttrAccount] = email;


        
        OSStatus sts = SecItemAdd((__bridge CFDictionaryRef)_keychainItem, NULL);
        NSLog(@"Error Code: %d", (int)sts);
    }
}

- (void)updateKeychainItemWithEmail:(NSString *)email andToken:(NSString *)token{


        
    NSMutableDictionary *attributesToUpdate = [NSMutableDictionary dictionary];
    attributesToUpdate[(__bridge id)kSecValueData] = [token dataUsingEncoding:NSUTF8StringEncoding];
    attributesToUpdate[(__bridge id)kSecAttrAccount] = email;
    
      //Must set these back to false for SecItemUpdate to work
    _keychainItem[(__bridge id)kSecReturnData] = (__bridge id)kCFBooleanFalse;
    _keychainItem[(__bridge id)kSecReturnAttributes] = (__bridge id)kCFBooleanFalse;


    
    
    OSStatus sts = SecItemUpdate((__bridge CFDictionaryRef)_keychainItem, (__bridge CFDictionaryRef)attributesToUpdate);
    NSLog(@"Error Code: %d", (int)sts);
 
}

- (NSString *)getAuthToken{

    CFDictionaryRef result = nil;
    
    [self createEmptyKeychainItem];
    
    OSStatus sts = SecItemCopyMatching((__bridge CFDictionaryRef)_keychainItem, (CFTypeRef *)&result);
    
    NSLog(@"Error Code: %d", (int)sts);
    
    if(sts == noErr)
    {
        NSDictionary *resultDict = (__bridge_transfer NSDictionary *)result;
        NSData *tokenData = resultDict[(__bridge id)kSecValueData];
        NSString *token = [[NSString alloc] initWithData:tokenData encoding:NSUTF8StringEncoding];
        
        return token;
    }else
    {
        NSLog(@"No Keychain found for user");
        return nil;
    }
}


- (NSString *)getEmail{
    
    CFDictionaryRef result = nil;
    
    [self createEmptyKeychainItem];
    
    OSStatus sts = SecItemCopyMatching((__bridge CFDictionaryRef)_keychainItem, (CFTypeRef *)&result);
    
    NSLog(@"Error Code: %d", (int)sts);
    
    if(sts == noErr)
    {
        NSDictionary *resultDict = (__bridge_transfer NSDictionary *)result;
        
        return resultDict[(__bridge id)kSecAttrAccount];
;
    }else
    {
        NSLog(@"No Keychain found for user");
        return nil;
    }
}



@end