iOS编程——经过UUID和KeyChain来代替Mac地址实现iOS设备的唯一标示(OC版)

iOS编程——通过UUID和KeyChain来代替Mac地址实现iOS设备的唯一标示(OC版)

很多的应用都需要用到手机的唯一标示，而且要求这个唯一标示不能因为应用app的卸载或者改变而变化。

在iOS7以前是可以通过Mac地址来实现这个功能的，但是iOS7(包含)以后是无法获得Mac地址的；苹果官方推荐使用UUID，但是每次随着APP的卸载重装，UUID会随之发生变化，那该如何处理呢？

我们需要一个能在app卸载重装后不会改变的值，而keyChain恰巧就可以做到。配合UUID就可以实现了！让我们来分析下：

1.我们首先需要导入Security.frameWork（keychain依赖它），然后需要一个keychain管理器，一个uuid管理器，文件组成如下：

2.首先来看MyKeychainManager,其实就是对keychain的增、删、改、查，类似于数据库的处理。

先通过.h文件来开放下增、删、改、查四个接口：

#import <Foundation/Foundation.h>

@interface MyKeyChainManager : NSObject

+ (NSMutableDictionary *)getKeychainQuery:(NSString *)service;

+ (void)save:(NSString *)service data:(id)data;

+ (id)load:(NSString *)service;

+ (void)delete:(NSString *)service;
    
@end

.m文件实现接口，keychain的使用网上很多，直接贴代码了：

#import "MyKeyChainManager.h"

@implementation MyKeyChainManager : NSObject 

+ (NSMutableDictionary *)getKeychainQuery:(NSString *)service {
    return [NSMutableDictionary dictionaryWithObjectsAndKeys:
            (__bridge_transfer id)kSecClassGenericPassword,(__bridge_transfer id)kSecClass,
            service, (__bridge_transfer id)kSecAttrService,
            service, (__bridge_transfer id)kSecAttrAccount,
            (__bridge_transfer id)kSecAttrAccessibleAfterFirstUnlock,(__bridge_transfer id)kSecAttrAccessible,
            nil];
}

+ (void)save:(NSString *)service data:(id)data {
    //Get search dictionary
    NSMutableDictionary *keychainQuery = [self getKeychainQuery:service];
    //Delete old item before add new item
    SecItemDelete((__bridge_retained CFDictionaryRef)keychainQuery);
    //Add new object to search dictionary(Attention:the data format)
    [keychainQuery setObject:[NSKeyedArchiver archivedDataWithRootObject:data] forKey:(__bridge_transfer id)kSecValueData];
    //Add item to keychain with the search dictionary
    SecItemAdd((__bridge_retained CFDictionaryRef)keychainQuery, NULL);
}

+ (id)load:(NSString *)service {
    id ret = nil;
    NSMutableDictionary *keychainQuery = [self getKeychainQuery:service];
    //Configure the search setting
    [keychainQuery setObject:(id)kCFBooleanTrue forKey:(__bridge_transfer id)kSecReturnData];
    [keychainQuery setObject:(__bridge_transfer id)kSecMatchLimitOne forKey:(__bridge_transfer id)kSecMatchLimit];
    CFDataRef keyData = NULL;
    if (SecItemCopyMatching((__bridge_retained CFDictionaryRef)keychainQuery, (CFTypeRef *)&keyData) == noErr) {
        @try {
            ret = [NSKeyedUnarchiver unarchiveObjectWithData:(__bridge_transfer NSData *)keyData];
        } @catch (NSException *e) {
            NSLog(@"Unarchive of %@ failed: %@", service, e);
        } @finally {
        }
    }
    return ret;
}

+ (void)delete:(NSString *)service {
    NSMutableDictionary *keychainQuery = [self getKeychainQuery:service];
    SecItemDelete((__bridge_retained CFDictionaryRef)keychainQuery);
}

@end

3.再来看下MyUUIDManager文件，实现的是对UUID的增、删、改、查，其中save既是增也是改：

#import <Foundation/Foundation.h>

@interface MyUUIDManager: NSObject

+(void)saveUUID:(NSString *)uuid;

+(NSString *)getUUID;

+(void)deleteUUID;

@end

.m文件来实现它：

#import "MyUUIDManager.h"
#import "MyKeyChainManager.h"

@implementation MyUUIDManager

static NSString * const KEY_IN_KEYCHAIN = @"com.myuuid.uuid";


+(void)saveUUID:(NSString *)uuid{
    if (uuid && uuid.length > 0) {
        [MyKeyChainManager save:KEY_IN_KEYCHAIN data:uuid];
    }
}


+(NSString *)getUUID{
    //先获取keychain里面的UUID字段，看是否存在
    NSString *uuid = (NSString *)[MyKeyChainManager load:KEY_IN_KEYCHAIN];
    
    //如果不存在则为首次获取UUID，所以获取保存。
    if (!uuid || uuid.length == 0) {
        CFUUIDRef puuid = CFUUIDCreate( nil );
        
        CFStringRef uuidString = CFUUIDCreateString( nil, puuid );
        
        uuid = [NSString stringWithFormat:@"%@", uuidString];
        
        [self saveUUID:uuid];
        
        CFRelease(puuid);
        
        CFRelease(uuidString);
    }
    
    return uuid;
}



+(void)deleteUUID{
    [MyKeyChainManager delete:KEY_IN_KEYCHAIN];
}


@end

4.测试一下：

NSString *uuid = [MyUUIDManager getUUID];
    NSLog(@"uuid: %@",uuid);
2015-08-10 18:14:07.641 MyTest[3190:220331] uuid: 839E055B-09A5-42E1-A46C-DF4481E23333

5.把app删除掉重新安装一下，再打印一下：

2015-08-10 18:22:37.122 MyTest[3214:222053] uuid: 839E055B-09A5-42E1-A46C-DF4481E23333