将唯一 ID 实现为 UUID 并将其保存在 Keychain 中

我的应用程序中需要唯一 ID，我知道，我们不能再使用 UDID，因此根据我的研究，使用 UUID 作为设备唯一 ID 并将其保存在钥匙串中将确保即使用户重新安装我的应用程序，唯一 ID 仍保持不变。

我从 stackoverflow 上类似问题的答案之一找到了以下代码，但是，我需要知道如何访问 keychainUtils 和 IDManager？ 提前感谢您的帮助。

+ (NSString *) getUniqueUUID {
    NSError * error;
    NSString * uuid = [KeychainUtils getPasswordForUsername:USER_NAME   andServiceName:SERVICE_NAME error:&error];
    if (error) {
        NSLog(@"Error geting unique UUID for this device! %@", [error localizedDescription]);
        return nil;
    }
    if (!uuid) {
        DLog(@"No UUID found. Creating a new one.");
        uuid = [IDManager GetUUID];
        uuid = [Util md5String:uuid];
        [KeychainUtils storeUsername:kBuyassUser andPassword:uuid forServiceName:kIdOgBetilngService updateExisting:YES error:&error];
        if (error) {
            NSLog(@"Error geting unique UUID for this device! %@", [error localizedDescription]);
            return nil;
        }
    }
    return uuid;
}

我想提供这个作为解决方案。它不需要第三方代码。如果确实需要，它会读取或写入 KeyChain，因此它比迄今为止提供的解决方案更有效。此外，UUID 会写入钥匙串访问组，以便您可以在应用程序之间共享此 UUID。只需改变kKeyChainVendorIDAccessGroup在方法的开始处。

+(NSUUID *)persistentIdentifierForVendor
{
    static NSString * const kKeyChainVendorID = @"co.cwbrn.PersistentIdentifier";
    static NSString * const kKeyChainVendorIDAccessGroup = @"<AppIdentifier>.<keychain-access-group-identifier>";

    // First, check NSUserDefaults so that we're not hitting the KeyChain every single time
    NSString *uuidString = [[NSUserDefaults standardUserDefaults] stringForKey:kKeyChainVendorIDGroup];
    BOOL vendorIDMissingFromUserDefaults = (uuidString == nil || uuidString.length == 0);

    if (vendorIDMissingFromUserDefaults) {
        // Check to see if a UUID is stored in the KeyChain
        NSDictionary *query = @{
                                (__bridge id)kSecClass:             (__bridge id)kSecClassGenericPassword,
                                (__bridge id)kSecAttrAccount:       kKeyChainVendorID,
                                (__bridge id)kSecAttrService:       kKeyChainVendorID,
                                (__bridge id)kSecAttrAccessGroup:   kKeyChainVendorIDAccessGroup,
                                (__bridge id)kSecMatchLimit:        (__bridge id)kSecMatchLimitOne,
                                (__bridge id)kSecReturnAttributes:  (__bridge id)kCFBooleanTrue
                               };
        CFTypeRef attributesRef = NULL;
        OSStatus result = SecItemCopyMatching((__bridge CFDictionaryRef)query, &attributesRef);
        if (result == noErr) {
            // There is a UUID, so try to retrieve it
            NSDictionary *attributes = (__bridge_transfer NSDictionary *)attributesRef;
            NSMutableDictionary *valueQuery = [NSMutableDictionary dictionaryWithDictionary:attributes];

            [valueQuery setObject:(__bridge id)kSecClassGenericPassword  forKey:(__bridge id)kSecClass];
            [valueQuery setObject:(__bridge id)kCFBooleanTrue            forKey:(__bridge id)kSecReturnData];

            CFTypeRef passwordDataRef = NULL;
            OSStatus result = SecItemCopyMatching((__bridge CFDictionaryRef)valueQuery, &passwordDataRef);
            if (result == noErr) {
                NSData *passwordData = (__bridge_transfer NSData *)passwordDataRef;
                uuidString = [[NSString alloc] initWithBytes:[passwordData bytes]
                                                      length:[passwordData length]
                                                    encoding:NSUTF8StringEncoding];
            }
        }
    }

    // Failed to read the UUID from the KeyChain, so create a new UUID and store it
    if (uuidString == nil || uuidString.length == 0) {
        // Generate the new UIID
        CFUUIDRef uuidRef = CFUUIDCreate(kCFAllocatorDefault);
        uuidString = (__bridge_transfer NSString *)CFUUIDCreateString(kCFAllocatorDefault, uuidRef);
        CFRelease(uuidRef);

        // Now store it in the KeyChain
        NSDictionary *query = @{    (__bridge id)kSecClass:             (__bridge id)kSecClassGenericPassword,
                                    (__bridge id)kSecAttrAccount:       kKeyChainVendorID,
                                    (__bridge id)kSecAttrService:       kKeyChainVendorID,
                                    (__bridge id)kSecAttrAccessGroup:   kKeyChainVendorIDAccessGroup,
                                    (__bridge id)kSecAttrLabel:         @"",
                                    (__bridge id)kSecAttrDescription:   @"",
                                    (__bridge id)kSecAttrAccessible:    (__bridge id)kSecAttrAccessibleAfterFirstUnlock,
                                    (__bridge id)kSecValueData:         [uuidString dataUsingEncoding:NSUTF8StringEncoding]
                                };

        OSStatus result = SecItemAdd((__bridge CFDictionaryRef)query, NULL);
        if (result != noErr) {
            NSLog(@"ERROR: Couldn't add to the Keychain. Result = %ld; Query = %@", result, query);
            return nil;
        }
    }

    // Save UUID to NSUserDefaults so that we can avoid the KeyChain next time
    if (vendorIDMissingFromUserDefaults) {
        [[NSUserDefaults standardUserDefaults] setObject:uuidString forKey:kKeyChainVendorIDGroup];
    }

    return [[NSUUID alloc] initWithUUIDString:uuidString];
}