问题
目前需要保存一些用户配置，在app删掉后依然能正常读取，那么就用到【钥匙串】
钥匙串简介
项目中有时会需要存储敏感信息（如密码、密钥等），苹果官方提供了一种存储机制--钥匙串（keychain）。
keychain是一种存储在硬盘上的加密的数据库。这个可能是卸载App后，keychain信息还在的原因。
keychain适合存储 较小的数据量（不超过上千字节或上兆字节）的内容。
解决方案
JJKeychain.h
@interface JJKeychain : NSObject
//保存是先删掉之前的key，没有使用update，感觉这样简单；然后保存的value转换为NSData，如果value为自定义object，则需遵循NSSecureCoding协议
+ (BOOL)setValue:(id)value forKey:(NSString *)key;
+ (BOOL)setValue:(id)value forKey:(NSString *)key forAccessGroup:(nullable NSString *)group;
+ (id)valueForKey:(NSString *)key;
+ (id)valueForKey:(NSString *)key forAccessGroup:(nullable NSString *)group;
+ (BOOL)deleteValueForKey:(NSString *)key;
+ (BOOL)deleteValueForKey:(NSString *)key forAccessGroup:(nullable NSString *)group;
+ (NSString *)getBundleSeedIdentifier;
@end
JJKeychain.m
@implementation JJKeychain
+ (NSMutableDictionary *)getKeychainQuery:(NSString *)key forAccessGroup:(NSString *)group{
NSMutableDictionary *query = @{(__bridge id)kSecClass : (__bridge id)kSecClassGenericPassword,
(__bridge id)kSecAttrService : key,
(__bridge id)kSecAttrAccount : key,
(__bridge id)kSecAttrAccessible : (__bridge id)kSecAttrAccessibleAfterFirstUnlock
}.mutableCopy;
if (group != nil) {
[query setObject:[self getFullAccessGroup:group] forKey:(__bridge id)kSecAttrAccessGroup];
}
return query;
}
+ (NSString *)getFullAccessGroup:(NSString *)group
{
NSString *accessGroup = nil;
NSString *bundleSeedIdentifier = [self getBundleSeedIdentifier];
if (bundleSeedIdentifier != nil && [group rangeOfString:bundleSeedIdentifier].location == NSNotFound) {
accessGroup = [NSString stringWithFormat:@"%@.%@", bundleSeedIdentifier, group];
}
return accessGroup;
}
+ (NSString *)getBundleSeedIdentifier
{
static __strong NSString *bundleSeedIdentifier = nil;
if (bundleSeedIdentifier == nil) {
@synchronized(self) {
if (bundleSeedIdentifier == nil) {
NSString *_bundleSeedIdentifier = nil;
NSDictionary *query = @{
(__bridge id)kSecClass: (__bridge NSString *)kSecClassGenericPassword,
(__bridge id)kSecAttrAccount: @"bundleSeedID",
(__bridge id)kSecAttrService: @"",
(__bridge id)kSecReturnAttributes: (__bridge id)kCFBooleanTrue
};
CFDictionaryRef result = nil;
OSStatus status = SecItemCopyMatching((__bridge CFDictionaryRef)query, (CFTypeRef *)&result);
if (status == errSecItemNotFound) {
status = SecItemAdd((__bridge CFDictionaryRef)query, (CFTypeRef *)&result);
}
if (status == errSecSuccess) {
NSString *accessGroup = [(__bridge NSDictionary *)result objectForKey:(__bridge NSString *)kSecAttrAccessGroup];
NSArray *components = [accessGroup componentsSeparatedByString:@"."];
// NSLog(@"components %@",components);
_bundleSeedIdentifier = [[components objectEnumerator] nextObject];
CFRelease(result);
}
if (_bundleSeedIdentifier != nil) {
bundleSeedIdentifier = [_bundleSeedIdentifier copy];
}
}
}
}
return bundleSeedIdentifier;
}
+ (BOOL)setValue:(id)value forKey:(NSString *)key{
return [self setValue:value forKey:key forAccessGroup:nil];
}
+ (BOOL)setValue:(id)value forKey:(NSString *)key forAccessGroup:(NSString *)group{
NSMutableDictionary *query = [self getKeychainQuery:key forAccessGroup:group];
[self deleteValueForKey:key forAccessGroup:group];
NSData *data = nil;
@try {
data = [NSKeyedArchiver archivedDataWithRootObject:value];
} @catch (NSException *exception) {
NSLog(@"archived failure value %@ %@",value,exception);
return NO;
}
[query setObject:data forKey:(__bridge id)kSecValueData];
OSStatus result = SecItemAdd((__bridge CFDictionaryRef)query, NULL);
return result == errSecSuccess;
}
+ (BOOL)deleteValueForKey:(NSString *)key{
return [self deleteValueForKey:key forAccessGroup:nil];
}
+ (BOOL)deleteValueForKey:(NSString *)key forAccessGroup:(NSString *)group{
NSMutableDictionary *query = [self getKeychainQuery:key forAccessGroup:group];
OSStatus result = SecItemDelete((__bridge CFDictionaryRef)query);
return result == errSecSuccess;
}
+ (id)valueForKey:(NSString *)key{
return [self valueForKey:key forAccessGroup:nil];
}
+ (id)valueForKey:(NSString *)key forAccessGroup:(NSString *)group{
id value = nil;
NSMutableDictionary *query = [self getKeychainQuery:key forAccessGroup:group];
CFDataRef keyData = NULL;
[query setObject:(__bridge id)kCFBooleanTrue forKey:(__bridge id)kSecReturnData];
[query setObject:(__bridge id)kSecMatchLimitOne forKey:(__bridge id)kSecMatchLimit];
if (SecItemCopyMatching((__bridge CFDictionaryRef)query, (CFTypeRef *)&keyData) == errSecSuccess) {
@try {
value = [NSKeyedUnarchiver unarchiveObjectWithData:(__bridge NSData *)keyData];
}
@catch (NSException *e) {
NSLog(@"Unarchive of %@ failed: %@", key, e);
value = nil;
}
}
if (keyData) {
CFRelease(keyData);
}
return value;
}
@end
