APP沙盒结构文件分析及数据存储

1.沙盒目录

1.1 Documents：默认备份的 itunes iCloud 注意：存储大文件（视频），可能会被审核拒绝

1.2 Libuary: Caches(系统缓存的：网络数据)、Preferences(系统是默认备份的 NSUserDefaults)

1.3 tmp：临时文件夹

1.4 SystemData：暂时没发现啥用处

对于默认备份，可以设置为非备份，代码如下：

NSString *filePath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
    NSLog(@"%@", filePath);
    
    
    [self addSkipBackupAttributeToItemAtURL:[NSURL fileURLWithPath:filePath]];

// 设置非备份
- (BOOL)addSkipBackupAttributeToItemAtURL:(NSURL*)URL
{
    const char* filePath = [[URL path] fileSystemRepresentation];
    const char* attrName = "com.apple.MobileBackup";
    u_int8_t attrValue = 1;
    
    int result = setxattr(filePath, attrName, &attrValue, sizeof(attrValue), 0, 0);
    return result == 0;
}

对于通过NSUserDefaults数据修改，它会有一段时间去合并之前与现在的更改，所有会导致有时候读取数据出错。需要进行同步操作[[NSUserDefaults standardUserDefaults] synchronize];

- (void)saveUserDefaultOne {
    [[NSUserDefaults standardUserDefaults] setObject:@"QQQQ" forKey:@"TG"];
}
- (void)saveUserDefaultTwo {
    [[NSUserDefaults standardUserDefaults] setObject:@"TTTT" forKey:@"TGG"];
    [[NSUserDefaults standardUserDefaults] setObject:@"AAAAA" forKey:@"TG"];
    [[NSUserDefaults standardUserDefaults] synchronize];
}

对于网络请求，系统会把请求的信息数据保存在Libuary: Caches文件夹下面

查看方法，1. cd Libuary/Caches/assdada 2. sqlite3 Cache.db 3. .table 4. select * from cfurl_cache_blob_data 5 select * from cfurl_cache_receiver_data

2. Bundle:资源文件，不参与编译；

黄色/蓝色文件夹蓝色文件夹不参与编译

加载bundle里面的资源文件

NSString *boudlePath = [[NSBundle mainBundle] pathForResource:@"TGBundle" ofType:@"bundle"];
    
    NSBundle *tgBoundle = [NSBundle bundleWithPath:boudlePath];
    
    NSString *imagePath = [tgBoundle pathForResource:@"11" ofType:@"png"];
    
    //_imageView.image = [UIImage imageWithContentsOfFile:imagePath];
//    _imageView.image = [UIImage imageNamed:@"TGBundle.bundle/11.png"];
    _imageView.image = [UIImage imageNamed:@"11.png"];  // 加载不到图片文件

3. 归档解档

遵循代理<NSCoding>

实现方法：

归档： - (void)encodeWithCoder:(NSCoder *)aCoder

解档：- (nullable instancetype)initWithCoder:(NSCoder *)aDecoder

@interface TGObject : NSObject<NSCoding>
@property (nonatomic, strong)NSString *name;
@property (nonatomic, strong)NSString *age;
@end

#import "TGObject.h"

@implementation TGObject

- (void)encodeWithCoder:(NSCoder *)aCoder{
    
    [aCoder encodeObject:self.name forKey:@"name"];
    [aCoder encodeObject:self.age forKey:@"age"];
    
}

// 解当
- (nullable instancetype)initWithCoder:(NSCoder *)aDecoder{
    
    
    TGObject *object = [TGObject new];
    
    object.name = [aDecoder decodeObjectForKey:@"name"];
    object.age = [aDecoder decodeObjectForKey:@"age"];
    
    return object;
}

@end

4. 钥匙串的存储

4.1 不会因为应用的删除而导致数据丢失，底层用的sql，操作数据库，加密的存储，存密码之类，实现增删改查

4.2 跨应用间的数据访问