将 NSURLIsExcludedFromBackupKey 应用于 iPhone 上的服务器 URL 或目录 URL

Question

由于我在iPhone上保存一些下载的文件，我正在与应用程序拒绝作斗争。

我已经实现了NSURLIsExcludedFromBackupKey但我不清楚我是否正确。我应该将NSURLIsExcludedFromBackupKey应用于代表服务器上文件的 NSURL，还是以某种方式将其应用于 iPhone 上保存文件的目录？

以下是我在应用程序被拒绝后现在创建的内容：

// Get / Create the File Directory on the iPhone 
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0]; // Get documents folder
NSString *dataPath = [documentsDirectory stringByAppendingPathComponent:@"MyDirectory"];
if (![[NSFileManager defaultManager] fileExistsAtPath:dataPath])
[[NSFileManager defaultManager] createDirectoryAtPath:dataPath withIntermediateDirectories:NO attributes:nil error:nil]; 
// Setup the NSURL where the PNG is located
NSURL *imageURL = [NSURL URLWithString:@"http://www.myserver.com/image.png"];
NSError *err = nil; // Exclude This Image from the iCloud backup system
BOOL excluded = [imageURL setResourceValue:[NSNumber numberWithBool:YES] forKey:NSURLIsExcludedFromBackupKey error:&err];
if (!excluded) {
        //NSLog(@"Failed to exclude from backup");
} else {
    //NSLog(@"Excluding from backup"); // this works...
}
// Create the UIImage
UIImage *image = [[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:imageURL]];
// Data about the downloaded image
NSData *data1 = [NSData dataWithData:UIImagePNGRepresentation(image)];
if ([data1 writeToFile:pngFilePath atomically:YES] && [data1 writeToFile:pngFilePathRetina atomically:YES]) {
        // Saved to phone
} else {        
        // Did not save to phone
}

Answer 1

以下是我最终如何对其进行编码以使其获得批准。这可能有点矫枉过正，但比花一个月的时间试图猜测如何获得批准要好。

 // Get / Create the File Directory on the iPhone 
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0]; // Get documents folder
    NSString *dataPath = [documentsDirectory stringByAppendingPathComponent:@"MyDirectory"];
// if the directory does not yet exist on the phone, create it
    if (![[NSFileManager defaultManager] fileExistsAtPath:dataPath])
    [[NSFileManager defaultManager] createDirectoryAtPath:dataPath withIntermediateDirectories:NO attributes:nil error:nil]; 

    // Assign NSURLIsExcludedFromBackupKey to the directory at dataPath, so is does not backup to iCloud
    NSURL *directoryUrl = [NSURL fileURLWithPath:dataPath isDirectory:YES];
    NSError *err1 = nil;
    BOOL excluded1 = [directoryUrl
                         setResourceValue:[NSNumber numberWithBool:YES]
                         forKey:NSURLIsExcludedFromBackupKey
                         error:&err1];
    if (!excluded1) {
            //NSLog(@"Failed to exclude directory from backup");
    } else {
            //NSLog(@"Excluding directory from backup");
    }

    // Setup the NSURL where the PNG, which will be downloaded, is located 
    NSURL *imageURL = [NSURL URLWithString:@"http://www.myserver.com/image.png"];
    NSError *err2 = nil; // Exclude This Image from the iCloud backup system, Not sure if I need this or not…
    BOOL excluded2 = [imageURL setResourceValue:[NSNumber numberWithBool:YES] forKey:NSURLIsExcludedFromBackupKey error:&err2];
    if (!excluded2) {
        //NSLog(@"Failed to exclude from backup");
    } else {
        //NSLog(@"Excluding from backup"); // this works...
    }

   // Create the UIImage
    UIImage *image = [[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:imageURL]];
    // Data about the downloaded image
    NSData *downloadedImageData = [NSData dataWithData:UIImagePNGRepresentation(image)];
    // Path for where we are going to save the image
    NSString *storePath = [NSString stringWithFormat:@"%@/myimage.png", dataPath]; 
    if ([downloadedImageData writeToFile:storePath atomically:YES]) {
  // the Image is saved to the phone
  // NSURL representing the image that is now saved on the phone          
  NSURL *imageOnPhone = [NSURL fileURLWithPath:storePath isDirectory:YES];
        // Exclude this image, which is now stored on the phone, from iCloud Backup
        NSError *err3 = nil;
        BOOL excluded3 = [imageOnPhone
                                  setResourceValue:[NSNumber numberWithBool:YES]
                                  forKey:NSURLIsExcludedFromBackupKey
                                  error:&err3];
            if (!excluded3) {
                //NSLog(@"Failed to exclude from backup (standard)");
            } else {
                //NSLog(@"Excluding from backup (standard)");
            }
    } else {        
            // Did not save to phone
    }

Answer 2

为了更简洁地回答您的原始问题：

您应该将NSURLIsExcludedFromBackupKey应用于目标，即您不想备份的文件或目录。

iPhone不知道您的应用程序可能正在使用哪些远程文件，因此不可能尝试备份它们。更重要的是，如果您尝试在此类 URL 上设置NSURLIsExcludedFromBackupKey，您很快就会看到它由于 URL 不受支持的而失败。