Load file in Today extension when device is locked

问题:

In my today extension with my device unlocked, this line of code works as expected, returning the data from the image path:

let imageData = NSData(contentsOfFile: path)

However when my device is locked with a passcode, it returns nil. Is there any way to access images in the file system when the device is locked? I can access UserDefaults just fine, but not files in the directory for my shared group. Here is how I am creating the path, calling imagePath, which is correctly populated with the path I expect in both cases:

func rootFilePath() -> String? {
    let manager = NSFileManager()
    let containerURL = manager.containerURLForSecurityApplicationGroupIdentifier(GROUP_ID)
    if let unwrappedURL = containerURL {
        return unwrappedURL.path
    }
    else {
        return nil
    }
}

func imagePath() -> String? {
    let rootPath = rootFilePath()
    if let uPath = rootPath {
        return "\(uPath)/\(imageId).png"
    }
    else {
        return nil
    }
}

回答1:

I just figured it out! You need to set the file permissions accordingly:

NSFileManager *fm = [[NSFileManager alloc] init];
NSDictionary *attribs = @{NSFileProtectionKey : NSFileProtectionNone};
NSError *unprotectError = nil;

BOOL unprotectSuccess = [fm setAttributes:attribs
                             ofItemAtPath:[containerURL path]
                                    error:&unprotectError];
if (!unprotectSuccess) {
    NSLog(@"Unable to remove protection from file! %@", unprotectError);
}

In many cases you wouldn't normally want to do this, but because the information is intended to be viewed from the lock screen, I'm OK with removing file protection.