NSSecureCoding自定义类集合的麻烦 [英] NSSecureCoding trouble with collections of custom class

问题描述

我在采用NSSecureCoding时遇到了麻烦.我对包含自定义类的对象的数组进行编码，该类正确采用了NSSecureCoding.当我解码它时，传递类NSArray(这是我编码的对象的类)，它将引发异常.但是，当完全相同的事情与字符串数组一起使用时，它可以很好地工作.我看不到我的类和NSString有什么区别.

I am having trouble with adopting NSSecureCoding. I encode an array containing objects of my custom class, which adopts NSSecureCoding properly. When I decode it, passing the class NSArray (which is the class of the object I encoded), it throws an exception. However, when do the exact same thing with an array of strings, it works fine. I fail to see what is the difference between my class and NSString.

#import <Foundation/Foundation.h>

@interface Foo : NSObject <NSSecureCoding>
@end
@implementation Foo
- (id)initWithCoder:(NSCoder *)aDecoder {
  return [super init];
}
- (void)encodeWithCoder:(NSCoder *)aCoder {
}
+ (BOOL)supportsSecureCoding {
  return YES;
}
@end

int main() {
  @autoreleasepool {

    NSMutableData* data = [[NSMutableData alloc] init];
    NSKeyedArchiver* archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
    [archiver encodeObject:@[[Foo new]] forKey:@"foo"];
    [archiver encodeObject:@[@"bar"] forKey:@"bar"];
    [archiver finishEncoding];

    NSKeyedUnarchiver* unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];
    unarchiver.requiresSecureCoding = YES;
    // throws exception: 'value for key 'NS.objects' was of unexpected class 'Foo'. Allowed classes are '{( NSArray )}'.'
    [unarchiver decodeObjectOfClass:[NSArray class] forKey:@"foo"];
    // but this line works fine:
    [unarchiver decodeObjectOfClass:[NSArray class] forKey:@"bar"];
    [unarchiver finishDecoding];

  }
  return 0;
}

推荐答案

您可能已经解决了这个问题，但是我刚刚找到了解决方案，并认为我会将它留给所有找到此解决方案的人使用.

You've probably already solved this, but I just hit this and found a solution, and thought I'd leave it here for anyone else that finds this.

我的解决方案是使用decodeObjectOfClasses:forKey:

迅速:

    if let data = defaults.objectForKey(FinderSyncKey) as? NSData
        let unArchiver = NSKeyedUnarchiver(forReadingWithData: data)
        unArchiver.setRequiresSecureCoding(true)
         //This line is most likely not needed, I was decoding the same object across modules
        unArchiver.setClass(CustomClass.classForCoder(), forClassName: "parentModule.CustomClass")
        let allowedClasses = NSSet(objects: NSArray.classForCoder(),CustomClass.classForCoder())
        if let unarchived = unArchiver.decodeObjectOfClasses(allowedClasses, forKey:NSKeyedArchiveRootObjectKey) as?  [CustomClass]{
            return unarchived

        }    
    }

在Objective-C中，它类似于[unArchiver decodeObjectOfClasses:allowedClasses forKey:NSKeyedArchiveRootObjectKey]

in objective-C it would be something like [unArchiver decodeObjectOfClasses:allowedClasses forKey:NSKeyedArchiveRootObjectKey]

将解码对象更改为解码对象对我来说解决了上述异常.

The change in decode object to decode objects solved the above exception for me.

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