How do I get NSJSONSerialization to output a boolean as true or false?

Question

I'm using NSJSONSerialization dataWithJSONObject to serialize my classes to JSON. When it serializes a BOOL, it gives it the value 1 or 0 in the JSON string. I need this to be true or false instead. Is this possible to do generically?

Answer 1

When I create [NSNumber numberWithBool:NO], the NSJSONSerialization returns the word "false" in the JSON string.

EDIT With the new shortcuts you can also use these handy guys:

@(YES) /   @(NO)
@(1)   /   @(0)
@YES   /   @NO
@1     /   @0

This way you can avoid something like looping through your values. I want the exact opposite behavior but have NSNumber objects. So I have to loop...

EDIT II

mbi pointed out in the comments that there is a difference between iOS versions. So here is an iOS9 test:

NSDictionary *data = @{
    @"a": @(YES),
    @"b": @YES,
    @"c": @(1),
    @"d": @1
};
NSLog(@"%@", [[NSString alloc] initWithData:[NSJSONSerialization dataWithJSONObject:data options:0 error:nil] encoding:NSUTF8StringEncoding]);

2016-07-05 02:23:43.964 Test App[24581:6231996] {"a":true,"b":true,"c":1,"d":1}

Answer 2

Just ran across this myself, not sure if this is the best answer but...

Make sure to use @YES or @NO, then your outputted json will have true / false in it:

[NSJSONSerialization dataWithJSONObject:@{@"test": @YES} options:0 error: nil];

So you will have to turn your other "booleans" / boolean like values -> @YES / @NO when putting into the dictionary for dataWithJSONObject.

[NSJSONSerialization dataWithJSONObject:@{@"test": (boolLikeValue ? @YES : @NO)} options:0 error: nil];

Answer 3

Yes, it is possible to output a boolean (true/false) with NSJSONSerialization by using kCFBooleanTrue and kCFBooleanFalse :

NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:kCFBooleanTrue, @"key_1",
                           kCFBooleanFalse, @"key_2",
                           nil]  

then

NSError *error = nil;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dict options:kNilOptions error:&error];

Answer 4

No, the Foundation Object for a Bool is NSNumber numberWithBool, which becomes either 0 or 1. We have no Bool Object. Same go for reading JSON. True/false will become a NSNumber again.

You could create an Bool Class and build your own parser. Arrays are Arrays and JSON Objects are NSDictionary. You can query the keys, test what Class lies behind and build the JSON String from this.