serialize objective-c custom object to JSON for OSX?

Question

I'm very new to Mac development and I'm having some troubles finding good resources. My current problem is a custom objective-c class object serialization to JSON.

I know that there is a built-in serializer in apple libraries, but that one works only with Foundation objects.

In my case I have my own class that looks like this:

@interface SomeClass : NSObject
{
   int a;
   int b;
   NSString *aa;
   NSString *bb;
}
@property int a,b;
@property NSString *aa,*bb;

@end

If anyone knows how to serialize this type of structure to a JSON please give me a hint! Any kind of relevant information would help! Thank you!

How do you want to serialize the images? Do you want to embed the image data in the JSON, perhaps in PNG or JPEG format? — rob mayoff
– rob mayoff, Commented Oct 9, 2012 at 21:41
oh...sorry...I'll change it to just the simple NSString *imageName — Eugene Gordin
– Eugene Gordin, Commented Oct 9, 2012 at 21:50

rob mayoff · Accepted Answer · 2012-10-09 21:59:27Z

1

If you just want to serialize an object that contains integers and strings, the easiest way is to create a data structure that NSJSONSerialization supports and serialize that:

static const NSString *kAKey = @"a";
static const NSString *kBKey = @"b";
static const NSString *kAaKey = @"aa";
static const NSString *kBbKey = @"bb";

- (id)JSONObject {
    return @{
        kAKey: @(self.a),
        kBKey: @(self.b),
        kAaKey: self.aa,
        kBbKey: self.bb
    };
}

- (NSData *)JSONData {
    return [NSJSONSerialization dataWithJSONObject:[self JSONObject] options:0 error:NULL];
}

answered Oct 9, 2012 at 21:59

rob mayoff

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Comments

Phill Campbell · Accepted Answer · 2016-01-03 03:16:49Z

I have been looking into this for the past week. I decided to write my own solution. It is very simple and built upon existing Apple functionality.

See here: https://github.com/gslinker/GSObject

And here: http://digerati-illuminatus.blogspot.com/2016/01/objective-c-and-json-convert-subclass.html

For your data model object have it inherit from GSObject instead of NSObject. Here is an example of ThingOne with inherits from GSObject:

ThingOne* object1 = [[ThingOne alloc] init];
object1.name = @"John Jones";


NSData* jsonData1 = [object1 toJsonDataWithOptions:NSJSONWritingPrettyPrinted];
NSString *jsonString1 = [object1 toJsonStringWithOptions:NSJSONWritingPrettyPrinted];

NSDictionary<NSString *,id> *dict1 =  [GSObject dictionaryWithValues:object1];

NSString *roundTripJson1 = [object1 toJsonStringWithOptions:NSJSONWritingPrettyPrinted];




//
//  ThingOne.h
//  JasonStuff
//
//  Created by Geoffrey Slinker on 12/28/15.
//  Copyright © 2015 Slinkworks LLC. All rights reserved.
//

#import <Foundation/Foundation.h>
#import "GSObject.h"
#import "ThingTwo.h"

@interface ThingOne : GSObject

@property (nonatomic, retain) NSString *name;
@property (nonatomic, retain) ThingTwo *thingTwo;
@property (nonatomic, retain) NSArray *values;
@property (nonatomic, retain) NSDictionary *dict;
@property int myInt;
@property float myFloat;
@property BOOL myBool;
@property (nonatomic, retain) NSNumber* someMoney;


@end

//
//  ThingOne.m
//  JasonStuff
//
//  Created by Geoffrey Slinker on 12/28/15.
//  Copyright © 2015 Slinkworks LLC. All rights reserved.
//

#import "ThingOne.h"

@implementation ThingOne

@synthesize name;
@synthesize thingTwo;
@synthesize values;
@synthesize dict;
@synthesize myInt;
@synthesize myFloat;
@synthesize myBool;
@synthesize someMoney;

- (instancetype)init
{
self = [super init];

thingTwo = [[ThingTwo alloc] init];

thingTwo.stuff = @"Thing Two Stuff";
thingTwo.someOtherStuff = @"Thing Two Other Stuff";
NSDateFormatter *dateFormater = [[NSDateFormatter alloc]init];
[dateFormater setDateFormat:@"yyyy-mm-dd"];
thingTwo.someDate =  [dateFormater dateFromString:@"1963-10-07"];

values = [NSArray arrayWithObjects:@"Value1", @"Value2", @"Value3", nil];

dict = [NSDictionary dictionaryWithObjectsAndKeys:@"value1", @"key1", @"value2", @"key2", nil];

myInt = 5431;
myFloat = 123.456f;
myBool = YES;

someMoney = [NSNumber numberWithInt:503];

return self;
}

@end

//
//  ThingTwo.h
//  JasonStuff
//
//  Created by Geoffrey Slinker on 12/28/15.
//  Copyright © 2015 Slinkworks LLC. All rights reserved.
//

#import <Foundation/Foundation.h>
#import "GSObject.h"

@interface ThingTwo : GSObject

@property (nonatomic, retain) NSString *stuff;
@property (nonatomic, retain) NSString *someOtherStuff;
@property (nonatomic, retain) NSDate *someDate;
@property (nonatomic, retain) NSString *nullString;
@property (nonatomic, retain) NSDate *nullDate;

@end

//
//  ThingTwo.m
//  JasonStuff
//
//  Created by Geoffrey Slinker on 12/28/15.
//  Copyright © 2015 Slinkworks LLC. All rights reserved.
//

#import "ThingTwo.h"

@implementation ThingTwo

@synthesize stuff;
@synthesize someOtherStuff;
@synthesize someDate;

- (instancetype)init
{
self = [super init];

someDate = [NSDate date];

return self;
}

@end

Here is an example of the JSON output:

{
  "values" : [
    "Value1",
    "Value2",
    "Value3"
  ],
  "myInt" : 5431,
  "myFloat" : 123.456,
  "myBool" : true,
  "someMoney" : "$503.00",
  "thingTwo" : {
    "stuff" : "Thing Two Stuff",
    "nullDate" : null,
    "someDate" : "1963-01-07 07:10:00 +0000",
    "nullString" : null,
    "someOtherStuff" : "Thing Two Other Stuff"
  },
  "name" : "John Jones",
  "dict" : {
    "key1" : "value1",
    "key2" : "value2"
  }
}

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