Magical Data Modelling Framework for JSON

JSONModel is a library, which allows rapid creation of smart data models. You can use it in your iOS or OSX apps.

JSONModel automatically introspects your model classes and the structure of your JSON input and reduces drastically the amount of code you have to write.

Adding JSONModel to your project

Requirements

ARC only; iOS 5.0+ / OSX 10.7+
SystemConfiguration.framework

Get it as: 1) source files

Download the JSONModel repository as a zip file or clone it
Copy the JSONModel sub-folder into your Xcode project
Link your app to SystemConfiguration.framework

or 2) via Cocoa pods

In your project's Podfile add the JSONModel pod:

pod 'JSONModel'

If you want to read more about CocoaPods, have a look at this short tutorial.

Source code documentation

The source code includes class docs, which you can build yourself and import into Xcode:

If you don't already have appledoc installed, install it with homebrew by typing brew install appledoc.
Install the documentation into Xcode by typing appledoc . in the root directory of the repository.
Restart Xcode if it's already running.

Basic usage

Consider you have a JSON like this:

{"id":"10", "country":"Germany", "dialCode": 49, "isInEurope":true}

Create a new Objective-C class for your data model and make it inherit the JSONModel class.
Declare properties in your header file with the name of the JSON keys:

#import "JSONModel.h"

@interface CountryModel : JSONModel

@property (assign, nonatomic) int id;
@property (strong, nonatomic) NSString* country;
@property (strong, nonatomic) NSString* dialCode;
@property (assign, nonatomic) BOOL isInEurope;

@end

There's no need to do anything in the .m file.

Initialize your model with data:

#import "CountryModel.h"
...

NSString* json = (fetch here JSON from Internet) ... 
NSError* err = nil;
CountryModel* country = [[CountryModel alloc] initWithString:json error:&err];

If the validation of the JSON passes you have all the corresponding properties in your model populated from the JSON. JSONModel will also try to convert as much data to the types you expect, in the example above it will:

convert "id" from string (in the JSON) to an int for your class
just copy country's value
convert dialCode from number (in the JSON) to an NSString value
finally convert isInEurope to a BOOL for your BOOL property

And the good news is all you had to do is define the properties and their expected types.

Online tutorials

Official website: http://www.jsonmodel.com

Class docs online: http://jsonmodel.com/docs/

Step-by-step tutorials:

Examples

Automatic name based mapping

{
  "id": "123",
  "name": "Product name",
  "price": 12.95
}

@interface ProductModel : JSONModel
@property (assign, nonatomic) int id;
@property (strong, nonatomic) NSString* name;
@property (assign, nonatomic) float price;
@end
@implementation ProductModel
@end

Model cascading (models including other models)

{
  "order_id": 104,
  "total_price": 13.45,
  "product" : {
    "id": "123",
    "name": "Product name",
    "price": 12.95
  }
}

@interface OrderModel : JSONModel
@property (assign, nonatomic) int order_id;
@property (assign, nonatomic) float total_price;
@property (strong, nonatomic) ProductModel* product;
@end
@implementation OrderModel
@end

Model collections

{
  "order_id": 104,
  "total_price": 103.45,
  "products" : [
    {
      "id": "123",
      "name": "Product #1",
      "price": 12.95
    },
    {
      "id": "137",
      "name": "Product #2",
      "price": 82.95
    }
  ]
}

@protocol ProductModel
@end
@interface ProductModel : JSONModel
@property (assign, nonatomic) int id;
@property (strong, nonatomic) NSString* name;
@property (assign, nonatomic) float price;
@end
@implementation ProductModel
@end
@interface OrderModel : JSONModel
@property (assign, nonatomic) int order_id;
@property (assign, nonatomic) float total_price;
@property (strong, nonatomic) NSArray<ProductModel>* products;
@end
@implementation OrderModel
@end

Key mapping

{
  "order_id": 104,
  "order_details" : [
    {
      "name": "Product#1",
      "price": {
        "usd": 12.95
      }
    }
  ]
}

@interface OrderModel : JSONModel
@property (assign, nonatomic) int id;
@property (assign, nonatomic) float price;
@property (strong, nonatomic) NSString* productName;
@end
@implementation OrderModel
+(JSONKeyMapper*)keyMapper
{
return [[JSONKeyMapper alloc] initWithDictionary:@{
  @"order_id": @"id",
@"order_details.name": @"productName",
@"order_details.price.usd": @"price"
}];
}
@end

Global key mapping (applies to all models in your app)

[JSONModel setGlobalKeyMapper:[
    [JSONKeyMapper alloc] initWithDictionary:@{
      @"item_id":@"ID",
      @"item.name": @"itemName"
   }]
];

Map automatically under_score case to camelCase

{
  "order_id": 104,
  "order_product" : @"Product#1",
  "order_price" : 12.95
}

@interface OrderModel : JSONModel
@property (assign, nonatomic) int orderId;
@property (assign, nonatomic) float orderPrice;
@property (strong, nonatomic) NSString* orderProduct;
@end
@implementation OrderModel
+(JSONKeyMapper*)keyMapper
{
return [JSONKeyMapper mapperFromUnderscoreCaseToCamelCase];
}
@end

Optional properties (i.e. can be missing or null)

{
  "id": "123",
  "name": null,
  "price": 12.95
}

@interface ProductModel : JSONModel
@property (assign, nonatomic) int id;
@property (strong, nonatomic) NSString<Optional>* name;
@property (assign, nonatomic) float price;
@property (strong, nonatomic) NSNumber<Optional>* uuid;
@end
@implementation ProductModel
@end

Ignored properties (i.e. JSONModel completely ignores them)

{
  "id": "123",
  "name": null
}

@interface ProductModel : JSONModel
@property (assign, nonatomic) int id;
@property (strong, nonatomic) NSString<Ignore>* customProperty;
@end
@implementation ProductModel
@end

Make all model properties optional (avoid if possible)

@implementation ProductModel
+(BOOL)propertyIsOptional:(NSString*)propertyName
{
  return YES;
}
@end

Lazy convert collection items from dictionaries to models

{
  "order_id": 104,
  "total_price": 103.45,
  "products" : [
    {
      "id": "123",
      "name": "Product #1",
      "price": 12.95
    },
    {
      "id": "137",
      "name": "Product #2",
      "price": 82.95
    }
  ]
}

@protocol ProductModel
@end
@interface ProductModel : JSONModel
@property (assign, nonatomic) int id;
@property (strong, nonatomic) NSString* name;
@property (assign, nonatomic) float price;
@end
@implementation ProductModel
@end
@interface OrderModel : JSONModel
@property (assign, nonatomic) int order_id;
@property (assign, nonatomic) float total_price;
@property (strong, nonatomic) NSArray<ProductModel, ConvertOnDemand>* products;
@end
@implementation OrderModel
@end

Using the built-in thin HTTP client

//add extra headers
[[JSONHTTPClient requestHeaders] setValue:@"MySecret" forKey:@"AuthorizationToken"];

//make post, get requests
[JSONHTTPClient postJSONFromURLWithString:@"http://mydomain.com/api"
                                   params:@{@"postParam1":@"value1"}
                               completion:^(id json, JSONModelError *err) {
                                   
                                   //check err, process json ...
                                   
                               }];

Export model to NSDictionary or to JSON text

ProductModel* pm = [[ProductModel alloc] initWithString:jsonString error:nil];
pm.name = @"Changed Name";

//convert to dictionary
NSDictionary* dict = [pm toDictionary];

//convert to text
NSString* string = [pm toJSONString];

json validation
data transformations
error handling
custom data validation
automatic compare and equality features
and more.

Misc

Author: Marin Todorov

Contributors: Christian Hoffmann, Mark Joslin, Julien Vignali, Symvaro GmbH, BB9z. Also everyone who did successful pull requests.

Change log : https://github.com/icanzilb/JSONModel/blob/master/Changelog.md

License

This code is distributed under the terms and conditions of the MIT license.

Contribution guidelines

NB! If you are fixing a bug you discovered, please add also a unit test so I know how exactly to reproduce the bug before merging.

cknadler/JSONModel