Small library that parse JSON and map it to any object, works with NSManagedObject.

Example object interface

@interface User : NSObject

@property (nonatomic, strong) NSNumber *userID;
@property (nonatomic, strong) NSString *firstName;
@property (nonatomic, strong) NSDate *createdAt;

@end

Mapping

[BWObjectMapping mappingForObject:[User class] block:^(BWObjectMapping *mapping) {
    [mapping mapPrimaryKeyAttribute:@"id" toAttribute:@"userID"];
    [mapping mapKeyPath:@"first_name" toAttribute:@"firstName"];
    [mapping mapKeyPath:@"created_at" toAttribute:@"createdAt"];                
    [[BWObjectMapper shared] registerMapping:mapping withRootKeyPath:@"user"];
}];

At the last line we register the mapping and give a root key path. You don't need to have one, but if not the mapper will not be able to guess which mapping class to use.

Object creation

[[BWObjectMapper shared] objectWithBlock:^id(Class objectClass, NSString *primaryKey, id primaryKeyValue, id JSON) {
    return [[objectClass alloc] init];
}];

The json

{
    "user": [{
        "id": 1,
        "first_name": "Bruno",
        "created_at": "2012-08-10T06:12:28Z"
    }]
}

Default parsing date format is Rails format.

Map json to object

NSArray *objects = [[BWObjectMapper shared] objectsFromJSON:JSON];

Because the JSON contain a root key path, the mapping automatically discover.

All mapping methods

- (NSArray *)objectsFromJSON:(id)JSON withMapping:(BWObjectMapping *)mapping;

- (NSArray *)objectsFromJSON:(id)JSON withObjectClass:(Class)objectClass;

- (NSArray *)objectsFromJSON:(id)JSON;

- (id)objectFromJSON:(id)JSON withMapping:(BWObjectMapping *)mapping;

- (id)objectFromJSON:(id)JSON withMapping:(BWObjectMapping *)mapping existingObject:(id)object;

- (id)objectFromJSON:(id)JSON withObjectClass:(Class)objectClass;

- (id)objectFromJSON:(id)JSON withObjectClass:(Class)objectClass existingObject:(id)object;

- (id)objectFromJSON:(id)JSON;

- (id)objectFromJSON:(id)JSON existingObject:(id)object;

Note about date format

If you don't use Rails date format you have two options:

1. Specify global date format

   [objectMapping mapKeyPath:@"created_at" toAttribute:@"createdAt" dateFormat:@""];

2. Custom date format on each attribute.

   [[BWObjectMapper shared] setDefaultDateFormat:@""];

Installation

Copy BWObjectMapper dir into your project.

ARC

BWObjectMapper is ARC only.

Todo

• Handle relation (Has many, has one, …)

Contact

Bruno Wernimont

• Twitter - @brunowernimont