Catalytic 1.0.2

You want to add pod 'Catalytic', '~> 1.0' similar to the following to your Podfile:

target 'MyApp' do
  pod 'Catalytic', '~> 1.0'
end

Then run a pod install inside your terminal, or from CocoaPods.app.

Alternatively to give it a test run, run the command:

pod try Catalytic

Catalytic 1.0.2

By
Patrick Hogan

This library is deprecated.

What is Catalytic?

Catalytic provides a simple way to map JSON data onto native Objective-C domain objects.

Requirements

iOS 9.0+ / Mac OS X 10.10+
Xcode 7.0
Cocoapods 0.37.1

Usage

Consider the following examples of domain objects, ModelObject and NestedObject.

//  ModelObject.h

#import <Foundation/Foundation.h>

@class NestedObject;

@interface ModelObject : NSObject

@property (nonatomic, readonly) NSArray<NSString *> *strings;
@property (nonatomic, readonly) NestedObject *nestedObject;
@property (nonatomic, readonly) NSArray<NestedObject *> *nestedObjects;

@end

//  NestedObject.h

#import <Foundation/Foundation.h>

@interface NestedObject : NSObject

@property (nonatomic, readonly, copy) NSString *string;
@property (nonatomic, readonly) NSInteger integer;

@end

Catalytic can easily map the corresponding JSON representation of these objects onto the native fields given above.

{
    "type": "model_object",
    "nested_object": {
        "type": "nested_object",
        "string": "0",
        "integer": 0
    },
    "nested_objects": [
        {
            "type": "nested_object",
            "string": "1",
            "integer": 1
        },
        {
            "type": "nested_object",
            "string": "2",
            "integer": 2
        }
    ],
    "strings": [
        "abc",
        "bbd"
    ]
}

First set up a id <CTTypeProvider> instance to handle the mapping of contained dictionaries to domain object classes.

//  TypeProvider.m

#import "TypeProvider.h"

#import "ModelObject.h"
#import "NestedObject.h"

@implementation TypeProvider

- (Class)typeOfObject:(id)object
       containerClass:(__unsafe_unretained Class)containerClass
       referencingKey:(NSString *)key
            fieldType:(CTConverterFieldType)fieldType {

    if ([[object valueForKey:@"type"] isEqualToString:@"model_object"]) {
        return [ModelObject class];
    } else if ([[object valueForKey:@"type"] isEqualToString:@"nested_object"]) {
        return [NestedObject class];
    } else {
        return NULL;
    }

}

@end

Then it is a straightforward exercise to recover a parsed domain object from the given JSON.

id <CTTypeProvider> typeProvider = [[TypeProvider alloc] init];
CTConverter *converter = [[CTConverter alloc] initWithFieldNamingPolicy:CTConverterFieldNamingPolicyLowerCaseWithUnderscores
                                                           typeProvider:typeProvider];

NSDictionary *jsonDictionary = ({
    NSString *jsonPath = [[NSBundle mainBundle] pathForResource:@"model_object" ofType:@"json"];
    NSData *jsonData = [[NSData alloc] initWithContentsOfFile:jsonPath];
    [NSJSONSerialization JSONObjectWithData:jsonData options:kNilOptions error:nil];
});

NSError * __autoreleasing error;
ModelObject *modelObject = [converter convert:jsonDictionary error:&error];