NSRails 的なクラスを自前で作ってみた ref: http://qiita.com/items/dc8d46a1da1e13efefe5

file0.txt

{
    "meta": {
        "limit": 20, 
        "next": null, 
        "offset": 0, 
        "previous": null, 
        "total_count": 3
    }, 
    "objects": [
        {
            "id": 2, 
            "name": "カフェ", 
            "resource_uri": "/api/tag/%E3%82%AB%E3%83%95%E3%82%A7", 
            "slug": "カフェ"
        }, 
        {
            "id": 1, 
            "name": "ハッカソン", 
            "resource_uri": "/api/tag/%E3%83%8F%E3%83%83%E3%82%AB%E3%82%BD%E3%83%B3", 
            "slug": "ハッカソン"
        }, 
        {
            "id": 3, 
            "name": "破滅", 
            "resource_uri": "/api/tag/%E7%A0%B4%E6%BB%85", 
            "slug": "破滅"
        }
    ]
}

JSON

{
    "meta": {
        "limit": 20, 
        "next": null, 
        "offset": 0, 
        "previous": null, 
        "total_count": 3
    }, 
    "objects": [
        {
            "id": 2, 
            "name": "カフェ", 
            "resource_uri": "/api/tag/%E3%82%AB%E3%83%95%E3%82%A7", 
            "slug": "カフェ"
        }, 
        {
            "id": 1, 
            "name": "ハッカソン", 
            "resource_uri": "/api/tag/%E3%83%8F%E3%83%83%E3%82%AB%E3%82%BD%E3%83%B3", 
            "slug": "ハッカソン"
        }, 
        {
            "id": 3, 
            "name": "破滅", 
            "resource_uri": "/api/tag/%E7%A0%B4%E6%BB%85", 
            "slug": "破滅"
        }
    ]
}

MMAppDelegate.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    [MMRemoteConfig defaultConfig].baseurl = @"http://example.net/api/";
;
    return YES;
}

MMRemoteClass.h

//
//  MMRemoteClass.h
//  MoyaMap
//
//  Created by Haruyuki Seki on 2/16/13.
//  Copyright (c) 2013 Hacker's Cafe. All rights reserved.
//
#import <Foundation/Foundation.h>

// bloc definition
typedef void(^MMFetchCompletionBlock)(NSArray *allRemote, NSError *error);

@interface MMRemoteClass : NSObject
@property (nonatomic, strong) NSNumber* remoteId; // id property of remote class

/*
 // read JSON data from server and call block with NSArray of instanced Classes.
 */
+(void)fetchAsync:(MMFetchCompletionBlock)completionBlock;

/*
 // you should override below methods on a subclass
 */
+(NSString *)representUrl;
+(NSString *)resultKey;

@end

MMRemoteClass.m

//
//  MMRemoteClass.m
//  MoyaMap
//
//  Created by Haruyuki Seki on 2/16/13.
//  Copyright (c) 2013 Hacker's Cafe. All rights reserved.
//
#import <objc/runtime.h>

#import "MMRemoteClass.h"
#import "MMRemoteConfig.h"
#import "AFNetworking.h"
#import "MMPropertyUtil.h"

@implementation MMRemoteClass

/**
 // read data from specified URI
 */
+(void)fetchAsync:(MMFetchCompletionBlock)completionBlock{
    // create url
    NSString *strurl = [NSString stringWithFormat:@"%@%@", [MMRemoteConfig defaultConfig].baseurl, [[self class] performSelector:@selector(representUrl)]];

    NSLog(@"call:%@", strurl);
    NSURL *url = [NSURL URLWithString:strurl];
    // call URL
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    AFJSONRequestOperation *operation = [AFJSONRequestOperation JSONRequestOperationWithRequest:request success:^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON) {
        NSLog(@"App.net Global Stream: %@", JSON);
        // set parsed objects to NSArray
        NSArray *ret = [[self class] parseJSONArray:[JSON valueForKeyPath:[[self class] performSelector:@selector(resultKey)]]];
        // call block method
        completionBlock(ret,nil);
    } failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error, id JSON) {
        NSLog(@"App.net Error: %@", [error localizedDescription]);
        // error handling
        completionBlock(nil,error);
    }];
    [operation start];

}
#pragma mark -
#pragma mark internal method
/**
 // parse JSONArray and create class instance
 */
+(NSArray *)parseJSONArray:(NSArray *)array{
    NSMutableArray *ret = [NSMutableArray arrayWithCapacity:[array count]];
    for (NSDictionary *dict in array){
        id obj = [[[self class] alloc] init];
        [obj performSelector:@selector(setPropertiesUsingRemoteDictionary:) withObject:dict];
        [ret addObject:obj];
    }
    return [[NSArray alloc] initWithArray:ret];
}
/*
 // set property from JSON dictionary
 */
- (void) setPropertiesUsingRemoteDictionary:(NSDictionary *)dict
{
    if ([dict objectForKey:@"id"]){
        self.remoteId = [dict objectForKey:@"id"];
    }
    NSDictionary *props = [MMPropertyUtil classPropsFor:[self class]];
    for (NSString *key in [props allKeys]){
        NSLog(@"key:%@", key);
        if ([dict objectForKey:key]){
            [self setValue:[dict objectForKey:key] forKey:key];
        }
    }

}

#pragma mark -
#pragma mark below methods shoul be doverride in a subclass
+(NSString *)representUrl{
    [self doesNotRecognizeSelector:_cmd];
    return nil;
}
+(NSString *)resultKey{
    [self doesNotRecognizeSelector:_cmd];
    return nil;
}

@end

MMRemoteConfig.h

//
//  MMRemoteConfig.h
//  MoyaMap
//
//  Created by Haruyuki Seki on 2/16/13.
//  Copyright (c) 2013 Hacker's Cafe. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface MMRemoteConfig : NSObject
@property(nonatomic,strong) NSString *baseurl;

+ (MMRemoteConfig *) defaultConfig;
@end

MMRemoteConfig.m

//
//  MMRemoteConfig.m
//  MoyaMap
//
//  usage:
//    [MMRemoteConfig defaultConfig].baseurl = @"http://example.net/api/";
//
//  Created by Haruyuki Seki on 2/16/13.
//  Copyright (c) 2013 Hacker's Cafe. All rights reserved.
//

#import "MMRemoteConfig.h"

@implementation MMRemoteConfig
static MMRemoteConfig *defaultConfig = nil;

/*
 // singleton
 */
+ (MMRemoteConfig *) defaultConfig
{
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^
                  {
                      MMRemoteConfig  *newConfig = [[MMRemoteConfig  alloc] init];
                      [newConfig useAsDefault];
                  });

    return defaultConfig;
}

- (void) useAsDefault
{
    defaultConfig = self;
}

@end

MMTag.h

//
//  MMTag.h
//  MoyaMap
//
//  Created by Haruyuki Seki on 2/16/13.
//  Copyright (c) 2013 Hacker's Cafe. All rights reserved.
//
#import "MMRemoteClass.h"

@interface MMTag : MMRemoteClass
@property(nonatomic,retain) NSString *name;
@property(nonatomic,retain) NSString *resource_uri;
@property(nonatomic,retain) NSString *slug;
@end

MMTag.m

//
//  MMTag.m
//  MoyaMap
//
//  Created by Haruyuki Seki on 2/16/13.
//  Copyright (c) 2013 Hacker's Cafe. All rights reserved.
//

#import "MMTag.h"

@implementation MMTag

/*
 // baseurl に続くURL
 */
+(NSString *)representUrl{
    return @"tag";
}
/*
 // JSON 内の結果配列用キー
 */
+(NSString *)resultKey{
    return @"objects";
}
@end

MMViewController.m

- (void)viewDidLoad
{
    [super viewDidLoad];
    [MMTag fetchAsync:^(NSArray *allRemote, NSError *error) {
        // allRemote に MMTag の配列が入っているので好きなようにする
        if (!error){
            for (MMTag *tag in allRemote){
                NSLog(@"name is %@", tag.name);
            }
        }
    }];
}