Designer News API iOS Wrapper. Full Source Code can be found at https://github.com/TosinAF/thenews

A-DN-API-iOS-Wrapper-Readme.md

I released TheNews iOS (bit.ly/thenews-ios) over the past summer. A required part of the app was to communicate with the designer news api. The api had only just been recently released so there was no wrapper for iOS apps.

As such, I had to create an API wrapper. Having never attempted this before, I studied a few examples on Github and modeled my solution like those I had seen.

It was a really interesting project to build. It's important to create the wrapper as a singleton to maintain a user session & prevent multiple calls of the same requests. I also built the wrapper with the consideration that others might find it useful (https://github.com/TosinAF/DNManager) .

As such I had to consider what methods should be public and make them easy for anyone to get familiar with it.

I leveraged the power of the AFNetworking Library to build the api wrapper & used blocks so as to allow the user to specify what actions should be taken if the request succeeds or if it fails.

API Spec can be found at http://developers.news.layervault.com/

DesignerNewsAPIClient.h

//
//  DesignerNewsAPIClient.h
//  DesignerNewsAPI
//
//  Created by Tosin Afolabi on 21/03/2014.
//  Copyright (c) 2014 Tosin Afolabi. All rights reserved.
//

#import "DNMOTD.h"
#import "DNUser.h"
#import "DNStory.h"
#import "DNComment.h"
#import "AFHTTPSessionManager.h"

typedef NS_ENUM (NSInteger, DNFeedType) {
	DNFeedTypeTop,
	DNFeedTypeRecent
};

typedef NS_ENUM (NSInteger, DNActionType) {
	DNActionTypeUpvote,
	DNActionTypeReply,
};

typedef NS_ENUM (NSInteger, DNObjectType) {
	DNObjectTypeStory,
	DNObjectTypeComment,
};

typedef void (^ActionSuccessBlock) ();
typedef void (^RequestFailureBlock) (NSURLSessionDataTask *task, NSError *error);

@interface DNManager : AFHTTPSessionManager

#pragma mark - Singleton Method

+ (instancetype)sharedManager;

#pragma mark - Authentication methods

- (void)authenticateUser:(NSString *)username
                password:(NSString *)password
                 success:(void (^) (NSString *accessToken))success
                 failure:(RequestFailureBlock)failure;

- (BOOL)isUserAuthenticated;

- (void)logout;

#pragma mark - DN User Methods

- (void)getUserInfo:(void (^) (DNUser *userInfo))success
            failure:(RequestFailureBlock)failure;

#pragma mark - DN Search Methods

- (void)search:(NSString *)searchQuery
         success:(void (^) (NSArray *dnStories))success
         failure:(RequestFailureBlock)failure;

#pragma mark - DN Story Methods

- (void)getStoriesOnPage:(NSString *)page
                feedType:(DNFeedType)feedType
                 success:(void (^) (NSArray *dnStories))success
                 failure:(RequestFailureBlock)failure;

- (void)getStoryWithID:(NSString *)storyID
               success:(void (^) (DNStory *story))success
               failure:(RequestFailureBlock)failure;

- (void)upvoteStoryWithID:(NSString *)storyID
                  success:(ActionSuccessBlock)success
                  failure:(RequestFailureBlock)failure;


- (void)replyStoryWithID:(NSString *)storyID
                 comment:(NSString *)comment
                 success:(ActionSuccessBlock)success
                 failure:(RequestFailureBlock)failure;

- (void)addStoryToReadList:(NSNumber *)storyID;

- (BOOL)hasUserReadStory:(NSNumber *)storyID;

#pragma mark - DN Comment Methods

- (void)getCommentsForStoryWithID:(NSString *)storyID
                          success:(void (^) (NSArray *comments))success
                          failure:(RequestFailureBlock)failure;

- (void)upvoteCommentWithID:(NSString *)commentID
                    success:(ActionSuccessBlock)success
                    failure:(RequestFailureBlock)failure;

- (void)replyCommentWithID:(NSString *)commentID
                   comment:(NSString *)comment
                   success:(ActionSuccessBlock)success
                   failure:(RequestFailureBlock)failure;

#pragma mark - DN MOTD Methods

- (void)getMOTD:(void (^) (DNMOTD *motd))success
        failure:(RequestFailureBlock)failure;

- (void)upvoteMOTD:(void (^) (NSURLSessionDataTask *task, id responseObject))success
           failure:(RequestFailureBlock)failure;

- (void)downvoteMOTD:(void (^) (NSURLSessionDataTask *task, id responseObject))success
             failure:(RequestFailureBlock)failure;

#pragma mark - Auxillary Methods

- (void)cancelAllRequests;

@end

DesignerNewsAPIClient.m

//
//  DesignerNewsAPIClient.m
//  DesignerNewsAPI
//
//  Created by Tosin Afolabi on 21/03/2014.
//  Copyright (c) 2014 Tosin Afolabi. All rights reserved.
//


#import "DNManager.h"

static NSString * const DNAPIAccessTokenKey     = @"DNAPIAccessTokenKey";
static NSString * const DNReadPostsKey          = @"DNReadPostsKey";
static NSString * const DNReadPostsCacheDateKey = @"DNReadPostsCacheDateKey";
static NSString * const DNAPIBaseURLString      = @"https://api-news.layervault.com/api/v1";
static NSString * const DNAPIClientID           = @"";
static NSString * const DNAPIClientSecret       = @"";

@interface DNManager ()

@property (nonatomic, strong) NSMutableArray *allCommentsForStory;

@end

@implementation DNManager


#pragma mark - Singleton Method

+ (instancetype)sharedManager {

    static DNManager *_sharedClient = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        _sharedClient = [[DNManager alloc] initWithBaseURL:[NSURL URLWithString:DNAPIBaseURLString]];
    });

    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];

    if([defaults arrayForKey:DNReadPostsKey] == nil) {
        [defaults setObject:[NSArray new] forKey:DNReadPostsKey];
        [defaults synchronize];
    }

    [_sharedClient checkReadPostsCache];

    return _sharedClient;
}

#pragma mark - Authentication methods

- (void)authenticateUser:(NSString *)username
                password:(NSString *)password
                 success:(void (^) (NSString *accessToken))success
                 failure:(RequestFailureBlock)failure
{
    NSString *authURL = @"https://api-news.layervault.com/oauth/token";
    NSDictionary *parameters = @{@"grant_type" : @"password",
                                 @"username" : username,
                                 @"password" : password,
                                 @"client_id": DNAPIClientID,
                                 @"client_secret" : DNAPIClientSecret };

    [self POST:authURL parameters:parameters success:^(NSURLSessionDataTask *task, id responseObject) {
        NSString *accessToken = responseObject[@"access_token"];

        // Store Access Token
        NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
        [defaults setObject:accessToken forKey:DNAPIAccessTokenKey];
        [defaults synchronize];

        success(accessToken);

    } failure:failure];
}

- (BOOL)isUserAuthenticated
{
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    NSString *accessToken = [defaults objectForKey:DNAPIAccessTokenKey];

    if ( accessToken == Nil ) {
        return false;
    }
    return true;
}

- (void)logout
{
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    [defaults setObject:nil forKey:DNAPIAccessTokenKey];
    [defaults synchronize];
}

#pragma mark - DN User Methods

- (void)getUserInfo:(void (^) (DNUser *userInfo))success
            failure:(RequestFailureBlock)failure
{
    NSString *resourceURL = [NSString stringWithFormat:@"%@/me", DNAPIBaseURLString];

    NSString *accessToken = [self getAccessToken];
    [self.requestSerializer setValue:[NSString stringWithFormat:@"Bearer %@", accessToken] forHTTPHeaderField:@"Authorization"];

    [self GET:resourceURL parameters:nil success:^(NSURLSessionDataTask *task, id responseObject) {

        DNUser *userInfo = [[DNUser alloc] initWithDictionary:responseObject[@"user"]];
        success(userInfo);

    } failure:failure];
}

#pragma mark - DN Search Methods

- (void)search:(NSString *)searchQuery
         success:(void (^) (NSArray *dnStories))success
         failure:(RequestFailureBlock)failure
{
    NSMutableArray *stories = [NSMutableArray new];

    NSString *resourceURL = [NSString stringWithFormat:@"%@/stories/search", DNAPIBaseURLString];
    NSDictionary *parameters = @{@"query":searchQuery, @"client_id":DNAPIClientID};
    NSLog(@"%@", resourceURL);

    [self GET:resourceURL parameters:parameters success:^(NSURLSessionDataTask *task, id responseObject) {



        for (NSDictionary *story in responseObject) {
            [stories addObject:[[DNStory alloc] initWithDictionaryForSearch:story]];
        }

        success([NSArray arrayWithArray:stories]);
        
    } failure:failure];
}

#pragma mark - DN Story Methods


- (void)getStoriesOnPage:(NSString *)page
                feedType:(DNFeedType)feedType
                 success:(void (^) (NSArray *dnStories))success
                 failure:(RequestFailureBlock)failure

{
    NSString *resourceURL;

    switch (feedType) {

        case DNFeedTypeTop:
        default:
            resourceURL = [NSString stringWithFormat:@"%@/stories", DNAPIBaseURLString];
            break;

        case DNFeedTypeRecent:
            resourceURL = [NSString stringWithFormat:@"%@/stories/recent", DNAPIBaseURLString];
            break;
    }

    NSDictionary *parameters = @{@"page":page, @"client_id": DNAPIClientID};

    [self getStories:resourceURL parameters:parameters success:success failure:failure];
}

- (void)getStoryWithID:(NSString *)storyID
                success:(void (^) (DNStory *story))success
                failure:(RequestFailureBlock)failure
{
    NSString *resourceURL = [NSString stringWithFormat:@"%@/stories/%@", DNAPIBaseURLString, storyID];
    NSDictionary *parameters = @{@"client_id": DNAPIClientID};

    [self GET:resourceURL parameters:parameters success:^(NSURLSessionDataTask *task, id responseObject) {

        DNStory *story = [[DNStory alloc] initWithDictionary:responseObject[@"story"]];
        success(story);

    } failure:failure];

}

- (void)upvoteStoryWithID:(NSString *)storyID
                  success:(ActionSuccessBlock)success
                  failure:(RequestFailureBlock)failure
{
    [self performActionOnObjectWithID:storyID
                               object:DNObjectTypeStory
                               action:DNActionTypeUpvote
                              comment:nil
                              success:success
                              failure:failure];
}

- (void)replyStoryWithID:(NSString *)storyID
                 comment:(NSString *)comment
                 success:(ActionSuccessBlock)success
                 failure:(RequestFailureBlock)failure
{
    [self performActionOnObjectWithID:storyID
                               object:DNObjectTypeStory
                               action:DNActionTypeReply
                              comment:comment
                              success:success
                              failure:failure];
}

- (void)addStoryToReadList:(NSNumber *)storyID
{
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    NSArray *currentReadArticles = [defaults arrayForKey:DNReadPostsKey];

    if ([self hasUserReadStory:storyID]) {
        return;
    }

    NSMutableArray *newReadArticles = [NSMutableArray arrayWithArray:currentReadArticles];
    [newReadArticles addObject:storyID];

    [defaults setObject:[NSArray arrayWithArray:newReadArticles] forKey:DNReadPostsKey];
    [defaults synchronize];
}

- (BOOL)hasUserReadStory:(NSNumber *)storyID
{
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    NSArray *currentReadArticles = [defaults arrayForKey:DNReadPostsKey];

    return [currentReadArticles containsObject:storyID];
}

- (void)checkReadPostsCache
{
    NSDate *cacheDate = [[NSUserDefaults standardUserDefaults] objectForKey:DNReadPostsCacheDateKey];
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];

    //  If this is the first time the app has been launched we record right now as the first time the app was launched.
    if (!cacheDate) {
        [defaults setObject:[NSDate date] forKey:DNReadPostsCacheDateKey];
        return;
    }

    int diff = abs([cacheDate timeIntervalSinceNow]);
    if (diff > 60 * 60 * 24 * 3) {
        [defaults setObject:[NSArray new] forKey:DNReadPostsKey];
    }
}

#pragma mark - DN Comment Methods

- (void)getCommentsForStoryWithID:(NSString *)storyID
                          success:(void (^) (NSArray *comments))success
                          failure:(RequestFailureBlock)failure
{
    NSString *resourceURL = [NSString stringWithFormat:@"%@/stories/%@", DNAPIBaseURLString, storyID];
    NSDictionary *parameters = @{@"client_id": DNAPIClientID};

    self.allCommentsForStory = [[NSMutableArray alloc] init];

    [self GET:resourceURL parameters:parameters success:^(NSURLSessionDataTask *task, id responseObject) {

        [self collapseNestedComments:[responseObject[@"story"] objectForKey:@"comments"]];
        success([NSArray arrayWithArray:self.allCommentsForStory]);
        self.allCommentsForStory = nil;

    } failure:failure];
}

- (void)upvoteCommentWithID:(NSString *)commentID
                  success:(ActionSuccessBlock)success
                  failure:(RequestFailureBlock)failure
{
    [self performActionOnObjectWithID:commentID
                               object:DNObjectTypeComment
                               action:DNActionTypeUpvote
                              comment:nil
                              success:success
                              failure:failure];
}



- (void)replyCommentWithID:(NSString *)commentID
                   comment:(NSString *)comment
                   success:(ActionSuccessBlock)success
                   failure:(RequestFailureBlock)failure
{
    [self performActionOnObjectWithID:commentID
                               object:DNObjectTypeComment
                               action:DNActionTypeReply
                              comment:comment
                              success:success
                              failure:failure];
}

#pragma mark - DN MOTD Methods

- (void)getMOTD:(void (^) (DNMOTD *motd))success
        failure:(RequestFailureBlock)failure
{
    NSString *resourceURL = [NSString stringWithFormat:@"%@/motd", DNAPIBaseURLString];
    NSDictionary *parameters = @{@"client_id": DNAPIClientID};

    [self GET:resourceURL parameters:parameters success:^(NSURLSessionDataTask *task, id responseObject) {

        DNMOTD *motd = [[DNMOTD alloc] initWithDictionary:responseObject[@"motd"]];
        success(motd);

    } failure:failure];
}

- (void)upvoteMOTD:(void (^) (NSURLSessionDataTask *task, id responseObject))success
           failure:(RequestFailureBlock)failure
{
    [self performActionOnMOTD:@"upvote" success:success failure:failure];
}

- (void)downvoteMOTD:(void (^) (NSURLSessionDataTask *task, id responseObject))success
             failure:(RequestFailureBlock)failure
{
    [self performActionOnMOTD:@"downvote" success:success failure:failure];
}

#pragma mark - Auxillary Methods

- (void)cancelAllRequests
{
    [self.operationQueue cancelAllOperations];
}

#pragma mark - Private Methods

- (NSString *)getAccessToken
{
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    NSString *accessToken = [defaults objectForKey:DNAPIAccessTokenKey];

    return accessToken;
}

- (void)getStories:(NSString *)resourceURL
        parameters:(NSDictionary *)parameters
           success:(void (^) (NSArray *dnStories))success
           failure:(RequestFailureBlock)failure

{
    NSMutableArray *stories = [NSMutableArray new];

    [self GET:resourceURL parameters:parameters success:^(NSURLSessionDataTask *task, id responseObject) {

        for (NSDictionary *story in responseObject[@"stories"]) {
            [stories addObject:[[DNStory alloc] initWithDictionary:story]];
        }

        success([NSArray arrayWithArray:stories]);

    } failure:failure];
}

- (void)performActionOnObjectWithID:(NSString *)objectID
                             object:(DNObjectType)objectType
                             action:(DNActionType)actionType
                            comment:(NSString *)comment
                            success:(ActionSuccessBlock)success
                            failure:(RequestFailureBlock)failure
{
    NSString *object, *action;

    switch (objectType) {
        case DNObjectTypeStory:
            object = @"stories";
            break;

        case DNObjectTypeComment:
            object = @"comments";

            break;
    }

    switch (actionType) {
        case DNActionTypeUpvote:
            action = @"upvote";
            break;

        case DNActionTypeReply:
            action = @"reply";
            break;
    }

    NSString *resourceURL = [NSString stringWithFormat:@"%@/%@/%@/%@", DNAPIBaseURLString, object, objectID, action];
    NSLog(@"%@", resourceURL);

    NSString *accessToken = [self getAccessToken];
    [self.requestSerializer setValue:[NSString stringWithFormat:@"Bearer %@", accessToken] forHTTPHeaderField:@"Authorization"];


    if (actionType == DNActionTypeReply) {

        [self POST:resourceURL parameters:nil constructingBodyWithBlock:^(id<AFMultipartFormData> formData) {
            [formData appendPartWithFormData:[comment dataUsingEncoding:NSUTF8StringEncoding] name:@"comment[body]"];
        } success:^(NSURLSessionDataTask *task, id responseObject) {
            success();
        } failure:failure];

    } else {

        [self POST:resourceURL parameters:nil success:^(NSURLSessionDataTask *task, id responseObject) {
            success();
        } failure:failure];
    }
}

- (void)performActionOnMOTD:(NSString *)actionType
                    success:(void (^) (NSURLSessionDataTask *task, id responseObject))success
                    failure:(RequestFailureBlock)failure
{

    NSString *resourceURL = [NSString stringWithFormat:@"%@/motd/%@", DNAPIBaseURLString, actionType];

    NSString *accessToken = [self getAccessToken];
    [self.requestSerializer setValue:[NSString stringWithFormat:@"Bearer %@", accessToken] forHTTPHeaderField:@"Authorization"];

    [self POST:resourceURL parameters:nil success:success failure:failure];
}

- (void)collapseNestedComments:(NSDictionary*)dict {

    for (id comment in dict) {

        DNComment *x = [[DNComment alloc] initWithDictionary:comment];
        [self.allCommentsForStory addObject:x];

        if (comment[@"comments"] != Nil) {
            [self collapseNestedComments:comment[@"comments"]];
        }
    }
    
    return;
}

@end