These set of files are intended to demonstrate a typical MVC architecture and how data flows between the different layers. Code snippet for Service class goes here.

UserProfileService.m

//
//  ProfileService.h
//  Project A
//
//  Created by Company A on 7/25/13.
//  Copyright (c) 2013 Company A. All rights reserved.
//

#import <Foundation/Foundation.h>
#import "UserProfile.h"
#import "ASIHTTPRequest.h"

@protocol UserProfileServiceDelegate <NSObject>
@optional

-(void)didReceiveCreateProfileResponseWithCode:(int)code error:(NSString*)error;
-(void)didReceiveGetProfileResponseWithCode:(UserProfile*)profile error:(NSString*)error;
-(void)didReceiveUpdateProfileResponseWithCode:(UserProfile*)profile error:(NSString*)error;

@end

@interface UserProfileService : NSObject
{
     ASIHTTPRequest *asiHTTPRequest;
     UserProfile *userProfile;
}

@property (nonatomic, strong) id<UserProfileServiceDelegate>delegate;

// method to create a new user profile
-(void)createProfile:(UserProfile*)profile;

// method to retreive an existing user profile with userId
-(void)getProfileForId:(int)userId;

// method to update the user profile
-(void)updateProfile:(UserProfile*)profile;

@end



//
//  ProfileService.m
//  Project A
//
//  Created by Company A on 7/25/13.
//  Copyright (c) 2013 Company A. All rights reserved.
//

#import "UserProfileService.h"

@implementation UserProfileService

@synthesize delegate;

- (id)init {
    self = [super init];
    
    return self;
}

-(void)buildRequestWithURL:(NSURL*)url Tag:(int)tag andMethod:(NSString*)methodType payload:(NSString*)payload
{
     asiHTTPRequest = [ASIHTTPRequest requestWithURL:url];
    [asiHTTPRequest setDelegate:self];
    [asiHTTPRequest setRequestMethod:methodType];
    [asiHTTPRequest setValidatesSecureCertificate:NO];
    [asiHTTPRequest setTimeOutSeconds:40.0];
    [asiHTTPRequest setTag:tag];
    [asiHTTPRequest addRequestHeader:@"Content-Type" value:@"application/json"];
    
    if (payload) {
        NSData *postBody=[payload dataUsingEncoding:NSUTF8StringEncoding];
        [asiHTTPRequest setPostBody:[NSMutableData dataWithData:postBody]];
    }
    
    [asiHTTPRequest startAsynchronous];
}

#pragma mark - ASIHTTP callbacks

- (void)requestFinished:(ASIHTTPRequest *)request
{
    if (request.tag == 1) {
        [self handleCreateProfileResponse:request];
    }
    if (request.tag == 2) {
        [self handleGetProfileResponse:request];
    }
    if (request.tag == 3) {
        [self handleUpdateProfileResponse:request];
    }
}

- (void)requestFailed:(ASIHTTPRequest *)request
{
    // Handle the service error
    NSError *error = [request error];
    NSLog(@"Service Error : %@",error);
    
    if (request.tag == 1) {
        if ([delegate respondsToSelector:@selector(didReceiveCreateProfileResponseWithCode:error:)]) {
            [delegate didReceiveCreateProfileResponseWithCode:0 error:error.localizedDescription];
        }
    }
    if (request.tag == 2) {
        if ([delegate respondsToSelector:@selector(didReceiveGetProfileResponseWithCode:error:)]) {
            [delegate didReceiveGetProfileResponseWithCode:0 error:error.localizedDescription];
        }
    }
    if (request.tag == 3) {
        if ([delegate respondsToSelector:@selector(didReceiveUpdateProfileResponseWithCode:error:)]) {
            [delegate didReceiveUpdateProfileResponseWithCode:0 error:error.localizedDescription];
        }
    }
}

#pragma mark - Create Profile

// Provide the following details in UserProfile Obj
// 1. emailId
// 2. username
// 3. password
-(void)createProfile:(UserProfile*)profile
{
    if ([CommonUtilities isConnectedToInternet]) {
        
        userProfile = [[UserProfile alloc]init];
        userProfile = profile;
        
        NSString *urlString = @"Service URL to create a profile";
        
        NSURL *url = [NSURL URLWithString:urlString];
        
        NSString *payload=[NSString stringWithFormat:@"{\"email_id\": %@,"
                           @"\"password\": %@,"
                           @"\"user_name\":%@}",
                           profile.email_id,
                           [CommonUtilities getMD5:profile.password],
                           profile.user_name];
        
        [self buildRequestWithURL:url Tag:1 andMethod:@"PUT" payload:payload];
    }
    else
    {
        // Handle offline use case
        NSLog(@"No internet connection");
        if ([delegate respondsToSelector:@selector(didReceiveCreateProfileResponseWithCode:error:)]) {
            [delegate didReceiveCreateProfileResponseWithCode:0 error:CONST_CHECK_INTERNET];
        }
    }
}

-(void)handleCreateProfileResponse:(ASIHTTPRequest*)request
{
    // Handle the response
    NSData *response = [request responseData];
    int reponseStatus = [request responseStatusCode];

    // pasring the JSON response
    NSError *error;
    NSMutableDictionary *resultDictionary = [NSJSONSerialization JSONObjectWithData:response options:kNilOptions error:&error];
    
    if (reponseStatus == 200) {
        // success
        UserProfile *userprofile = [[UserProfile alloc]initWithDictionary:resultDictionary];

        if ([delegate respondsToSelector:@selector(didReceiveCreateProfileResponseWithCode:error:)]) {
            [delegate didReceiveCreateProfileResponseWithCode:200 error:nil];
        }
    }
    else
    {
        // failure
        NSString *description = [resultDictionary objectForKey:@"status_description"];
        if ([delegate respondsToSelector:@selector(didReceiveCreateProfileResponseWithCode:error:)]) {
            [delegate didReceiveCreateProfileResponseWithCode:0 error:description];
        }
    }
}


#pragma mark - Get Profile

-(void)getProfileForId:(int)userId
{
    if ([CommonUtilities isConnectedToInternet]) {
        
        NSString *urlString = @"Service URL to get a profile";
        
        NSURL *url = [NSURL URLWithString:urlString];
        
        [self buildRequestWithURL:url Tag:2 andMethod:@"GET" payload:nil];
    }
    else
    {
        // Handle offline use case
        NSLog(@"No internet connection");
        if ([delegate respondsToSelector:@selector(didReceiveGetProfileResponseWithCode:error:)]) {
            [delegate didReceiveGetProfileResponseWithCode:0 error:CONST_CHECK_INTERNET];
        }
    }
}

-(void)handleGetProfileResponse:(ASIHTTPRequest*)request
{
    // Handle the response
    NSData *response = [request responseData];
    int reponseStatus = [request responseStatusCode];
    
    // pasring the JSON response
    NSError *error;
    NSMutableDictionary *resultDictionary = [NSJSONSerialization JSONObjectWithData:response options:kNilOptions error:&error];
    
    if (reponseStatus == 200) {
        // success
        UserProfile *userprofile = [[UserProfile alloc]initWithDictionary:resultDictionary];

        if ([delegate respondsToSelector:@selector(didReceiveGetProfileResponseWithCode:error:)]) {
            [delegate didReceiveGetProfileResponseWithCode:userprofile error:nil];
        }
    }
    else
    {
        // failure
        NSString *description = [resultDictionary objectForKey:@"status_description"];
        if ([delegate respondsToSelector:@selector(didReceiveGetProfileResponseWithCode:error:)]) {
            [delegate didReceiveGetProfileResponseWithCode:0 error:description];
        }
    }
}


#pragma mark - Update Profile
// Provide the updated details in UserProfile Obj

-(void)updateProfile:(UserProfile*)profile
{
    if ([CommonUtilities isConnectedToInternet]) {
        
        userProfile = [[UserProfile alloc]init];
        userProfile = profile;
        
        NSString *urlString =  @"Service URL to update a profile";
        
        NSURL *url = [NSURL URLWithString:urlString];
        
        NSString *payload=[NSString stringWithFormat:@"{\"abt_me\": %@,"
                           @"\"email_id\": %@,"
                           @"\"id\": %@,"
                           @"\"location\": %@,"
                           @"\"image\": %@,"
                           @"\"password\": %@,"
                           @"\"user_name\":%@}",
                           profile.abt_me,
                           profile.email_id,
                           profile.id,
                           profile.location,
                           profile.image,
                           profile.password,
                           profile.user_name];
        
        [self buildRequestWithURL:url Tag:3 andMethod:@"POST" payload:payload];
    }
    else
    {
        // Handle offline use case
        NSLog(@"No internet connection");
        if ([delegate respondsToSelector:@selector(didReceiveUpdateProfileResponseWithCode:error:)]) {
            [delegate didReceiveUpdateProfileResponseWithCode:0 error:CONST_CHECK_INTERNET];
        }
    }
}

-(void)handleUpdateProfileResponse:(ASIHTTPRequest*)request
{
    // Handle the response
    NSData *response = [request responseData];
    int reponseStatus = [request responseStatusCode];
    
    // pasring the JSON response
    NSError *error;
    NSMutableDictionary *resultDictionary = [NSJSONSerialization JSONObjectWithData:response options:kNilOptions error:&error];
    
    if (reponseStatus == 200) {
        // success
        UserProfile *userprofile = [[UserProfile alloc]initWithDictionary:resultDictionary];
        
        if ([delegate respondsToSelector:@selector(didReceiveUpdateProfileResponseWithCode:error:)]) {
            [delegate didReceiveUpdateProfileResponseWithCode:userprofile error:nil];
        }
    }
    else
    {
        // failure
        NSString *description = [resultDictionary objectForKey:@"status_description"];
        if ([delegate respondsToSelector:@selector(didReceiveUpdateProfileResponseWithCode:error:)]) {
            [delegate didReceiveUpdateProfileResponseWithCode:0 error:description];
        }
    }
}

@end