- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Override point for customization after application launch.

    [DDModelHttpClient startWithURL:@"https://api.app.net/" delegate:self]; // initialzie a DDModelHttpClient

    return YES;
}

#pragma mark - DDHttpClient Delegate Method

- (NSDictionary *)encodeParameters:(NSDictionary *)params{

    // encode the the paramters
    NSMutableDictionary *finalParams = [NSMutableDictionary dictionaryWithDictionary:params];
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    formatter.dateFormat = @"yyyyMMddHHmmss";
    NSString *times = [formatter stringFromDate:[NSDate date]];
    [finalParams setObject:times forKey:@"time"];
    NSString *parameterString = [self ddEncode:finalParams];
    NSString *beforeSign = [NSString stringWithFormat:@"%@&%@&%@",PLATFORM,APP_KEY,parameterString];
    [finalParams setObject:[beforeSign md5] forKey:@"sign"];
    return finalParams;
}

- (NSString *)decodeResponseString:(NSString *)responseString{
    NSLog(@"responseString = %@",responseString);
    return responseString;
}

- (BOOL)checkResponseValueAvailable:(NSDictionary *)values
                            failure:(DDResponseFailureBlock)failure{
    // handler your owner business logic
    if([[values objectForKey:@"returnCode"] isEqualToString:@"0000"])
        return YES;
    else{
        if(failure){
            failure([NSError errorWithDomain:@"ddmodel.validate.error" code:1001 userInfo:nil],[values objectForKey:@"returnMessage"]);
        }
        return NO;
    }
}

@interface User : DDModel

@property (nonatomic, strong) NSNumber *id;
@property (nonatomic, copy) NSString *username;
@property (nonatomic, copy) NSString *avatarImageURLString;

@end

@interface Post : DDModel

@property (nonatomic, copy) NSString *text;
@property (nonatomic, strong) NSNumber *id;
@property (nonatomic, strong) User *user;


+ (void)getPostList:(id)params
           parentVC:(id)viewController
            showHUD:(BOOL)show
            success:(DDResponseSuccessBlock)success
            failure:(DDResponsesFailureBlock)failure;

@end

#import "Post.h"

@implementation Post

+ (NSString *)parseNode{
    return @"data";
}

// ovrride this method if your define propery is not the same key in json string. or the object contain Nested objects
+ (NSDictionary *)parseMappings{
    id userHandler = [User mappingWithKey:@"user" mapping:[User parseMappings]];
    NSDictionary *jsonMappings = @{@"user":userHandler};
    return jsonMappings;
}

// a demo method of get data
+ (void)getPostList:(id)params
           parentVC:(id)viewController
            showHUD:(BOOL)show
            success:(DDResponseSuccessBlock)success
            failure:(DDResponseFailureBlock)failure
{
    [[self class] get:@"stream/0/posts/stream/global" params:params showHUD:show parentViewController:viewController successBlock:success failureBlock:failure];
}

@end

@implementation User

+ (NSDictionary *)parseMappings{
    // support for KeyPath
    return @{@"avatar_image.url":@"avatarImageURLString"};
}

@end

/**
 *  Start a singleton HTTP client with url.
 *
 *  @param url HTTP target url
 */
+ (void)startWithURL:(NSString *)url;

/**
 *  Start a singleton HTTP client with url & delegate
 *
 *  @param url      HTTP target url
 *  @param delegate DDHttpClientDelegate
 */
+ (void)startWithURL:(NSString *)url delegate:(id<DDHttpClientDelegate>)delegate;

/**
 *  Set the HTTP header field value
 *
 *  @param keyValue keyValue
 */
+ (void)addHTTPHeaderFieldValue:(NSDictionary *)keyValue;

/**
 *  Remove the HTTP header field value
 *
 *  @param keyValue keyValue
 */
+ (void)removeHTTPHeaderFieldValue:(NSDictionary *)keyValue;

@protocol DDHttpClientDelegate <NSObject>

@optional
/**
 *  Parameter encode method if you should encode the parameter in your HTTP client
 *
 *  @param params original parameters
 *
 *  @return endcoded parameters
 */
- (NSDictionary *)encodeParameters:(NSDictionary *)params;

/**
 *  Response String decode methods in you HTTP client
 *
 *  @param responseString origin responseString
 *
 *  @return new responseString
 */
- (NSString *)decodeResponseString:(NSString *)responseString;

/**
 *  Check the response values is an avaliable value.
    e.g. You will sign in an account but you press a wrong username/password, server will response a error for you, you can catch them use this protocol methods and handle this error exception.
 *
 *  @param values  should check value
 *  @param failure failure block
 *
 *  @return true or false
 */
- (BOOL)checkResponseValueAvailable:(NSDictionary *)values failure:(DDResponseFailureBlock)failure;

@end

@protocol DDMappings <NSObject>

/**
 *  Set the parse node, every subclass override the method if you want parse any node
 *
 *  @return node
 */
+ (NSString *)parseNode;

/**
 *  Handle the mappings about the json key-value transform to a model object.
 The method support for KeyPathValue. e.g. you have a  @property name, you want get value from "{user:{name:'mike',id:10011},picture:'https://xxxx/headerimage/header01.jpg'}", you just set mapping dictionary is @{@"user.name":@"name"}.
 *
 *  @return mappings
 */
+ (NSDictionary *)parseMappings;

@end

/**
 *  Get json data first from db cache then from http server by HTTP GET Mehod.
 *
 *  @param path           HTTP Path
 *  @param params         GET Paramtters
 *  @param dbResult       db cache result block
 *  @param success        success block
 *  @param failure        failre block
 *
 *  @return NSURLSessionDataTask
 */
+ (NSURLSessionDataTask *)get:(NSString *)path
                       params:(id)params
                    dbSuccess:(DDSQLiteBlock)dbResult
                      success:(DDResponseSuccessBlock)success
                      failure:(DDResponsesFailureBlock)failure;

/**
 *  Get json data first from db cache then from http server by HTTP POST Mehod.
 *
 *  @param path           HTTP Path
 *  @param params         GET Paramtters
 *  @param dbResult       db cache result block
 *  @param success        success block
 *  @param failure        failre block
 *
 *  @return NSURLSessionDataTask
 */
+ (NSURLSessionDataTask *)post:(NSString *)path
                        params:(id)params
                     dbSuccess:(DDSQLiteBlock)dbResult
                       success:(DDResponseSuccessBlock)success
                       failure:(DDResponsesFailureBlock)failure;

/**
 *  Get json data from http server by HTTP GET Mehod.
 *
 *  @param path           HTTP Path
 *  @param params         GET Paramtters
 *  @param success        success block
 *  @param failure        failre block
 *
 *  @return NSURLSessionDataTask
 */
+ (NSURLSessionDataTask *)get:(NSString *)path
                       params:(id)params
                      success:(DDResponseSuccessBlock)success
                      failure:(DDResponsesFailureBlock)failure;

/**
 *  Get json data from http server by HTTP POST Mehod.
 *
 *  @param path           HTTP Path
 *  @param params         POST Paramtters
 *  @param success        success block
 *  @param failure        failre block
 *
 *  @return NSURLSessionDataTask
 */
+ (NSURLSessionDataTask *)post:(NSString *)path
                        params:(id)params
                       success:(DDResponseSuccessBlock)success
                       failure:(DDResponsesFailureBlock)failure;

/**
 *  Upload a data stream to http server by HTTP POST Method.
 *
 *  @param path           HTTP Path
 *  @param stream         stream data
 *  @param params         POST Parameters
 *  @param userInfo       userInfo dictionary
 *  @param success        success block
 *  @param failure        failure block
 *
 *  @return NSURLSessionDataTask
 */
+ (NSURLSessionDataTask *)post:(NSString *)path
                    fileStream:(NSData *)stream
                        params:(id)params
                      userInfo:(id)userInfo
                       success:(DDUploadReponseSuccessBlock)success
                       failure:(DDResponsesFailureBlock)failure;

/**
 *  Parse self entity into a dictionary
 *
 *  @return a dictionary of self entity
 */
- (NSDictionary *)propertiesOfObject;