I'm an iOS developer with some experience and this question is really interesting to me. I saw a lot of different resources and materials on this topic, but nevertheless I'm still confused. What is the best architecture for an iOS networked application? I mean basic abstract framework, patterns, which will fit every networking application whether it is a small app which only have a few server requests or a complex REST client. Apple recommends to use MVC as a basic architectural approach for all iOS applications, but neither MVC nor the more modern MVVM patterns explain where to put network logic code and how to organize it in general. Do I need to develop something like MVCS(S for Service) and in this Service layer put all API requests and other networking logic, which in perspective may be really complex? After doing some research I found two basic approaches for this. Here it was recommended to create a separate class for every network request to web-service API (like LoginRequest class or PostCommentRequest class and so on) which all inherits from the base request abstract class AbstractBaseRequest and in addition to create some global network manager which encapsulates common networking code and other preferences (it may be AFNetworking customisation or RestKit tuning, if the we have complex object mappings and persistence, or even an own network communication implementation with standard API). But this approach seems an overhead for me. Another approach is to have some singleton API dispatcher or manager class as in the first approach, but not to create classes for every request and instead to encapsulate every request as an instance public method of this manager class like: fetchContacts, loginUser methods, etc. So, what is the best and correct way? Are there other interesting approaches I don't know yet? And should I create another layer for all this networking stuff like Service, or NetworkProvider layer or whatever on top of my MVC architecture, or this layer should be integrated (injected) into existing MVC layers e.g. Model? I know there exists beautiful approaches, or how then such mobile monsters like Facebook client or LinkedIn client deal with exponentially growing complexity of networking logic? I know there are no exact and formal answer to the problem. The goal of this question is to collect the most interesting approaches from experienced iOS developers. The best suggested approach will be marked as accepted and awarded with a reputation bounty, others will be upvoted. It is mostly a theoretical and research question. I want to understand basic, abstract and correct architectural approach for networking applications in iOS. I hope for detailed explanation from experienced developers.


当前回答

我使用从这里得到的方法:https://github.com/Constantine-Fry/Foursquare-API-v2。我已经在Swift中重写了这个库,你可以从这部分代码中看到架构方法:

typealias OpertaionCallback = (success: Bool, result: AnyObject?) -> ()

class Foursquare{
    var authorizationCallback: OperationCallback?
    var operationQueue: NSOperationQueue
    var callbackQueue: dispatch_queue_t?

    init(){
        operationQueue = NSOperationQueue()
        operationQueue.maxConcurrentOperationCount = 7;
        callbackQueue = dispatch_get_main_queue();
    }

    func checkIn(venueID: String, shout: String, callback: OperationCallback) -> NSOperation {
        let parameters: Dictionary <String, String> = [
            "venueId":venueID,
            "shout":shout,
            "broadcast":"public"]
        return self.sendRequest("checkins/add", parameters: parameters, httpMethod: "POST", callback: callback)
    }

    func sendRequest(path: String, parameters: Dictionary <String, String>, httpMethod: String, callback:OperationCallback) -> NSOperation{
        let url = self.constructURL(path, parameters: parameters)
        var request = NSMutableURLRequest(URL: url)
        request.HTTPMethod = httpMethod
        let operation = Operation(request: request, callbackBlock: callback, callbackQueue: self.callbackQueue!)
        self.operationQueue.addOperation(operation)
        return operation
    }

    func constructURL(path: String, parameters: Dictionary <String, String>) -> NSURL {
        var parametersString = kFSBaseURL+path
        var firstItem = true
        for key in parameters.keys {
            let string = parameters[key]
            let mark = (firstItem ? "?" : "&")
            parametersString += "\(mark)\(key)=\(string)"
            firstItem = false
        }
    return NSURL(string: parametersString.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding))
    }
}

class Operation: NSOperation {
    var callbackBlock: OpertaionCallback
    var request: NSURLRequest
    var callbackQueue: dispatch_queue_t

    init(request: NSURLRequest, callbackBlock: OpertaionCallback, callbackQueue: dispatch_queue_t) {
        self.request = request
        self.callbackBlock = callbackBlock
        self.callbackQueue = callbackQueue
    }

    override func main() {
        var error: NSError?
        var result: AnyObject?
        var response: NSURLResponse?

        var recievedData: NSData? = NSURLConnection.sendSynchronousRequest(self.request, returningResponse: &response, error: &error)

        if self.cancelled {return}

        if recievedData{
            result = NSJSONSerialization.JSONObjectWithData(recievedData, options: nil, error: &error)
            if result != nil {
                if result!.isKindOfClass(NSClassFromString("NSError")){
                    error = result as? NSError
            }
        }

        if self.cancelled {return}

        dispatch_async(self.callbackQueue, {
            if (error) {
                self.callbackBlock(success: false, result: error!);
            } else {
                self.callbackBlock(success: true, result: result!);
            }
            })
    }

    override var concurrent:Bool {get {return true}}
}

基本上,有一个NSOperation子类,它生成NSURLRequest,解析JSON响应,并将回调块和结果添加到队列中。主API类构造NSURLRequest,初始化NSOperation子类并将其添加到队列中。

其他回答

试试https://github.com/kevin0571/STNetTaskQueue

在分开的类中创建API请求。

STNetTaskQueue将处理线程和委托/回调。

可针对不同协议进行扩展。

因为所有iOS应用程序都是不同的,所以我认为这里有不同的方法可以考虑,但我通常是这样做的: 创建一个中央管理器(单例)类来处理所有API请求(通常命名为apiccommunicator),每个实例方法都是一个API调用。有一个中心(非公共)方法:

-(RACSignal *)sendGetToServerToSubPath:(NSString *)path withParameters:(NSDictionary *)params;

For the record, I use 2 major libraries/frameworks, ReactiveCocoa and AFNetworking. ReactiveCocoa handles async networking responses perfectly, you can do (sendNext:, sendError:, etc.). This method calls the API, gets the results and sends them through RAC in 'raw' format (like NSArray what AFNetworking returns). Then a method like getStuffList: which called the above method subscribes to it's signal, parses the raw data into objects (with something like Motis) and sends the objects one by one to the caller (getStuffList: and similar methods also return a signal that the controller can subscribe to). The subscribed controller receives the objects by subscribeNext:'s block and handles them. I tried many ways in different apps but this one worked the best out of all so I've been using this in a few apps recently, it fits both small and big projects and it's easy to extend and maintain if something needs to be modified. Hope this helps, I'd like to hear others' opinions about my approach and maybe how others think this could be maybe improved.

在我的情况下,我通常使用ResKit库来设置网络层。它提供了易于使用的解析。它减少了我为不同的响应设置映射的工作量。

我只添加了一些代码来自动设置映射。 我为我的模型定义了基类(不是协议,因为有很多代码来检查一些方法是否被实现,模型本身的代码更少):

MappableEntry。h

@interface MappableEntity : NSObject

+ (NSArray*)pathPatterns;
+ (NSArray*)keyPathes;
+ (NSArray*)fieldsArrayForMapping;
+ (NSDictionary*)fieldsDictionaryForMapping;
+ (NSArray*)relationships;

@end

MappableEntry米。

@implementation MappableEntity

+(NSArray*)pathPatterns {
    return @[];
}

+(NSArray*)keyPathes {
    return nil;
}

+(NSArray*)fieldsArrayForMapping {
    return @[];
}

+(NSDictionary*)fieldsDictionaryForMapping {
    return @{};
}

+(NSArray*)relationships {
    return @[];
}

@end

关系是表示响应中嵌套对象的对象:

RelationshipObject.h

@interface RelationshipObject : NSObject

@property (nonatomic,copy) NSString* source;
@property (nonatomic,copy) NSString* destination;
@property (nonatomic) Class mappingClass;

+(RelationshipObject*)relationshipWithKey:(NSString*)key andMappingClass:(Class)mappingClass;
+(RelationshipObject*)relationshipWithSource:(NSString*)source destination:(NSString*)destination andMappingClass:(Class)mappingClass;

@end

RelationshipObject.m

@implementation RelationshipObject

+(RelationshipObject*)relationshipWithKey:(NSString*)key andMappingClass:(Class)mappingClass {
    RelationshipObject* object = [[RelationshipObject alloc] init];
    object.source = key;
    object.destination = key;
    object.mappingClass = mappingClass;
    return object;
}

+(RelationshipObject*)relationshipWithSource:(NSString*)source destination:(NSString*)destination andMappingClass:(Class)mappingClass {
    RelationshipObject* object = [[RelationshipObject alloc] init];
    object.source = source;
    object.destination = destination;
    object.mappingClass = mappingClass;
    return object;
}

@end

然后我像这样为RestKit设置映射:

ObjectMappingInitializer.h

@interface ObjectMappingInitializer : NSObject

+(void)initializeRKObjectManagerMapping:(RKObjectManager*)objectManager;

@end

ObjectMappingInitializer.m

@interface ObjectMappingInitializer (Private)

+ (NSArray*)mappableClasses;

@end

@implementation ObjectMappingInitializer

+(void)initializeRKObjectManagerMapping:(RKObjectManager*)objectManager {

    NSMutableDictionary *mappingObjects = [NSMutableDictionary dictionary];

    // Creating mappings for classes
    for (Class mappableClass in [self mappableClasses]) {
        RKObjectMapping *newMapping = [RKObjectMapping mappingForClass:mappableClass];
        [newMapping addAttributeMappingsFromArray:[mappableClass fieldsArrayForMapping]];
        [newMapping addAttributeMappingsFromDictionary:[mappableClass fieldsDictionaryForMapping]];
        [mappingObjects setObject:newMapping forKey:[mappableClass description]];
    }

    // Creating relations for mappings
    for (Class mappableClass in [self mappableClasses]) {
        RKObjectMapping *mapping = [mappingObjects objectForKey:[mappableClass description]];
        for (RelationshipObject *relation in [mappableClass relationships]) {
            [mapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:relation.source toKeyPath:relation.destination withMapping:[mappingObjects objectForKey:[relation.mappingClass description]]]];
        }
    }

    // Creating response descriptors with mappings
    for (Class mappableClass in [self mappableClasses]) {
        for (NSString* pathPattern in [mappableClass pathPatterns]) {
            if ([mappableClass keyPathes]) {
                for (NSString* keyPath in [mappableClass keyPathes]) {
                    [objectManager addResponseDescriptor:[RKResponseDescriptor responseDescriptorWithMapping:[mappingObjects objectForKey:[mappableClass description]] method:RKRequestMethodAny pathPattern:pathPattern keyPath:keyPath statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)]];
                }
            } else {
                [objectManager addResponseDescriptor:[RKResponseDescriptor responseDescriptorWithMapping:[mappingObjects objectForKey:[mappableClass description]] method:RKRequestMethodAny pathPattern:pathPattern keyPath:nil statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)]];
            }
        }
    }

    // Error Mapping
    RKObjectMapping *errorMapping = [RKObjectMapping mappingForClass:[Error class]];
    [errorMapping addAttributeMappingsFromArray:[Error fieldsArrayForMapping]];
    for (NSString *pathPattern in Error.pathPatterns) {
        [[RKObjectManager sharedManager] addResponseDescriptor:[RKResponseDescriptor responseDescriptorWithMapping:errorMapping method:RKRequestMethodAny pathPattern:pathPattern keyPath:nil statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassClientError)]];
    }
}

@end

@implementation ObjectMappingInitializer (Private)

+ (NSArray*)mappableClasses {
    return @[
        [FruiosPaginationResults class],
        [FruioItem class],
        [Pagination class],
        [ContactInfo class],
        [Credentials class],
        [User class]
    ];
}

@end

MappableEntry实现的一些例子:

User.h

@interface User : MappableEntity

@property (nonatomic) long userId;
@property (nonatomic, copy) NSString *username;
@property (nonatomic, copy) NSString *email;
@property (nonatomic, copy) NSString *password;
@property (nonatomic, copy) NSString *token;

- (instancetype)initWithUsername:(NSString*)username email:(NSString*)email password:(NSString*)password;

- (NSDictionary*)registrationData;

@end

User.m

@implementation User

- (instancetype)initWithUsername:(NSString*)username email:(NSString*)email password:(NSString*)password {
    if (self = [super init]) {
        self.username = username;
        self.email = email;
        self.password = password;
    }
    return self;
}

- (NSDictionary*)registrationData {
    return @{
        @"username": self.username,
        @"email": self.email,
        @"password": self.password
    };
}

+ (NSArray*)pathPatterns {
    return @[
        [NSString stringWithFormat:@"/api/%@/users/register", APIVersionString],
        [NSString stringWithFormat:@"/api/%@/users/login", APIVersionString]
    ];
}

+ (NSArray*)fieldsArrayForMapping {
    return @[ @"username", @"email", @"password", @"token" ];
}

+ (NSDictionary*)fieldsDictionaryForMapping {
    return @{ @"id": @"userId" };
}

@end

现在关于请求包装:

我有头文件与块定义,以减少行长度在所有APIRequest类:

APICallbacks.h

typedef void(^SuccessCallback)();
typedef void(^SuccessCallbackWithObjects)(NSArray *objects);
typedef void(^ErrorCallback)(NSError *error);
typedef void(^ProgressBlock)(float progress);

我的APIRequest类的例子,我正在使用:

LoginAPI。h

@interface LoginAPI : NSObject

- (void)loginWithCredentials:(Credentials*)credentials onSuccess:(SuccessCallbackWithObjects)onSuccess onError:(ErrorCallback)onError;

@end

公元LoginAPI。

@implementation LoginAPI

- (void)loginWithCredentials:(Credentials*)credentials onSuccess:(SuccessCallbackWithObjects)onSuccess onError:(ErrorCallback)onError {
    [[RKObjectManager sharedManager] postObject:nil path:[NSString stringWithFormat:@"/api/%@/users/login", APIVersionString] parameters:[credentials credentialsData] success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) {
        onSuccess(mappingResult.array);
    } failure:^(RKObjectRequestOperation *operation, NSError *error) {
        onError(error);
    }];
}

@end

在代码中,你只需要初始化API对象,并在需要时调用它:

SomeViewController。m

@implementation SomeViewController {
    LoginAPI *_loginAPI;
    // ...
}

- (void)viewDidLoad {
    [super viewDidLoad];

    _loginAPI = [[LoginAPI alloc] init];
    // ...
}

// ...

- (IBAction)signIn:(id)sender {
    [_loginAPI loginWithCredentials:_credentials onSuccess:^(NSArray *objects) {
        // Success Block
    } onError:^(NSError *error) {
        // Error Block
    }];
}

// ...

@end

我的代码并不完美,但很容易设置一次,并用于不同的项目。如果任何人都感兴趣,我可以花一些时间,在GitHub和CocoaPods上为它做一个通用的解决方案。

我认为目前中型项目使用MVVM架构,大型项目使用VIPER架构 并努力实现

面向协议编程 软件设计模式 S.O.L.D原则 泛型编程 不要重复自己(DRY)

以及构建iOS网络应用程序的架构方法(REST客户端)

对于代码干净易读的分离问题,避免重复:

import Foundation
enum DataResponseError: Error {
    case network
    case decoding

    var reason: String {
        switch self {
        case .network:
            return "An error occurred while fetching data"
        case .decoding:
            return "An error occurred while decoding data"
        }
    }
}

extension HTTPURLResponse {
    var hasSuccessStatusCode: Bool {
        return 200...299 ~= statusCode
    }
}

enum Result<T, U: Error> {
    case success(T)
    case failure(U)
}

依存关系反演

 protocol NHDataProvider {
        func fetchRemote<Model: Codable>(_ val: Model.Type, url: URL, completion: @escaping (Result<Codable, DataResponseError>) -> Void)
    }

主要负责:

  final class NHClientHTTPNetworking : NHDataProvider {

        let session: URLSession

        init(session: URLSession = URLSession.shared) {
            self.session = session
        }

        func fetchRemote<Model: Codable>(_ val: Model.Type, url: URL,
                             completion: @escaping (Result<Codable, DataResponseError>) -> Void) {
            let urlRequest = URLRequest(url: url)
            session.dataTask(with: urlRequest, completionHandler: { data, response, error in
                guard
                    let httpResponse = response as? HTTPURLResponse,
                    httpResponse.hasSuccessStatusCode,
                    let data = data
                    else {
                        completion(Result.failure(DataResponseError.network))
                        return
                }
                guard let decodedResponse = try? JSONDecoder().decode(Model.self, from: data) else {
                    completion(Result.failure(DataResponseError.decoding))
                    return
                }
                completion(Result.success(decodedResponse))
            }).resume()
        }
    }

你会发现这里是GitHub MVVM架构与rest API Swift项目

在移动软件工程中,应用最广泛的是Clean Architecture + MVVM和Redux模式。

Clean Architecture + MVVM由3层组成: 域、表示、数据层。 表示层和数据存储库层依赖于域层:

Presentation Layer -> Domain Layer <- Data Repositories Layer

表示层由视图模型和视图(MVVM)组成:

Presentation Layer (MVVM) = ViewModels + Views
Domain Layer = Entities + Use Cases + Repositories Interfaces
Data Repositories Layer = Repositories Implementations + API (Network) + Persistence DB

在本文中,将对Clean Architecture + MVVM进行更详细的描述 https://tech.olx.com/clean-architecture-and-mvvm-on-ios-c9d167d9f5b3