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
其他回答
这个问题已经有很多优秀而广泛的答案,但我觉得我必须提一下,因为没有人提过。
斯威夫特的Alamofire。https://github.com/Alamofire/Alamofire
它是由与AFNetworking相同的人创建的,但在设计时更直接地考虑了Swift。
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。
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。
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
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.
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