如何更深入使用Moya
Moya 簡介
Moya
是一套基於Alamofire
的網路抽象層框架。
個人認為Alamofire
是基於URLSession
上,如何更方便的呼叫請求,而Moya
則是基於Alamofire
上,通過抽象 URLs 和 parameter等等,更好的管理API。
基本模板
Moya
在對於API的封裝是基於enum
,通過對於列舉不同端點的不同用法,生成請求。
enum GitHub {
case zen
case userProfile(String)
}
extension GitHub: TargetType {
var baseURL: URL { return URL (string: "https://api.github.com")! }
var path: String {
switch self {
case .zen:
return "/zen"
case .userProfile(let name):
return "/users/\(name)"
}
}
var method: Moya.Method {
return .get
}
var task: Task {
return .requestPlain
}
var sampleData: Data {
switch self {
case .zen:
return "Half measures are as bad as nothing at all.".data(using: String.Encoding.utf8)!
case .userProfile(let name):
return "{\"login\": \"\(name)\",\"id\": 100}".data(using: String .Encoding.utf8)!
}
}
var validationType: ValidationType {
return .successAndRedirectCodes
}
var headers: [String: String]? {
return nil
}
}
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通過列舉繼承TargetType
,新增細節實現。
var provider = MoyaProvider<GitHub>()
provider.request(target) { response in
if case .failure(let error) = response {
receivedError = error
}
}
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最後生成根據TargetType生成provider進行請求。
到此就是Moya
的基本實現。因為過於基本,不再贅述。
Codable
Codable
協議是蘋果提供解析資料的協議,在不使用第三方庫,如ObjectMapper
,SwiftyJson
的情況下,將伺服器返回的JSON
資料轉為model。
下面是一個簡單的Codable
示例:
struct Demo: Codable {
var name: String
var age: Int
}
func decode() {
let jsonString = "{\"name\":\"zhangsan\",\"age\":15}" // 模擬JSON資料
let decoder = JSONDecoder()
let data = jsonString.data(using: .utf8)!
let model = try! decoder.decode(Demo.self,from: data)
print(model) // Demo(name: "zhangsan",age: 15)
}
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在Moya
的Response
中已經封裝好了對應的處理
DemoProvider.provider.request(.zen) { (result) in
switch result {
case .success(let response):
if let model = try? response.map(Demo.self) {
success(model)
}
case .failure(let error):
break
}
}
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如果資料是在JSON的好幾個層級中,也可以通過設定keypath獲取:
{
data: {
name: "test",age: 15
}
}
try? response.map(Demo.self,atKeyPath: "data")
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要注意的是這裡函式還有一個引數叫做failsOnEmptyData
,預設設定為true
,如果返回的資料為空,會判定會解析失敗。
EndPoint
EndPoint是Moya的半個內部資料結構,由所用的TargetType生成,它最終被用來生成網路請求。 每個EndPoint 都儲存了下面的資料:
/// A string representation of the URL for the request.
public let url: String
/// A closure responsible for returning an `EndpointSampleResponse`. (單元測試)
public let sampleResponseClosure: SampleResponseClosure
/// The HTTP method for the request.
public let method: Moya.Method
/// The `Task` for the request.
public let task: Task
/// The HTTP header fields for the request.
public let httpHeaderFields: [String: String]?
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在Provider生成時,可以傳入endpointClosure,自定義TargetType到Endpoint的方式。
預設的實現方式:
final class func defaultEndpointMapping(for target: Target) -> Endpoint {
return Endpoint(
url: URL(target: target).absoluteString,sampleResponseClosure: { .networkResponse(200,target.sampleData) },method: target.method,task: target.task,httpHeaderFields: target.headers
)
}
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在這裡可以重新定義Endpoint的生成方式,比如:
// 將所有生成Endpoint改為get方式請求
let endpointClosure = { (target: MyTarget) -> Endpoint in
let url = URL(target: target).absoluteString
return Endpoint(url: url,sampleResponseClosure: {.networkResponse(200,target.sampleData)},method: .get,task: target.task)
}
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或者對已經生成的Endpoint修改:
let endpointClosure = { (target: MyTarget) -> Endpoint in
let defaultEndpoint = MoyaProvider.defaultEndpointMapping(for: target)
return defaultEndpoint.adding(newHTTPHeaderFields: ["APP_NAME": "MY_AWESOME_APP"])
}
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注意:如果直接對已經初始化的Endpoint修改,只能修改task以及新增header。
Request
在生成Endpoint之後,會從Endpoint再轉為URLRequst進行使用。
Moya的預設實現:
RequestResultClosure = (Result<URLRequest,MoyaError>) -> Void
final class func defaultRequestMapping(for endpoint: Endpoint,closure: RequestResultClosure) {
do {
let urlRequest = try endpoint.urlRequest()
closure(.success(urlRequest))
} catch MoyaError.requestMapping(let url) {
closure(.failure(MoyaError.requestMapping(url)))
} catch MoyaError.parameterEncoding(let error) {
closure(.failure(MoyaError.parameterEncoding(error)))
} catch {
closure(.failure(MoyaError.underlying(error,nil)))
}
}
public func urlRequest() throws -> URLRequest {
guard let requestURL = Foundation.URL(string: url) else {
throw MoyaError.requestMapping(url)
}
var request = URLRequest(url: requestURL)
request.httpMethod = method.rawValue
request.allHTTPHeaderFields = httpHeaderFields
switch task {
case .requestPlain,.uploadFile,.uploadMultipart,.downloadDestination:
return request
case .requestData(let data):
request.httpBody = data
return request
......
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因為內部已經實現如何生成Request,大多情況不需要修改urlRequest
,而是重新定義requestClosure,對已經生成好的request進行修改,下面是直接修改request的快取策略,以及錯誤處理:
let requestClosure = { (endpoint: Endpoint,done: MoyaProvider.RequestResultClosure) in
do {
var request = try endpoint.urlRequest()
request.cachePolicy = .reloadIgnoringCacheData
done(.success(request))
} catch {
done(.failure(MoyaError.underlying(error)))
}
}
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stubClosure
stubClosure實現:
/// Do not stub.
final class func neverStub(_: Target) -> Moya.StubBehavior {
return .never
}
/// Return a response immediately.
final class func immediatelyStub(_: Target) -> Moya.StubBehavior {
return .immediate
}
/// Return a response after a delay.
final class func delayedStub(_ seconds: TimeInterval) -> (Target) -> Moya.StubBehavior {
return { _ in return .delayed(seconds: seconds) }
}
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Moya的預設實現是neverStub,當使用immediatelyStub或者是delayedStub,請求網路時就不會走真實的資料,而是返回Target中SimpleData的資料,一般用於測試API返回資料的處理。
delayedStub相對於immediatelyStub指定了延遲時長,單位是秒。
callbackQueue
可以指定網路請求返回之後的callback執行緒。預設所有的請求將會被Alamofire放入background執行緒中,callbac將會在主執行緒中呼叫。
Manager
public typealias Manager = Alamofire.SessionManager
final class func defaultAlamofireManager() -> Manager {
let configuration = URLSessionConfiguration.default
configuration.httpAdditionalHeaders = Manager.defaultHTTPHeaders
let manager = Manager(configuration: configuration)
manager.startRequestsImmediately = false
return manager
}
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Moya中使用的Manager其實就是Alamofire的Manager。
可以設定Timeout,快取策略等等
let manager: SessionManager = {
let configuration = defaultURLSessionConfiguration
configuration.requestCachePolicy = .reloadIgnoringLocalCacheData
configuration.timeoutIntervalForRequest = 20
let trustPolicyManager = ServerTrustPolicyManager(policies:
[
"www.baidu.com": ServerTrustPolicy.disableEvaluation
]
)
let manager = SessionManager(configuration: configuration,serverTrustPolicyManager: trustPolicyManager)
return manager
}()
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Plugins
plugins
是遵守了PluginType
的外掛,一個provider可以方多個Plugin。
PluginType:
public protocol PluginType {
/// 在傳送request之前,還有機會對request修改
func prepare(_ request: URLRequest,target: TargetType) -> URLRequest
/// 傳送之前呼叫
func willSend(_ request: RequestType,target: TargetType)
/// 接受Response之後,在觸發callback之前
func didReceive(_ result: Result<Moya.Response,MoyaError>,target: TargetType)
/// 在呼叫Callback之前,還能修改result
func process(_ result: Result<Moya.Response,target: TargetType) -> Result<Moya.Response,MoyaError>
}
public extension PluginType {
func prepare(_ request: URLRequest,target: TargetType) -> URLRequest { return request }
func willSend(_ request: RequestType,target: TargetType) { }
func didReceive(_ result: Result<Moya.Response,target: TargetType) { }
func process(_ result: Result<Moya.Response,MoyaError> { return result }
}
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在Plugin中可以做很多事情
- 記錄網路請求
- 處理隱藏或者顯示網路activity progress
- 對request進行更多的處理
比如:
struct TestPlugin: PluginType {
// 對request進行更多的處理
func prepare(_ request: URLRequest,target: TargetType) -> URLRequest {
var request = request
if target is GitHub {
request.timeoutInterval = 5
}
return request
}
// 記錄網路請求
func willSend(_ request: RequestType,target: TargetType) {
print("start")
print(request.request?.url ?? "")
}
// 記錄網路請求
func didReceive(_ result: Result<Response,target: TargetType) {
print("end")
switch result {
case .success(let response):
print("end success")
print(response.request?.url ?? "")
case .failure(let error):
print("end failure")
print(error)
}
}
// 對返回的result進行修改
func process(_ result: Result<Response,target: TargetType) -> Result<Response,MoyaError> {
if case let .failure(error) = result {
return .failure(MoyaError.underlying(error,nil))
}
return result
}
}
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Moya也對Logger,activity等提供了預設實現的Plugin,更多細節就不詳細說明了。
trackInflights
原始碼看了半天還是看不明白,希望懂的朋友能告訴我是怎麼用的。
MultiTarget
一般場景下,是一個targetType對應一個Provider
let githubProvider = MoyaProvider<GitHub>(stubClosure: MoyaProvider.immediatelyStub,trackInflights: true)
let demoProvider = MoyaProvider<Demo>(stubClosure: MoyaProvider.immediatelyStub,trackInflights: true)
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但是如果像讓這個Provider更通用,可以寫為:
let commonProvider = MoyaProvider<MultiTarget>()
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呼叫的時候指定TargetType即可:
commonProvider.request(MultiTarget(GitHub.zen)) { result in
...
}
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流程
補一張網上找到的流程圖