Alamofire 基础使用

一、发起请求

1. 参数
2. ParameterEncoder 参数编码器
* 2.1 JSON参数编码器
* 2.2 Form参数编码器
3. HTTP Headers 请求头设置
4. 响应处理

二、下载文件

下载Data
下载到指定目录
下载进度
恢复下载

三、上传文件

上传 Data
上传文件
上传 Multipart Data
上传进度

Alamofire是基于Apple提供的 URL加载系统，核心是URLSession和URLSessionTask子类。早期版本使用Alamofire.request()，5.0版本使用AF命名，AF引用Session.default

一、发起请求

简单示例：

AF.request("https://httpbin.org/get").response { response in
    debugPrint(response)
}

两个发起请求的API

/// 1. 配置请求组成 URLRequest、本篇主要内容（基础用法）
open func request(_ convertible: URLConvertible,
                                         method: HTTPMethod = .get,
                                         parameters: Parameters? = nil,
                                         encoder: ParameterEncoder = URLEncodedFormParameterEncoder.default,
                                         headers: HTTPHeaders? = nil,
                                         interceptor: RequestInterceptor? = nil) -> DataRequest

/// 2. 直接请求组装好的 URLRequest （高级用法）
open func request(_ urlRequest: URLRequestConvertible, 
                  interceptor: RequestInterceptor? = nil) -> DataRequest

1. 参数

只要参数遵循Encodable协议，那么最终ParameterEncoder都会把Parameter encode成需要的数据类型

举个例子

struct Login: Encodable {
    let email:String
    let password:String
}

let login = Login(email: "aaa", password: "bbb")
AF.request("https://httpbin.org/post",
               method: .post,
               parameters: login,
               encoder: JSONParameterEncoder.default)
    .response { response in
        debugPrint(response)
}

2. ParameterEncoder 参数编码器

参数编码器最终决定了参数在请求中的存在的样式

我们通过参数编码器把参数编码成服务器需要的数据类型

Alamofire提供了2个两种编码器

JSONParameterEncoder
URLEncodedFormParameterEncoder

2.1 JSON参数编码器

JSONParameterEncoder 对应的 Content-Type 为 application/json

default
prettyPrinted 好看的格式打印
sortedKeys key排序

/// 最终都是调用 encode 将参数转为 Data 保存在 httpBody 中
open func encode(_ value: T) throws -> Data where T : Encodable

let data = try encoder.encode(parameters)
request.httpBody = data

2.2 Form参数编码器

URLEncodedFormParameterEncoder 对应的 Content-Type 为

application/x-www-form-urlencoded; charset=utf-8

Form参数编码器只有一个默认的编码器default

Destination 决定参数存放的位置
- methodDependent [.get, .head, .delete] 拼接URL ，默认使用此方式
- queryString 拼接URL
- httpBody

/// httpBody 调用encode 将参数转为 Data 保存在 httpBody 中
public func encode(_ value: Encodable) throws -> Data
/// 拼接URL获得新的URL
public func encode(_ value: Encodable) throws -> String {
    ...
    URLEncodedFormEncoder.encode(value)
    ...
}

URLEncodedFormEncoder 决定了参数中不同类型的key,value编码方式
- ArrayEncoding
  - brackets key[] 默认
  - noBrackets key
- BoolEncoding
  - numeric true as 1, false as 0. 默认
  - literal true as "true", false as "false"
- DataEncoding
  - deferredToData nil
  - base64 data.base64EncodedString() 默认
  - custom((Data) throws -> String)
- DateEncoding
  - deferredToDate nil默认
  - secondsSince1970 String(date.timeIntervalSince1970)
  - millisecondsSince1970 String(date.timeIntervalSince1970 * 1000.0)
  - iso8601 ISO8601DateFormatter()
  - formatted(DateFormatter) formatter.string(from: date)
  - custom((Date) throws -> String).
- KeyEncoding
  - useDefaultKeys 原样式默认
  - convertToSnakeCase oneTwoThree becomes one_two_three
  - convertToKebabCase oneTwoThree becomes one-two-three.
  - capitalized oneTwoThree becomes OneTwoThree
  - uppercased oneTwoThree becomes ONETWOTHREE.
  - lowercased oneTwoThree becomes onetwothree
  - custom((String) -> String)
- SpaceEncoding
  - percentEscaped string.replacingOccurrences(of: " ", with: "%20")
  - plusReplaced string.replacingOccurrences(of: " ", with: "+")
- alphabetizeKeyValuePairs key/value 按照字母排序，默认true

3. HTTP Headers 请求头设置

提供3种初始化方式

/// 1. 无参构造
public init() {}

/// 通过以下方式添加值
func add(name: String, value: String)
func add(_ header: HTTPHeader)

/// 2. 通过 HTTPHeader 数组构造
public init(_ headers: [HTTPHeader])

let headers: HTTPHeaders = [
    HTTPHeader(name: "Authorization", value: "Basic VXNlcm5hbWU6UGFzc3dvcmQ="),
    HTTPHeader(name: "Accept", value: "application/json")
]

AF.request("https://httpbin.org/headers", headers: headers).responseJSON { response in
    debugPrint(response)
}

/// 3. 通过key/value 构造
public init(_ dictionary: [String: String])

let headers: HTTPHeaders = [
    "Authorization": "Basic VXNlcm5hbWU6UGFzc3dvcmQ=",
    "Accept": "application/json"
]

AF.request("https://httpbin.org/headers", headers: headers).responseJSON { response in
    debugPrint(response)
}

4. 响应处理

Alamofire 提供了4种 Response序列化工具

DataResponseSerializer 解析为Data

// Response Handler - Unserialized Response
func response(queue: DispatchQueue = .main, 
              completionHandler: @escaping (AFDataResponse) -> Void) -> Self

// Response Data Handler - Serialized into Data
func responseData(queue: DispatchQueue = .main,
                  dataPreprocessor: DataPreprocessor = DataResponseSerializer.defaultDataPreprocessor,
                  emptyResponseCodes: Set = DataResponseSerializer.defaultEmptyResponseCodes,
                  emptyRequestMethods: Set = DataResponseSerializer.defaultEmptyRequestMethods,
                  completionHandler: @escaping (AFDataResponse) -> Void) -> Self

//示例
AF.request("https://httpbin.org/get").responseData { response in
    debugPrint("Response: \(response)")
}

StringResponseSerializer 解析为String

// Response String Handler - Serialized into String
func responseString(queue: DispatchQueue = .main,
                    dataPreprocessor: DataPreprocessor = StringResponseSerializer.defaultDataPreprocessor,
                    encoding: String.Encoding? = nil,
                    emptyResponseCodes: Set = StringResponseSerializer.defaultEmptyResponseCodes,
                    emptyRequestMethods: Set = StringResponseSerializer.defaultEmptyRequestMethods,
                    completionHandler: @escaping (AFDataResponse) -> Void) -> Self



//示例
AF.request("https://httpbin.org/get").responseString { response in
    debugPrint("Response: \(response)")
}

JSONResponseSerializer 解析为JSON

// Response JSON Handler - Serialized into Any Using JSONSerialization
func responseJSON(queue: DispatchQueue = .main,
                  dataPreprocessor: DataPreprocessor = JSONResponseSerializer.defaultDataPreprocessor,
                  emptyResponseCodes: Set = JSONResponseSerializer.defaultEmptyResponseCodes,
                  emptyRequestMethods: Set = JSONResponseSerializer.defaultEmptyRequestMethods,
                  options: JSONSerialization.ReadingOptions = .allowFragments,
                  completionHandler: @escaping (AFDataResponse) -> Void) -> Self
//示例
AF.request("https://httpbin.org/get").responseJSON { response in
    debugPrint("Response: \(response)")
}

DecodableResponseSerializer 解析为指定类型<T: Decodable>

// Response Decodable Handler - Serialized into Decodable Type
func responseDecodable(of type: T.Type = T.self,
                                     queue: DispatchQueue = .main,
                                     dataPreprocessor: DataPreprocessor = DecodableResponseSerializer.defaultDataPreprocessor,
                                     decoder: DataDecoder = JSONDecoder(),
                                     emptyResponseCodes: Set = DecodableResponseSerializer.defaultEmptyResponseCodes,
                                     emptyRequestMethods: Set = DecodableResponseSerializer.defaultEmptyRequestMethods,
                                     completionHandler: @escaping (AFDataResponse) -> Void) -> Self

//示例
struct HTTPBinResponse: Decodable { let url: String }
AF.request("https://httpbin.org/get").responseDecodable(of: HTTPBinResponse.self) { response in
    debugPrint("Response: \(response)")
}

DataResponseSerializerProtocol 使用自定义解析 Serializer: DataResponseSerializerProtocol

// Response Serializer Handler - Serialize using the passed Serializer
func response(queue: DispatchQueue = .main,
                                                          responseSerializer: Serializer,
                                                          completionHandler: @escaping (AFDataResponse) -> Void) -> Self

//示例 自定义解析为 Dictionary
public final class DictionaryResponseSerializer: ResponseSerializer {
    public func serialize(request: URLRequest?,
                          response: HTTPURLResponse?,
                          data: Data?, error: Error?) throws -> Dictionary {
        guard error == nil else { throw error! }

        guard let data = data, !data.isEmpty else {
            guard emptyResponseAllowed(forRequest: request, response: response) else {
                throw AFError.responseSerializationFailed(reason: .inputDataNilOrZeroLength)
            }
            return [:]
        }
        do {
            return try JSONSerialization.jsonObject(with: data, options: JSONSerialization.ReadingOptions.fragmentsAllowed) as! Dictionary
        } catch {
            throw AFError.responseSerializationFailed(reason: .jsonSerializationFailed(error: error))
        }
    }
}

AF.request("https://httpbin.org/get").response(responseSerializer: DictionaryResponseSerializer()) { (response) in
    switch response.result {
    case .success(let bin):
        debugPrint(bin)
    case .failure(let error):
        debugPrint(error)
    }
}

二、下载文件

下载Data

AF.download("https://httpbin.org/image/png").responseData { response in
    if let data = response.value {
        let image = UIImage(data: data)
    }
}

下载到指定目录

let destination = DownloadRequest.suggestedDownloadDestination(for: .documentDirectory)
AF.download("https://httpbin.org/image/png", to: destination).response { response in
    debugPrint(response)

    if response.error == nil, let imagePath = response.fileURL?.path {
        let image = UIImage(contentsOfFile: imagePath)
    }
}

下载进度

AF.download("https://httpbin.org/image/png")
    .downloadProgress { progress in
        print("Download Progress: \(progress.fractionCompleted)")
    }
    .responseData { response in
        if let data = response.value {
            let image = UIImage(data: data)
        }
    }

恢复下载

var resumeData: Data!

let download = AF.download("https://httpbin.org/image/png").responseData { response in
    if let data = response.value {
        let image = UIImage(data: data)
    }
}

// download.cancel(producingResumeData: true) // Makes resumeData available in response only.
download.cancel { data in
    resumeData = data
}

AF.download(resumingWith: resumeData).responseData { response in
    if let data = response.value {
        let image = UIImage(data: data)
    }
}

三、上传文件

上传 Data

let data = Data("data".utf8)

AF.upload(data, to: "https://httpbin.org/post").responseDecodable(of: HTTPBinResponse.self) { response in
    debugPrint(response)
}

上传文件

let fileURL = Bundle.main.url(forResource: "video", withExtension: "mov")

AF.upload(fileURL, to: "https://httpbin.org/post").responseDecodable(of: HTTPBinResponse.self) { response in
    debugPrint(response)
}

上传 Multipart Data

AF.upload(multipartFormData: { multipartFormData in
    multipartFormData.append(Data("one".utf8), withName: "one")
    multipartFormData.append(Data("two".utf8), withName: "two")
}, to: "https://httpbin.org/post")
    .responseDecodable(of: HTTPBinResponse.self) { response in
        debugPrint(response)
    }

上传进度

let fileURL = Bundle.main.url(forResource: "video", withExtension: "mov")

AF.upload(fileURL, to: "https://httpbin.org/post")
    .uploadProgress { progress in
        print("Upload Progress: \(progress.fractionCompleted)")
    }
    .responseDecodable(of: HTTPBinResponse.self) { response in
        debugPrint(response)
    }

最后封装了一个基于Moya&RXSwift&HandyJSON的网络库使用：PomeloNet

Alamofire 基础使用

一、发起请求

二、下载文件

三、上传文件

一、发起请求

1. 参数

2. ParameterEncoder 参数编码器

2.1 JSON参数编码器

2.2 Form参数编码器

3. HTTP Headers 请求头设置

4. 响应处理

二、下载文件

下载Data

下载到指定目录

下载进度

恢复下载

三、上传文件

上传 Data

上传文件

上传 Multipart Data

上传进度

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