Alamofire从基础到进阶 基础请求与响应（一）
2018-03-30 本文已影响276人
Hellolad
Alamofire
Version：4.5.1
Swift Version: 4.0.3
Podfiles
# Uncomment the next line to define a global platform for your proje
platform :ios, '8.0'
target 'UseageAlamofire' do
use_frameworks!
pod 'Alamofire'
end
目录：
Alamofire从基础到进阶 基础请求与响应（一）
Alamofire从基础到进阶 小技巧（二）
创建一个简单的Request
let request = Alamofire.request("http://httpbin.org/ip")
print("request = \(request)")
输出：request = GET http://httpbin.org/ip
上面的 GET 是请求类型，后面紧跟的就是你的请求的地址，还有另外两种创建一个Request的方式：
request(_ urlRequest: ）-
request(_ url:, method:, parameters:, encoding:, headers: )
我们使用一下看看效果：
let urlRequest = URLRequest(url: URL(string: "http://httpbin.org/ip")!)
let request2 = Alamofire.request(urlRequest)
print("request2 = \(request2)")
输出：request2 = GET http://httpbin.org/ip
let url = "http://httpbin.org/ip"
let method: HTTPMethod = .get
let parameters: Parameters = ["name": "chao"]
let encoding: URLEncoding = .default
let headers: HTTPHeaders = ["Content-Type": "application/json"]
let request3 = Alamofire.request(url, method: method, parameters: parameters, encoding: encoding, headers: headers)
print("request3 = \(request3)")
输出：request3 = GET http://httpbin.org/ip?name=chao
使用一下Response响应
我们已经学会了用Alamofire创建一个Request，我们最终想要的是从服务器拿到数据，我们可以这样写：
let url2 = "http://httpbin.org/ip"
Alamofire.request(url2).response(completionHandler: { defaultResponse in
print("request = ", defaultResponse.request)
print("-----------------------------------")
print("response = ", defaultResponse.response)
print("-----------------------------------")
print("data = ", defaultResponse.data)
print("-----------------------------------")
print("error = ", defaultResponse.error)
print("-----------------------------------")
print("metrics = ", defaultResponse.metrics)
print("-----------------------------------")
print("timeline = ", defaultResponse.timeline)
})
输出：
response = Optional(<NSHTTPURLResponse: 0x60000002ff00> { URL: http://httpbin.org/ip } { Status Code: 200, Headers {
"Access-Control-Allow-Credentials" = (
true
);
"Access-Control-Allow-Origin" = (
"*"
);
Connection = (
"keep-alive"
);
"Content-Length" = (
32
);
"Content-Type" = (
"application/json"
);
Date = (
"Fri, 30 Mar 2018 10:41:03 GMT"
);
Server = (
"meinheld/0.6.1"
);
Via = (
"1.1 vegur"
);
"X-Powered-By" = (
Flask
);
"X-Processed-Time" = (
0
);
} })
-----------------------------------
data = Optional(32 bytes)
-----------------------------------
error = nil
-----------------------------------
metrics = Optional((Task Interval) <_NSConcreteDateInterval: 0x600000030e40> (Start Date) 2018-03-30 10:41:03 +0000 + (Duration) 0.677700 seconds = (End Date) 2018-03-30 10:41:03 +0000
(Redirect Count) 0
(Transaction Metrics) (Request) <NSURLRequest: 0x600000012b60> { URL: http://httpbin.org/ip }
(Response) <NSHTTPURLResponse: 0x60000002f580> { URL: http://httpbin.org/ip } { Status Code: 200, Headers {
"Access-Control-Allow-Credentials" = (
true
);
"Access-Control-Allow-Origin" = (
"*"
);
Connection = (
"keep-alive"
);
"Content-Length" = (
32
);
"Content-Type" = (
"application/json"
);
Date = (
"Fri, 30 Mar 2018 10:32:49 GMT"
);
Server = (
"meinheld/0.6.1"
);
Via = (
"1.1 vegur"
);
"X-Powered-By" = (
Flask
);
"X-Processed-Time" = (
0
);
} }
(Fetch Start) 2018-03-30 10:41:03 +0000
(Domain Lookup Start) (null)
(Domain Lookup End) (null)
(Connect Start) (null)
(Secure Connection Start) (null)
(Secure Connection End) (null)
(Connect End) (null)
(Request Start) 2018-03-30 10:41:03 +0000
(Request End) 2018-03-30 10:41:03 +0000
(Response Start) 2018-03-30 10:41:03 +0000
(Response End) 2018-03-30 10:41:03 +0000
(Protocol Name) (null)
(Proxy Connection) NO
(Reused Connection) YES
(Fetch Type) Local Cache
(Request) <NSURLRequest: 0x600000012a10> { URL: http://httpbin.org/ip }
(Response) <NSHTTPURLResponse: 0x60000002fb60> { URL: http://httpbin.org/ip } { Status Code: 200, Headers {
"Access-Control-Allow-Credentials" = (
true
);
"Access-Control-Allow-Origin" = (
"*"
);
Connection = (
"keep-alive"
);
"Content-Length" = (
32
);
"Content-Type" = (
"application/json"
);
Date = (
"Fri, 30 Mar 2018 10:41:03 GMT"
);
Server = (
"meinheld/0.6.1"
);
Via = (
"1.1 vegur"
);
"X-Powered-By" = (
Flask
);
"X-Processed-Time" = (
0
);
} }
(Fetch Start) 2018-03-30 10:41:03 +0000
(Domain Lookup Start) 2018-03-30 10:41:03 +0000
(Domain Lookup End) 2018-03-30 10:41:03 +0000
(Connect Start) 2018-03-30 10:41:03 +0000
(Secure Connection Start) (null)
(Secure Connection End) (null)
(Connect End) 2018-03-30 10:41:03 +0000
(Request Start) 2018-03-30 10:41:03 +0000
(Request End) 2018-03-30 10:41:03 +0000
(Response Start) 2018-03-30 10:41:03 +0000
(Response End) 2018-03-30 10:41:03 +0000
(Protocol Name) http/1.1
(Proxy Connection) NO
(Reused Connection) NO
(Fetch Type) Network Load
)
-----------------------------------
timeline = Timeline: { "Latency": 0.677 secs, "Request Duration": 0.678 secs, "Serialization Duration": 0.000 secs, "Total Duration": 0.678 secs }
上面输出了很多很多的东西，我们来具体看看都有什么?
DefaultDataResponse
这个响应结果是Alamofire提供的一个结构体，我们看一下源码：
/// The URL request sent to the server.
public let request: URLRequest?
/// The server's response to the URL request.
public let response: HTTPURLResponse?
/// The data returned by the server.
public let data: Data?
/// The error encountered while executing or validating the request.
public let error: Error?
/// The timeline of the complete lifecycle of the request.
public let timeline: Timeline
var _metrics: AnyObject?
DefaultDataResponse结构体定义了上面这几个属性：
reqeuest就是你定义的请求
reponse是响应结果
data是服务器返回给我们的数据
error是执行请求和验证结果时候的错误
timeline是该请求从请求到收到结果的一条时间线
_metrics是iOS10及以后提供的一个时间线的属性，和timeline大同小异，所以你要使用的话必须是支持iOS10以后的版本才能使用
/// 这样写就没有问题了
if #available(iOS 10, *) {
print("metrics = ", defaultResponse.metrics)
}
不过除了response响应处理以外我们还有4种其他的响应处理方式：
- responseJSON
- reponseData
- responseString
- responsePropertyList
在我们的程序里，大多数用到的是第一和第二种。
responseString响应处理的是字符串
responsePropertyList响应处理的是plist(类似于responseJSON)都是转换成Any类型。
responseJSON是将服务器返回数据序列化为json然后转换成Any.
reponseData是将服务器返回数据序列化为Data然后转换成Data.
Alamofire强烈建议我们使用这四种去做处理，不建议我们使用DefaultResponse，这个就不纠结了我们用下面四种已经足够了。
先看responseData:
Alamofire.request(url2).responseData(completionHandler: { response in
print(response.result.value)
})
输出：Optional(32 bytes)
我们看到了reponse.result，这个result是啥？我们点进去看看
enum Result<Value> {
case success(Value)
case failure(Error)
public var value: Value? {
switch self {
case .success(let value):
return value
case .failure:
return nil
}
}
}
/// 源码我没有展示完 我们只看关于这篇文章的
Reust是一个泛型的枚举，当我们使用responseData的使用，Value就会被转换为Data，当我们调用response.result.vlaue的时候就会看到输出了"Optional(32 bytes)"这很明显是Data类型,然后我们把它解析出来看看是什么:
let url2 = "http://httpbin.org/ip"
Alamofire.request(url2).responseData(completionHandler: { response in
guard let value = response.result.value else { return }
let result = try? JSONSerialization.jsonObject(with: value, options: [])
guard let res = result else { return }
let dictionary = res as! [String: Any]
print("dictionary = ", dictionary)
})
输出：dictionary = ["origin": 101.81.57.239]
这就是responseData的简单用法了.
下面我们来看responseJSON怎么使用：
Alamofire.request(url2).responseJSON { response in
print(response.result.value)
}
输出： Optional({ origin = "101.81.57.239";})
很明显它是一个JSON格式，这就是Alamofire序列化为JSON的好处。为什么我们使用Reulst，因为它是Alamofire序列化好服务器给我们使用的一个属性，所以我们不用再去做序列化的操作，直接使用就好了。下面我们转化成字典类型:
Alamofire.request(url2).responseJSON { response in
guard let value = response.result.value else { return }
let dictionary = value as! [String: Any]
print("dictionary = ", dictionary)
}
输出：dictionary = ["origin": 101.81.57.239]
和responseData是一样的输出结果，但是比responseData要少两步, 所以如果你的程序后台返回的是JSON格式的数据，你直接使用responseJSON要比responseData要方便很多。
--以此来记录 Usage Alamofire ^ _^ --
