我在iBooks上读了苹果的编程语言Swift,但不知道如何在Swift中发出HTTP请求(类似cURL)。我需要导入Obj-C类还是只需要导入默认库?或者不能基于原生Swift代码进行HTTP请求?
当前回答
基本的Swift 3+解决方案
guard let url = URL(string: "http://www.stackoverflow.com") else { return }
let task = URLSession.shared.dataTask(with: url) { data, response, error in
guard let data = data, error == nil else { return }
print(NSString(data: data, encoding: String.Encoding.utf8.rawValue))
}
task.resume()
其他回答
下面是在Linux上使用Swift进行HTTP请求的从头到尾的说明。
首先创建一个SwiftPM包
mkdir swift-http && cd swift-http && swift package init --type executable
然后替换。/Sources/swift-http/main.swift 代码如下:
import Foundation
import FoundationNetworking
let sema = DispatchSemaphore(value: 0)
URLSession.shared.dataTask(with: URL(string: "http://numbersapi.com/42")!) {(data, response, error) in
print(String(data: data!, encoding: .utf8) ?? String(describing: error))
sema.signal()
}.resume()
sema.wait()
然后运行代码
swift run
输出的例子:
[6/6] Build complete!
42 is the answer to the Ultimate Question of Life, the Universe, and Everything.
注意:使用DispatchSemaphore是为了使程序在得到响应之前不会退出。
你也可以这样做:
import Foundation
import FoundationNetworking
var done = false
URLSession.shared.dataTask(with: URL(string: "http://numbersapi.com/42")!) {(data, response, error) in
print(String(data: data!, encoding: .utf8) ?? String(describing: error))
done = true
}.resume()
while !done { Thread.sleep(forTimeInterval: 1) }
另一个选择是Alamofire库,它提供了可链请求/响应方法。
https://github.com/Alamofire/Alamofire
提出请求
import Alamofire
Alamofire.request(.GET, "http://httpbin.org/get")
响应处理
Alamofire.request(.GET, "http://httpbin.org/get", parameters: ["foo": "bar"])
.response { request, response, data, error in
print(request)
print(response)
print(error)
}
下面是一个非常简单的Swift 4在操场上的例子:
import UIKit
// run asynchronously in a playground
import PlaygroundSupport
PlaygroundPage.current.needsIndefiniteExecution = true
// create a url
let url = URL(string: "http://www.stackoverflow.com")
// create a data task
let task = URLSession.shared.dataTask(with: url!) { (data, response, error) in
if error != nil {
print("there's a problem")
}
print(String(data: data!, encoding: String.Encoding.utf8) ?? "")
}
//running the task w/ resume
task.resume()
为了让XCUITest在异步请求完成之前停止测试完成,使用这个(可能会减少100超时):
func test_api() {
let url = URL(string: "https://jsonplaceholder.typicode.com/posts/42")!
let exp = expectation(description: "Waiting for data")
let task = URLSession.shared.dataTask(with: url) {(data, response, error) in
guard let data = data else { return }
print(String(data: data, encoding: .utf8)!)
exp.fulfill()
}
task.resume()
XCTWaiter.wait(for: [exp], timeout: 100)
}
更新:Xcode 13.0和Swift 5+
获取HTTP请求
let url = URL(string: "URL HERE")! //PUT Your URL
var request = URLRequest(url: url)
request.httpMethod = "GET"
let task = URLSession.shared.dataTask(with: request) { data, response, error in
guard let safeData = data,
let response = response as? HTTPURLResponse,
error == nil else { // check for fundamental networking error
print("error", error ?? "Unknown error")
delegate?.onError(error!)
return
}
guard (200 ... 299) ~= response.statusCode else { // check for http errors
print("statusCode should be 2xx, but is \(response.statusCode)")
print("response = \(response)")
return
}
let responseString = String(data: safeData, encoding: .utf8)
print("Response String = \(responseString)")
}
task.resume()
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