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
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) }
其他回答
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)
}
下面给出了一个“GET”请求示例。
let urlString = "YOUR_GET_URL"
let yourURL = URL(string: urlstring)
let dataTask = URLSession.shared.dataTask(with: yourURL) { (data, response, error) in
do {
let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers)
print("json --- \(json)")
}catch let err {
print("err---\(err.localizedDescription)")
}
}
dataTask.resume()
细节
Xcode 9.2, Swift 4 Xcode 10.2.1 (10E1001)
Info.plist
NSApp传输安全
添加到info plist:
<key>NSAppTransportSecurity</key>
<dict>
<key>NSAllowsArbitraryLoads</key>
<true/>
</dict>
Alamofire样本
Alamofire
import Alamofire
class AlamofireDataManager {
fileprivate let queue: DispatchQueue
init(queue: DispatchQueue) { self.queue = queue }
private func createError(message: String, code: Int) -> Error {
return NSError(domain: "dataManager", code: code, userInfo: ["message": message ])
}
private func make(session: URLSession = URLSession.shared, request: URLRequest, closure: ((Result<[String: Any]>) -> Void)?) {
Alamofire.request(request).responseJSON { response in
let complete: (Result<[String: Any]>) ->() = { result in DispatchQueue.main.async { closure?(result) } }
switch response.result {
case .success(let value): complete(.success(value as! [String: Any]))
case .failure(let error): complete(.failure(error))
}
}
}
func searchRequest(term: String, closure: ((Result<[String: Any]>) -> Void)?) {
guard let url = URL(string: "https://itunes.apple.com/search?term=\(term.replacingOccurrences(of: " ", with: "+"))") else { return }
let request = URLRequest(url: url)
make(request: request) { response in closure?(response) }
}
}
Alamofire样品的使用
private lazy var alamofireDataManager = AlamofireDataManager(queue: DispatchQueue(label: "DataManager.queue", qos: .utility))
//.........
alamofireDataManager.searchRequest(term: "jack johnson") { result in
print(result.value ?? "no data")
print(result.error ?? "no error")
}
URLSession样本
import Foundation
class DataManager {
fileprivate let queue: DispatchQueue
init(queue: DispatchQueue) { self.queue = queue }
private func createError(message: String, code: Int) -> Error {
return NSError(domain: "dataManager", code: code, userInfo: ["message": message ])
}
private func make(session: URLSession = URLSession.shared, request: URLRequest, closure: ((_ json: [String: Any]?, _ error: Error?)->Void)?) {
let task = session.dataTask(with: request) { [weak self] data, response, error in
self?.queue.async {
let complete: (_ json: [String: Any]?, _ error: Error?) ->() = { json, error in DispatchQueue.main.async { closure?(json, error) } }
guard let self = self, error == nil else { complete(nil, error); return }
guard let data = data else { complete(nil, self.createError(message: "No data", code: 999)); return }
do {
if let json = try JSONSerialization.jsonObject(with: data, options: .mutableContainers) as? [String: Any] {
complete(json, nil)
}
} catch let error { complete(nil, error); return }
}
}
task.resume()
}
func searchRequest(term: String, closure: ((_ json: [String: Any]?, _ error: Error?)->Void)?) {
let url = URL(string: "https://itunes.apple.com/search?term=\(term.replacingOccurrences(of: " ", with: "+"))")
let request = URLRequest(url: url!)
make(request: request) { json, error in closure?(json, error) }
}
}
URLSession示例的使用
private lazy var dataManager = DataManager(queue: DispatchQueue(label: "DataManager.queue", qos: .utility))
// .......
dataManager.searchRequest(term: "jack johnson") { json, error in
print(error ?? "nil")
print(json ?? "nil")
print("Update views")
}
结果
你可以使用Just,一个python-requests风格的HTTP库。
使用Just发送HTTP请求的示例:
// synchronous GET request with URL query a=1
let r = Just.get("https://httpbin.org/get", params:["a":1])
// asynchronous POST request with form value and file uploads
Just.post(
"http://justiceleauge.org/member/register",
data: ["username": "barryallen", "password":"ReverseF1ashSucks"],
files: ["profile_photo": .URL(fileURLWithPath:"flash.jpeg", nil)]
) { (r)
if (r.ok) { /* success! */ }
}
在这两种情况下,可以通过类似于python-request的方式访问请求r的结果:
r.ok // is the response successful?
r.statusCode // status code of response
r.content // response body as NSData?
r.text // response body as text?
r.json // response body parsed by NSJSONSerielization
你可以在这个操场上找到更多的例子
在操场上以同步模式使用这个库是Swift中最接近cURL的东西。
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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