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
在Swift 4.1和Xcode 9.4.1中。
JSON POST方法示例。要检查互联网连接,从https://developer.apple.com/library/archive/samplecode/Reachability/Introduction/Intro.html#//apple_ref/doc/uid/DTS40007324-Intro-DontLinkElementID_2添加Reachability.h & .m文件
func yourFunctionName {
//Check internet connection
let networkReachability = Reachability.forInternetConnection()
let networkStatus:Int = (networkReachability?.currentReachabilityStatus())!.rawValue
print(networkStatus)
if networkStatus == NotReachable.rawValue {
let msg = SharedClass.sharedInstance.noNetMsg//Message
//Call alert from shared class
SharedClass.sharedInstance.alert(view: self, title: "", message: msg)
} else {
//Call spinner from shared class
SharedClass.sharedInstance.activityIndicator(view: self.view)//Play spinner
let parameters = "Your parameters here"
var request = URLRequest(url: URL(string: url)!)
request.setValue("application/x-www-form-urlencoded", forHTTPHeaderField: "Content-Type")
request.httpMethod = "POST"
print("URL : \(request)")
request.httpBody = parameters.data(using: .utf8)
let task = URLSession.shared.dataTask(with: request) { data, response, error in guard let data = data, error == nil else { // check for fundamental networking error
//Stop spinner
SharedClass.sharedInstance.stopActivityIndicator() //Stop spinner
//Print error in alert
SharedClass.sharedInstance.alert(view: self, title: "", message: "\(String(describing: error!.localizedDescription))")
return
}
SharedClass.sharedInstance.stopActivityIndicator() //Stop spinner
if let httpStatus = response as? HTTPURLResponse, httpStatus.statusCode != 200 { // check for http errors
print("statusCode should be 200, but is \(httpStatus.statusCode)")
print("response = \(String(describing: response))")
}
do {
let response = try JSONSerialization.jsonObject(with: data, options: []) as? [String: AnyObject]
print(response!)
//Your code here
} catch let error as NSError {
print(error)
}
}
task.resume()
}
}
如果你有兴趣在SharedClass中使用这个函数
//My shared class
import UIKit
class SharedClass: NSObject {
static let sharedInstance = SharedClass()
func postRequestFunction(apiName: String , parameters: String, onCompletion: @escaping (_ success: Bool, _ error: Error?, _ result: [String: Any]?)->()) {
var URL = "your URL here/index.php/***?"
URL = URL.replacingOccurrences(of: "***", with: apiName)
var request = URLRequest(url: URL(string: URL)!)
request.setValue("application/x-www-form-urlencoded", forHTTPHeaderField: "Content-Type")
request.httpMethod = "POST"
print("shared URL : \(request)")
request.httpBody = parameters.data(using: .utf8)
var returnRes:[String:Any] = [:]
let task = URLSession.shared.dataTask(with: request) { data, response, error in
if let error = error {
onCompletion(false, error, nil)
} else {
guard let data = data else {
onCompletion(false, error, nil)
return
}
if let httpStatus = response as? HTTPURLResponse, httpStatus.statusCode == 200 {
do {
returnRes = try JSONSerialization.jsonObject(with: data, options: []) as! [String : Any]
onCompletion(true, nil, returnRes)
} catch let error as NSError {
onCompletion(false, error, nil)
}
} else {
onCompletion(false, error, nil)
}
}
}
task.resume()
}
private override init() {
}
最后像这样调用这个函数....
SharedClass.sharedInstance.postRequestFunction(apiName: "Your API name", parameters: parameters) { (success, error, result) in
print(result!)
if success {
//Your code here
} else {
print(error?.localizedDescription ?? "")
}
}
其他回答
我调用json登录按钮点击
@IBAction func loginClicked(sender : AnyObject) {
var request = NSMutableURLRequest(URL: NSURL(string: kLoginURL)) // Here, kLogin contains the Login API.
var session = NSURLSession.sharedSession()
request.HTTPMethod = "POST"
var err: NSError?
request.HTTPBody = NSJSONSerialization.dataWithJSONObject(self.criteriaDic(), options: nil, error: &err) // This Line fills the web service with required parameters.
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("application/json", forHTTPHeaderField: "Accept")
var task = session.dataTaskWithRequest(request, completionHandler: {data, response, error -> Void in
var strData = NSString(data: data, encoding: NSUTF8StringEncoding)
var err1: NSError?
var json2 = NSJSONSerialization.JSONObjectWithData(strData.dataUsingEncoding(NSUTF8StringEncoding), options: .MutableLeaves, error:&err1 ) as NSDictionary
println("json2 :\(json2)")
if(err) {
println(err!.localizedDescription)
}
else {
var success = json2["success"] as? Int
println("Success: \(success)")
}
})
task.resume()
}
在这里,我为参数创建了一个单独的字典。
var params = ["format":"json", "MobileType":"IOS","MIN":"f8d16d98ad12acdbbe1de647414495ec","UserName":emailTxtField.text,"PWD":passwordTxtField.text,"SigninVia":"SH"]as NSDictionary
return params
}
// You can add your own sets of parameter here.
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()
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) }
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()
你可以使用URL URLRequest URLSession或者NSURLConnection就像你在Objective-C中通常做的那样。注意,对于iOS 7.0及更高版本,URLSession是首选。
使用URLSession
初始化URL对象和URLSession中的URLSessionDataTask。然后使用resume()运行任务。
let url = URL(string: "http://www.stackoverflow.com")!
let task = URLSession.shared.dataTask(with: url) {(data, response, error) in
guard let data = data else { return }
print(String(data: data, encoding: .utf8)!)
}
task.resume()
使用NSURLConnection
首先,初始化URL和URLRequest:
let url = URL(string: "http://www.stackoverflow.com")!
var request = URLRequest(url: url)
request.httpMethod = "POST"
然后,你可以异步加载请求:
NSURLConnection.sendAsynchronousRequest(request, queue: OperationQueue.main) {(response, data, error) in
guard let data = data else { return }
print(String(data: data, encoding: .utf8)!)
}
或者你可以初始化一个NSURLConnection:
let connection = NSURLConnection(request: request, delegate:nil, startImmediately: true)
只是要确保将委托设置为nil以外的东西,并使用委托方法处理接收到的响应和数据。
要了解更多细节,请查看NSURLConnectionDataDelegate协议的文档
在Xcode操场上测试
如果你想在Xcode游乐场上尝试这段代码,添加import PlaygroundSupport到你的游乐场,以及下面的调用:
PlaygroundPage.current.needsIndefiniteExecution = true
这将允许你在操场上使用异步代码。
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