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()
其他回答
我已经完成了HTTP请求两种方法GET和POST与JSON解析的方式:
在viewDidLoad ():
override func viewDidLoad() {
super.viewDidLoad()
makeGetRequest()
makePostRequest()
}
func makePostRequest(){
let urlPath: String = "http://www.swiftdeveloperblog.com/http-post-example-script/"
var url: NSURL = NSURL(string: urlPath)!
var request: NSMutableURLRequest = NSMutableURLRequest(URL: url)
request.HTTPMethod = "POST"
var stringPost="firstName=James&lastName=Bond" // Key and Value
let data = stringPost.dataUsingEncoding(NSUTF8StringEncoding)
request.timeoutInterval = 60
request.HTTPBody=data
request.HTTPShouldHandleCookies=false
let queue:NSOperationQueue = NSOperationQueue()
NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue(), completionHandler:{ (response:NSURLResponse!, data: NSData!, error: NSError!) -> Void in
var error: AutoreleasingUnsafeMutablePointer<NSError?> = nil
let jsonResult: NSDictionary! = NSJSONSerialization.JSONObjectWithData(data, options:NSJSONReadingOptions.MutableContainers, error: error) as? NSDictionary
if (jsonResult != nil) {
// Success
println(jsonResult)
let message = jsonResult["Message"] as! NSString
println(message)
}else {
// Failed
println("Failed")
}
})
}
func makeGetRequest(){
var url : String = "http://api.androidhive.info/contacts/"
var request : NSMutableURLRequest = NSMutableURLRequest()
request.URL = NSURL(string: url)
request.HTTPMethod = "GET"
request.timeoutInterval = 60
NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue(), completionHandler:{ (response:NSURLResponse!, data: NSData!, error: NSError!) -> Void in
var error: AutoreleasingUnsafeMutablePointer<NSError?> = nil
let jsonResult: NSDictionary! = NSJSONSerialization.JSONObjectWithData(data, options:NSJSONReadingOptions.MutableContainers, error: error) as? NSDictionary
if (jsonResult != nil) {
// Success
println(jsonResult)
let dataArray = jsonResult["contacts"] as! NSArray;
for item in dataArray { // loop through data items
let obj = item as! NSDictionary
for (key, value) in obj {
println("Key: \(key) - Value: \(value)")
let phone = obj["phone"] as! NSDictionary;
let mobile = phone["mobile"] as! NSString
println(mobile)
let home = phone["home"] as! NSString
println(home)
let office = phone["office"] as! NSString
println(office)
}
}
} else {
// Failed
println("Failed")
}
})
}
Done
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()
一个简单的Swift 2.0方法来发出HTTP GET请求
HTTP请求是异步的,因此需要一种方法从HTTP请求中获取返回值。这种方法使用通知器,分布在两个类中。
示例是使用网站http://www.example.com/handler.php?do=CheckUserJson&json=检查标识符令牌的用户名和密码,该文件名为handler.php,并且在do参数上有一个switch语句以获得RESTful方法。
在viewDidLoad中,我们设置了NotifierObserver,设置了json,并调用getHTTPRequest函数。它将返回函数checkedUsernameAndPassword和从http请求返回的参数。
override func viewDidLoad() {
super.viewDidLoad()
// setup the Notification observer to catch the result of check username and password
NSNotificationCenter.defaultCenter().addObserver(self, selector: "checkedUsernameAndPassword:", name: CHECK_USERNAME_AND_PASSWORD, object: nil)
let username = GlobalVariables.USER_NAME
let password = GlobalVariables.PASSWORD
// check username and password
if let jsonString = Utility.checkUsernameAndPasswordJson(username, password:password){
print("json string returned = \(jsonString)")
let url = CHECKUSERJSON+jsonString
// CHECKUSERJSON = http://www.example.com/handler.php?do=CheckUserJson&json=
// jsonString = {\"username\":\"demo\",\"password\":\"demo\"}"
// the php script handles a json request and returns a string identifier
Utility.getHTTPRequest(url,notifierId: CHECK_USERNAME_AND_PASSWORD)
// the returned identifier is sent to the checkedUsernaeAndPassword function when it becomes availabel.
}
}
在Utility.swift中有两个静态函数,首先用于编码json,然后执行HTTP调用。
static func checkUsernameAndPasswordJson(username: String, password: String) -> String?{
let para:NSMutableDictionary = NSMutableDictionary()
para.setValue("demo", forKey: "username")
para.setValue("demo", forKey: "password")
let jsonData: NSData
do{
jsonData = try NSJSONSerialization.dataWithJSONObject(para, options: NSJSONWritingOptions())
let jsonString = NSString(data: jsonData, encoding: NSUTF8StringEncoding) as! String
return jsonString
} catch _ {
print ("UH OOO")
return nil
}
}
和Http请求
static func getHTTPRequest (url:String , notifierId: String) -> Void{
let urlString = url
let config = NSURLSessionConfiguration.defaultSessionConfiguration()
let session = NSURLSession(configuration: config, delegate: nil, delegateQueue: nil)
let safeURL = urlString.stringByAddingPercentEncodingWithAllowedCharacters(NSCharacterSet.URLQueryAllowedCharacterSet())!
if let url = NSURL(string: safeURL){
let request = NSMutableURLRequest(URL: url)
request.HTTPMethod = "GET"
request.timeoutInterval = 60
let taskData = session.dataTaskWithRequest(request, completionHandler: {
(data:NSData?, response:NSURLResponse?, error:NSError?) -> Void in
if (data != nil) {
let result = NSString(data: data! , encoding: NSUTF8StringEncoding)
sendNotification (notifierId, message: String(result), num: 0)
}else{
sendNotification (notifierId, message: String(UTF8String: nil), num: -1) }
})
taskData.resume()
}else{
print("bad urlString = \(urlString)")
}
}
sendNotification函数完成了循环。注意,在观察者中,在选择器字符串的末尾有一个“:”。这允许通知在userInfo中携带有效负载。我给它一个String和Int。
static func sendNotification (key: String, message:String?, num: Int?){
NSNotificationCenter.defaultCenter().postNotificationName(
key,
object: nil,
userInfo: (["message": message!,
"num": "\(num!)"])
)
}
注意,使用HTTP是老式的,更喜欢HTTPS见我如何加载一个HTTP URL与应用程序传输安全启用在iOS 9?
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) }
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