iOS基礎Networking處理

幾乎所有的APP都需要連網抓取／上傳資料的功能，這篇文章記錄networking基本的處理。

以dataTaskWithRequest取得網路連線

let url = NSURL(string: "https://itunes.apple.com/search?term=apple&media=software")
let urlRequest = NSURLRequest(URL: url!, cachePolicy: .ReturnCacheDataElseLoad, timeoutInterval: 30) 
let task = NSURLSession.sharedSession().dataTaskWithRequest(urlRequest) { 
    (data:NSData?, res:NSURLResponse?, err:NSError?) -> Void in 
    if let data = data { 
      let dataStr = NSString(data: data, encoding: NSUTF8StringEncoding) 
    } 
  } 
task.resume() 

首先得設定URL的字串，然後建立連線請求，這裡需要設定cache的使用方式和timeout的時間。以此例來說，假如cache己有先前的資料，則直接使用；而timeout設為30秒後觸發。

接著使用dataTaskWithRequest將連線抓取的資料做處理，這裡用到closure，我們可以把處理資料的部分寫成function，可增加使用上的彈性。最後記得執行task

dataTaskWithURL

let url = NSURL(string: "https://itunes.apple.com/search?term=apple&media=software") 
let task = NSURLSession.sharedSession().dataTaskWithURL(url!) { 
  data, res, err in
    if let data = data { 
      do { 
        let dic = try NSJSONSerialization.JSONObjectWithData(data, options: .MutableContainers) as! NSDictionary 
        let array = dic["results"] as! NSArray 

        for appDic in array { 
          print("trackName \(appDic["trackName"])") 
        } 
      } catch { 

      } 
    } 
} 
task.resume() 

這裡省略NSURLRequest，直接對NSURL做連線抓資料的動作
抓下來是是json格式的資料，所以我們得做序列化的動作並轉換成NSArray的型式
最後將results下所有trackName印出來

利用downloadTaskWithRequest將資料存在local端

let url = NSURL(string: "https://itunes.apple.com/search?term=apple&media=software") 
let urlRequest = NSURLRequest(URL: url!, cachePolicy: .ReturnCacheDataElseLoad, timeoutInterval: 30) 

let task = NSURLSession.sharedSession().downloadTaskWithRequest(urlRequest) { 
  (location:NSURL?, res:NSURLResponse?, err:NSError?) -> Void in  if let location = location { 
    let data = NSData(contentsOfURL: location) 
    if let data = data { 
      do { 
        let dic = try NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers) as! NSDictionary 
        let array = dic["results"] as! NSArray 

        for appDic in array { 
          print("trackName \(appDic["trackName"])") 
        } 
      } catch { } 
    } 
  } 
} 
task.resume()

這裡task的closure把資料存在location中，而location為local路徑，所以需要使用NSData存取。

NSURLSessionConfiguration

可以獨立設定URLSession的config，例如timeout和cache

let sessionConfiguration = NSURLSessionConfiguration.defaultSessionConfiguration() 
sessionConfiguration.timeoutIntervalForRequest = 1 
let session = NSURLSession(configuration: sessionConfiguration)

let url = NSURL(string: "https://itunes.apple.com/search?term=apple&media=software") 
let urlRequest = NSURLRequest(URL: url!) 
let task = session.dataTaskWithRequest(urlRequest) { 
  data, res, err in 

  // something to do 
} 
task.resume() 

利用NSURLSessionUploadTask上傳資料

let url = NSURL(string: "https://www.peter.com") 
let urlRequest = NSMutableURLRequest(URL: url!) 
urlRequest.HTTPMethod = "POST" 

let postStr = "name=peter&grade=99" 
let data = postStr.dataUsingEncoding(NSUTF8StringEncoding) 

let task = NSURLSession.sharedSession().uploadTaskWithRequest(urlRequest, fromData: data) { 
  returnData, res, err in 
    if let returnData = returnData { 
      do { 
        let dic = try NSJSONSerialization.JSONObjectWithData(returnData , options: .MutableContainers) as! NSDictionary 
        let status = dic["success"] as? NSNumber 
        if status!.intValue == 1 { 
          print("success") 
        } 
      } catch { 
      } 
    } 
} 
task.resume() 

先設定URLRequest的http method為post，再將想上傳的資料編碼為NSUTF8StringEncoding格式
接下來使用uploadTaskWithRequest上傳資料

利用NSURLSessionDataTask上傳資料

let url = NSURL(string: "https://www.peter.com") 
let urlRequest = NSMutableURLRequest(URL: url!) 
urlRequest.HTTPMethod = "POST" 

let postStr = "name=peter&grade=99" 
let data = postStr.dataUsingEncoding(NSUTF8StringEncoding) urlRequest.HTTPBody = data 

let task = NSURLSession.sharedSession().dataTaskWithRequest(urlRequest) { 
  returnData, res, err in 
    if let returnData = returnData { 
      do { 
        let dic = try NSJSONSerialization.JSONObjectWithData(returnData , options: NSJSONReadingOptions.MutableContainers) as! NSDictionary 
        let status = dic["success"] as? NSNumber 
        if status!.intValue == 1 { 
          print("success") 
        } 
      } catch { 
      } 
    } 
} 
task.resume() 

可以將資料放進NSURLRequest的HTTPBody裡並上傳

利用NSURLSessionUploadTask上傳json格式資料

let url = NSURL(string: "https://www.peter.com") 
let urlRequest = NSMutableURLRequest(URL: url!) 
urlRequest.HTTPMethod = "POST" 
urlRequest.setValue("application/json", forKey: "Content-Type")   
let dictionary = ["name": "penny", "grade":"77"] 

do { 
  let data = try  NSJSONSerialization.dataWithJSONObject(dictionary, options: []) 
  let task = NSURLSession.sharedSession().uploadTaskWithRequest(urlRequest, fromData: data) { 
    (returnData, res, err:NSError?) -> Void in
    // do something
  }
} catch {
  
}
task.resume()

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