सी #: टाइमआउट

Question

क्या .NET में यह करने के लिए सबसे अच्छा तरीका है के साथ एक URL डाउनलोड किया? मैं हमेशा मैं क्या Dispose() करने की जरूरत है (या using के साथ रैप) भूल जाते हैं।

संपादित करें: एक लंबे समय के WebRequest उपयोग करने के बाद, मैं बाहर WebClient अनुकूलित करने के बारे में पाया गया। काफी बेहतर।

Answer 1

थॉमस लेवेस्क की टिप्पणी here के बाद, वहाँ एक सरल और अधिक सामान्य समाधान है।

हम टाइमआउट समर्थन के साथ WebClient सबक्लास बनाते हैं, और हमें WebClient की भलाई मिलती है।

public class WebClientWithTimeout : WebClient 
{ 
    private readonly int timeoutMilliseconds; 
    public WebClientWithTimeout(int timeoutMilliseconds) 
    { 
    this.timeoutMilliseconds = timeoutMilliseconds; 
    } 

    protected override WebRequest GetWebRequest(Uri address) 
    { 
    var result = base.GetWebRequest(address); 
    result.Timeout = timeoutMilliseconds; 
    return result; 
    } 
} 

नमूना उपयोग:

public string GetRequest(Uri uri, int timeoutMilliseconds) 
{ 
    using (var client = new WebClientWithTimeout(timeoutMilliseconds)) 
    { 
    return client.DownloadString(); 
    } 
} 

Answer 2

यहाँ मैं क्या उपयोग है, यह काम करने के लिए लगता है, लेकिन अगर यह सबसे अच्छा तरीका है मैं नहीं जानता:

public string GetRequest(Uri uri, int timeoutMilliseconds) 
{ 
    var request = System.Net.WebRequest.Create(uri); 
    request.Timeout = timeoutMilliseconds; 
    using (var response = request.GetResponse()) 
    using (var stream = response.GetResponseStream()) 
    using (var reader = new System.IO.StreamReader(stream)) 
    { 
     return reader.ReadToEnd(); 
    } 
} 

Answer 3

भागो System.Net.WebClient एक अलग धागे में, यह मारने के लिए एक टाइमर सेट आपके अधिकतम समय के बाद।

Answer 4

syncronous रास्ता:

var request = HttpWebRequest.Create("http://www.contoso.com"); 
request.Timeout = 50000; 
using (var response = request.GetResponse()) 
{ 
    //your code here 
} 

तुम भी अतुल्यकालिक तरह से हो सकता है:

using System; 
using System.Net; 
using System.IO; 
using System.Text; 
using System.Threading; 


public class RequestState 
{ 
    // This class stores the State of the request. 
    const int BUFFER_SIZE = 1024; 
    public StringBuilder requestData; 
    public byte[] BufferRead; 
    public HttpWebRequest request; 
    public HttpWebResponse response; 
    public Stream streamResponse; 
    public RequestState() 
    { 
    BufferRead = new byte[BUFFER_SIZE]; 
    requestData = new StringBuilder(""); 
    request = null; 
    streamResponse = null; 
    } 
} 

class HttpWebRequest_BeginGetResponse 
{ 
    public static ManualResetEvent allDone = new ManualResetEvent(false); 
    const int BUFFER_SIZE = 1024; 
    const int DefaultTimeout = 2 * 60 * 1000; // 2 minutes timeout 

    // Abort the request if the timer fires. 
    private static void TimeoutCallback(object state, bool timedOut) 
    { 
     if (timedOut) 
     { 
      HttpWebRequest request = state as HttpWebRequest; 
      if (request != null) 
      { 
       request.Abort(); 
      } 
     } 
    } 

    static void Main() 
    { 

     try 
     { 
      // Create a HttpWebrequest object to the desired URL. 
      HttpWebRequest myHttpWebRequest = (HttpWebRequest)WebRequest.Create("http://www.contoso.com"); 
      myHttpWebRequest.ReadWriteTimeout = DefaultTimeout; 


      // Create an instance of the RequestState and assign the previous myHttpWebRequest 
      // object to its request field. 
      RequestState myRequestState = new RequestState(); 
      myRequestState.request = myHttpWebRequest; 


      // Start the asynchronous request. 
      IAsyncResult result = 
       (IAsyncResult)myHttpWebRequest.BeginGetResponse(new AsyncCallback(RespCallback), myRequestState); 

      // this line implements the timeout, if there is a timeout, the callback fires and the request becomes aborted 
      ThreadPool.RegisterWaitForSingleObject(result.AsyncWaitHandle, new WaitOrTimerCallback(TimeoutCallback), myHttpWebRequest, DefaultTimeout, true); 

      // The response came in the allowed time. The work processing will happen in the 
      // callback function. 
      allDone.WaitOne(); 

      // Release the HttpWebResponse resource. 
      myRequestState.response.Close(); 
     } 
     catch (WebException e) 
     { 
      Console.WriteLine("\nMain Exception raised!"); 
      Console.WriteLine("\nMessage:{0}", e.Message); 
      Console.WriteLine("\nStatus:{0}", e.Status); 
      Console.WriteLine("Press any key to continue.........."); 
     } 
     catch (Exception e) 
     { 
      Console.WriteLine("\nMain Exception raised!"); 
      Console.WriteLine("Source :{0} ", e.Source); 
      Console.WriteLine("Message :{0} ", e.Message); 
      Console.WriteLine("Press any key to continue.........."); 
      Console.Read(); 
     } 
    } 
    private static void RespCallback(IAsyncResult asynchronousResult) 
    { 
     try 
     { 
      // State of request is asynchronous. 
      RequestState myRequestState = (RequestState)asynchronousResult.AsyncState; 
      HttpWebRequest myHttpWebRequest = myRequestState.request; 
      myRequestState.response = (HttpWebResponse)myHttpWebRequest.EndGetResponse(asynchronousResult); 

      // Read the response into a Stream object. 
      Stream responseStream = myRequestState.response.GetResponseStream(); 
      myRequestState.streamResponse = responseStream; 

      // Begin the Reading of the contents of the HTML page and print it to the console. 
      IAsyncResult asynchronousInputRead = responseStream.BeginRead(myRequestState.BufferRead, 0, BUFFER_SIZE, new AsyncCallback(ReadCallBack), myRequestState); 
      return; 
     } 
     catch (WebException e) 
     { 
      Console.WriteLine("\nRespCallback Exception raised!"); 
      Console.WriteLine("\nMessage:{0}", e.Message); 
      Console.WriteLine("\nStatus:{0}", e.Status); 
     } 
     allDone.Set(); 
    } 
    private static void ReadCallBack(IAsyncResult asyncResult) 
    { 
     try 
     { 

      RequestState myRequestState = (RequestState)asyncResult.AsyncState; 
      Stream responseStream = myRequestState.streamResponse; 
      int read = responseStream.EndRead(asyncResult); 
      // Read the HTML page and then print it to the console. 
      if (read > 0) 
      { 
       myRequestState.requestData.Append(Encoding.ASCII.GetString(myRequestState.BufferRead, 0, read)); 
       IAsyncResult asynchronousResult = responseStream.BeginRead(myRequestState.BufferRead, 0, BUFFER_SIZE, new AsyncCallback(ReadCallBack), myRequestState); 
       return; 
      } 
      else 
      { 
       Console.WriteLine("\nThe contents of the Html page are : "); 
       if (myRequestState.requestData.Length > 1) 
       { 
        string stringContent; 
        stringContent = myRequestState.requestData.ToString(); 
        Console.WriteLine(stringContent); 
       } 
       Console.WriteLine("Press any key to continue.........."); 
       Console.ReadLine(); 

       responseStream.Close(); 
      } 

     } 
     catch (WebException e) 
     { 
      Console.WriteLine("\nReadCallBack Exception raised!"); 
      Console.WriteLine("\nMessage:{0}", e.Message); 
      Console.WriteLine("\nStatus:{0}", e.Status); 
     } 
     allDone.Set(); 

    } 
}