HttpWebRequest.Abort Metode
Definisi
Penting
Beberapa informasi terkait produk prarilis yang dapat diubah secara signifikan sebelum dirilis. Microsoft tidak memberikan jaminan, tersirat maupun tersurat, sehubungan dengan informasi yang diberikan di sini.
Membatalkan permintaan ke sumber daya Internet.
public:
override void Abort();
public override void Abort ();
override this.Abort : unit -> unit
Public Overrides Sub Abort ()
Contoh
Dalam kasus permintaan asinkron, adalah tanggung jawab aplikasi klien untuk menerapkan mekanisme waktu habisnya sendiri. Contoh kode berikut menunjukkan cara melakukan ini.
#using <System.dll>
using namespace System;
using namespace System::Net;
using namespace System::IO;
using namespace System::Text;
using namespace System::Threading;
public ref class RequestState
{
private:
// This class stores the State of the request.
const int BUFFER_SIZE;
public:
StringBuilder^ requestData;
array<Byte>^BufferRead;
HttpWebRequest^ request;
HttpWebResponse^ response;
Stream^ streamResponse;
RequestState()
: BUFFER_SIZE( 1024 )
{
BufferRead = gcnew array<Byte>(BUFFER_SIZE);
requestData = gcnew StringBuilder( "" );
request = nullptr;
streamResponse = nullptr;
}
};
ref class HttpWebRequest_BeginGetResponse
{
public:
static ManualResetEvent^ allDone = gcnew ManualResetEvent( false );
literal int BUFFER_SIZE = 1024;
literal int DefaultTimeOut = 120000; // 2 minute timeout
// Abort the request if the timer fires.
static void TimeoutCallback( Object^ state, bool timedOut )
{
if ( timedOut )
{
HttpWebRequest^ request = dynamic_cast<HttpWebRequest^>(state);
if ( request != nullptr )
{
request->Abort();
}
}
}
static void RespCallback( IAsyncResult^ asynchronousResult )
{
try
{
// State of request is asynchronous.
RequestState^ myRequestState = dynamic_cast<RequestState^>(asynchronousResult->AsyncState);
HttpWebRequest^ myHttpWebRequest = myRequestState->request;
myRequestState->response = dynamic_cast<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, gcnew 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();
}
static void ReadCallBack( IAsyncResult^ asyncResult )
{
try
{
RequestState^ myRequestState = dynamic_cast<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, gcnew 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();
}
};
int main()
{
try
{
// Create a HttpWebrequest object to the desired URL.
HttpWebRequest^ myHttpWebRequest = dynamic_cast<HttpWebRequest^>(WebRequest::Create( "http://www.contoso.com" ));
/**
* If you are behind a firewall and you do not have your browser proxy setup
* you need to use the following proxy creation code.
// Create a proxy object.
WebProxy* myProxy = new WebProxy();
// Associate a new Uri object to the _wProxy object, using the proxy address
// selected by the user.
myProxy.Address = new Uri(S"http://myproxy");
// Finally, initialize the Web request object proxy property with the _wProxy
// object.
myHttpWebRequest.Proxy=myProxy;
***/
// Create an instance of the RequestState and assign the previous myHttpWebRequest
// object to its request field.
RequestState^ myRequestState = gcnew RequestState;
myRequestState->request = myHttpWebRequest;
// Start the asynchronous request.
IAsyncResult^ result = dynamic_cast<IAsyncResult^>(myHttpWebRequest->BeginGetResponse( gcnew AsyncCallback( HttpWebRequest_BeginGetResponse::RespCallback ), myRequestState ));
// this line impliments the timeout, if there is a timeout, the callback fires and the request becomes aborted
ThreadPool::RegisterWaitForSingleObject( result->AsyncWaitHandle, gcnew WaitOrTimerCallback( HttpWebRequest_BeginGetResponse::TimeoutCallback ), myHttpWebRequest, HttpWebRequest_BeginGetResponse::DefaultTimeOut, true );
// The response came in the allowed time. The work processing will happen in the
// callback function.
HttpWebRequest_BeginGetResponse::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();
}
}
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");
/**
* If you are behind a firewall and you do not have your browser proxy setup
* you need to use the following proxy creation code.
// Create a proxy object.
WebProxy myProxy = new WebProxy();
// Associate a new Uri object to the _wProxy object, using the proxy address
// selected by the user.
myProxy.Address = new Uri("http://myproxy");
// Finally, initialize the Web request object proxy property with the _wProxy
// object.
myHttpWebRequest.Proxy=myProxy;
***/
// 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();
}
Imports System.Net
Imports System.IO
Imports System.Text
Imports System.Threading
Public Class RequestState
' This class stores the State of the request.
Private BUFFER_SIZE As Integer = 1024
Public requestData As StringBuilder
Public BufferRead() As Byte
Public request As HttpWebRequest
Public response As HttpWebResponse
Public streamResponse As Stream
Public Sub New()
BufferRead = New Byte(BUFFER_SIZE) {}
requestData = New StringBuilder("")
request = Nothing
streamResponse = Nothing
End Sub
End Class
Class HttpWebRequest_BeginGetResponse
Public Shared allDone As New ManualResetEvent(False)
Private BUFFER_SIZE As Integer = 1024
Private DefaultTimeout As Integer = 2 * 60 * 1000
' 2 minutes timeout
' Abort the request if the timer fires.
Private Shared Sub TimeoutCallback(state As Object, timedOut As Boolean)
If timedOut Then
Dim request As HttpWebRequest = state
If Not (request Is Nothing) Then
request.Abort()
End If
End If
End Sub
Shared Sub Main()
Try
' Create a HttpWebrequest object to the desired URL.
Dim myHttpWebRequest As HttpWebRequest = WebRequest.Create("http://www.contoso.com")
' Create an instance of the RequestState and assign the previous myHttpWebRequest
' object to its request field.
Dim myRequestState As New RequestState()
myRequestState.request = myHttpWebRequest
Dim myResponse As New HttpWebRequest_BeginGetResponse()
' Start the asynchronous request.
Dim result As IAsyncResult = CType(myHttpWebRequest.BeginGetResponse(New AsyncCallback(AddressOf RespCallback), myRequestState), IAsyncResult)
' this line implements the timeout, if there is a timeout, the callback fires and the request aborts.
ThreadPool.RegisterWaitForSingleObject(result.AsyncWaitHandle, New WaitOrTimerCallback(AddressOf TimeoutCallback), myHttpWebRequest, myResponse.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 e As WebException
Console.WriteLine(ControlChars.Lf + "Main Exception raised!")
Console.WriteLine(ControlChars.Lf + "Message:{0}", e.Message)
Console.WriteLine(ControlChars.Lf + "Status:{0}", e.Status)
Console.WriteLine("Press any key to continue..........")
Catch e As Exception
Console.WriteLine(ControlChars.Lf + "Main Exception raised!")
Console.WriteLine("Source :{0} ", e.Source)
Console.WriteLine("Message :{0} ", e.Message)
Console.WriteLine("Press any key to continue..........")
Console.Read()
End Try
End Sub
Private Shared Sub RespCallback(asynchronousResult As IAsyncResult)
Try
' State of request is asynchronous.
Dim myRequestState As RequestState = CType(asynchronousResult.AsyncState, RequestState)
Dim myHttpWebRequest As HttpWebRequest = myRequestState.request
myRequestState.response = CType(myHttpWebRequest.EndGetResponse(asynchronousResult), HttpWebResponse)
' Read the response into a Stream object.
Dim responseStream As Stream = myRequestState.response.GetResponseStream()
myRequestState.streamResponse = responseStream
' Begin the Reading of the contents of the HTML page and print it to the console.
Dim asynchronousInputRead As IAsyncResult = responseStream.BeginRead(myRequestState.BufferRead, 0, 1024, New AsyncCallback(AddressOf ReadCallBack), myRequestState)
Return
Catch e As WebException
Console.WriteLine(ControlChars.Lf + "RespCallback Exception raised!")
Console.WriteLine(ControlChars.Lf + "Message:{0}", e.Message)
Console.WriteLine(ControlChars.Lf + "Status:{0}", e.Status)
End Try
allDone.Set()
End Sub
Private Shared Sub ReadCallBack(asyncResult As IAsyncResult)
Try
Dim myRequestState As RequestState = CType(asyncResult.AsyncState, RequestState)
Dim responseStream As Stream = myRequestState.streamResponse
Dim read As Integer = responseStream.EndRead(asyncResult)
' Read the HTML page and then print it to the console.
If read > 0 Then
myRequestState.requestData.Append(Encoding.ASCII.GetString(myRequestState.BufferRead, 0, read))
Dim asynchronousResult As IAsyncResult = responseStream.BeginRead(myRequestState.BufferRead, 0, 1024, New AsyncCallback(AddressOf ReadCallBack), myRequestState)
Return
Else
Console.WriteLine(ControlChars.Lf + "The contents of the Html page are : ")
If myRequestState.requestData.Length > 1 Then
Dim stringContent As String
stringContent = myRequestState.requestData.ToString()
Console.WriteLine(stringContent)
End If
Console.WriteLine("Press any key to continue..........")
Console.ReadLine()
responseStream.Close()
End If
Catch e As WebException
Console.WriteLine(ControlChars.Lf + "ReadCallBack Exception raised!")
Console.WriteLine(ControlChars.Lf + "Message:{0}", e.Message)
Console.WriteLine(ControlChars.Lf + "Status:{0}", e.Status)
End Try
allDone.Set()
End Sub
End Class
Keterangan
Hati
WebRequest
, HttpWebRequest
, ServicePoint
, dan WebClient
usang, dan Anda tidak boleh menggunakannya untuk pengembangan baru. Gunakan HttpClient sebagai gantinya.
Metode Abort membatalkan permintaan ke sumber daya. Setelah permintaan dibatalkan, memanggil metode GetResponse, BeginGetResponse, EndGetResponse, GetRequestStream, BeginGetRequestStream, atau EndGetRequestStream menyebabkan WebException dengan properti Status diatur ke RequestCanceled.
Metode Abort akan secara sinkron menjalankan panggilan balik yang ditentukan ke metode BeginGetRequestStream atau BeginGetResponse jika metode Abort dipanggil saat salah satu operasi ini luar biasa. Hal ini dapat menyebabkan potensi masalah kebuntuan.
Nota
Anggota ini mengeluarkan informasi pelacakan saat Anda mengaktifkan pelacakan jaringan di aplikasi Anda. Untuk informasi selengkapnya, lihat Network Tracing.
Berlaku untuk
Saran dan Komentar
https://aka.ms/ContentUserFeedback.
Segera hadir: Sepanjang tahun 2024 kami akan menghentikan penggunaan GitHub Issues sebagai mekanisme umpan balik untuk konten dan menggantinya dengan sistem umpan balik baru. Untuk mengetahui informasi selengkapnya, lihat:Kirim dan lihat umpan balik untuk