HttpListenerResponse.KeepAlive Proprietà

Definizione

Ottiene o imposta un valore che indica se il server richiede una connessione permanente.Gets or sets a value indicating whether the server requests a persistent connection.

public:
 property bool KeepAlive { bool get(); void set(bool value); };
public bool KeepAlive { get; set; }
member this.KeepAlive : bool with get, set
Public Property KeepAlive As Boolean

Valore della proprietà

true se il server richiede una connessione permanente; in caso contrario, false.true if the server requests a persistent connection; otherwise, false. Il valore predefinito è true.The default is true.

Eccezioni

Questo oggetto è chiuso.This object is closed.

Esempi

Nell'esempio di codice riportato di seguito viene illustrata l'impostazione del valore di questa proprietà.The following code example demonstrates setting the value of this property.


// When the client is not authenticated, there is no Identity.
if (context.User == null)
{
    message.Append ("<HTML><BODY><p> Hello local user! </p></BODY></HTML>");
}
else
{
    // Get the requester's identity.
    System.Security.Principal.WindowsIdentity identity = WindowsIdentity.GetCurrent();
    // Construct the response body.
    message.AppendFormat ("<HTML><BODY><p> Hello {0}!<br/>", 
        identity.Name);
    message.AppendFormat ("You were authenticated using {0}.</p>", 
        identity.AuthenticationType);
    message.Append ("</BODY></HTML>");
}

// Configure the response.
HttpListenerResponse response = context.Response;

// Use the encoding from the response if one has been set.
// Otherwise, use UTF8.
System.Text.Encoding encoding = response.ContentEncoding;
if (encoding == null)
{
    encoding = System.Text.Encoding.UTF8;
    response.ContentEncoding = encoding;
}
byte[] buffer = encoding.GetBytes (message.ToString ());
response.ContentLength64 = buffer.Length;
response.StatusCode = (int) HttpStatusCode.OK;
response.StatusDescription = "OK";
response.ProtocolVersion = new Version ("1.1");
// Don't keep the TCP connection alive; 
// We don't expect multiple requests from the same client.
response.KeepAlive = false;
// Write the response body.
System.IO.Stream stream = response.OutputStream;
stream.Write(buffer, 0, buffer.Length);

' When the client is not authenticated, there is no Identity.
If context.User Is Nothing Then
    message.Append("<HTML><BODY><p> Hello local user! </p></BODY></HTML>")
Else
    ' Get the requester's identity.
    Dim identity As System.Security.Principal.WindowsIdentity = WindowsIdentity.GetCurrent()
    ' Construct the response body.
    message.AppendFormat("<HTML><BODY><p> Hello {0}!<br/>", identity.Name)
    message.AppendFormat("You were authenticated using {0}.</p>", identity.AuthenticationType)
    message.Append("</BODY></HTML>")
End If

' Configure the response.
Dim response As HttpListenerResponse = context.Response

' Use the encoding from the response if one has been set.
' Otherwise, use UTF8.
Dim encoding As System.Text.Encoding = response.ContentEncoding
If encoding Is Nothing Then
    encoding = System.Text.Encoding.UTF8
    response.ContentEncoding = encoding
End If
Dim buffer() As Byte = encoding.GetBytes(message.ToString())
response.ContentLength64 = buffer.Length
response.StatusCode = CInt(HttpStatusCode.OK)
response.StatusDescription = "OK"
response.ProtocolVersion = New Version("1.1")
' Don't keep the TCP connection alive
' We don't expect multiple requests from the same client.
response.KeepAlive = False
' Write the response body.
Dim stream As System.IO.Stream = response.OutputStream
stream.Write(buffer, 0, buffer.Length)

Commenti

Se un client HTTP e un server si aspettano di scambiare dati più volte in un breve periodo di tempo, una connessione permanente velocizza le comunicazioni consentendo loro di evitare il sovraccarico necessario per aprire e chiudere una connessione TCP per ogni messaggio.If an HTTP client and server expect to exchange data multiple times in a short period, a persistent connection speeds up their communications by allowing them to avoid the overhead required to open and close a TCP connection for each message. Le connessioni permanenti sono ampiamente utilizzate nelle comunicazioni tra i Web browser moderni e i server Web.Persistent connections are in widespread use in communications between modern Web browsers and Web servers.

Le connessioni permanenti sono descritte in dettaglio nella specifica del protocollo HTTP/1.1 (RFC 2616) disponibile nel sito Web dell'editor RTF (https://www.rfc-editor.org/).Persistent connections are described in detail in the HTTP/1.1 protocol specification (RFC 2616) available at the RTF Editor Web site (https://www.rfc-editor.org/).

Si applica a

Vedi anche