HttpListenerRequest.UrlReferrer Property
Definition
Important
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Gets the Uniform Resource Identifier (URI) of the resource that referred the client to the server.
public:
property Uri ^ UrlReferrer { Uri ^ get(); };public Uri? UrlReferrer { get; }public Uri UrlReferrer { get; }member this.UrlReferrer : UriPublic ReadOnly Property UrlReferrer As UriProperty Value
A Uri object that contains the text of the request's Referer header, or null if the header was not included in the request.
Examples
The following code example demonstrates using this property.
public static void ShowRequestProperties1 (HttpListenerRequest request)
{
// Display the MIME types that can be used in the response.
string[] types = request.AcceptTypes;
if (types != null)
{
Console.WriteLine("Acceptable MIME types:");
foreach (string s in types)
{
Console.WriteLine(s);
}
}
// Display the language preferences for the response.
types = request.UserLanguages;
if (types != null)
{
Console.WriteLine("Acceptable natural languages:");
foreach (string l in types)
{
Console.WriteLine(l);
}
}
// Display the URL used by the client.
Console.WriteLine("URL: {0}", request.Url.OriginalString);
Console.WriteLine("Raw URL: {0}", request.RawUrl);
Console.WriteLine("Query: {0}", request.QueryString);
// Display the referring URI.
Console.WriteLine("Referred by: {0}", request.UrlReferrer);
//Display the HTTP method.
Console.WriteLine("HTTP Method: {0}", request.HttpMethod);
//Display the host information specified by the client;
Console.WriteLine("Host name: {0}", request.UserHostName);
Console.WriteLine("Host address: {0}", request.UserHostAddress);
Console.WriteLine("User agent: {0}", request.UserAgent);
}
Public Shared Sub ShowRequestProperties1(ByVal request As HttpListenerRequest)
' Display the MIME types that can be used in the response.
Dim types As String() = request.AcceptTypes
If types IsNot Nothing Then
Console.WriteLine("Acceptable MIME types:")
For Each s As String In types
Console.WriteLine(s)
Next
End If
' Display the language preferences for the response.
types = request.UserLanguages
If types IsNot Nothing Then
Console.WriteLine("Acceptable natural languages:")
For Each l As String In types
Console.WriteLine(l)
Next
End If
' Display the URL used by the client.
Console.WriteLine("URL: {0}", request.Url.OriginalString)
Console.WriteLine("Raw URL: {0}", request.RawUrl)
Console.WriteLine("Query: {0}", request.QueryString)
' Display the referring URI.
Console.WriteLine("Referred by: {0}", request.UrlReferrer)
' Display the HTTP method.
Console.WriteLine("HTTP Method: {0}", request.HttpMethod)
' Display the host information specified by the client.
Console.WriteLine("Host name: {0}", request.UserHostName)
Console.WriteLine("Host address: {0}", request.UserHostAddress)
Console.WriteLine("User agent: {0}", request.UserAgent)
End Sub
Remarks
If a client has followed a hyperlink to the requested URI, its request might contain a Referrer header that identifies the URI of the resource that contained the hyperlink.
Clients can falsify or choose not to present a Referer header. Therefore, while the UrlReferrer property can be useful for identifying basic trends in Web traffic; you should not use it as part of an authorization scheme to control access to data.
For a complete list of request headers, see the HttpRequestHeader enumeration.
The UrlReferrer is null when there is no Referrer header in the request or when the Referrer header is present in the request but does not parse to a valid Uri.
