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HttpListenerRequest.UrlReferrer Property

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Definition

Namespace:
System.Net
Assembly:
System.Net.HttpListener.dll
Assembly:
System.dll
Assembly:
netstandard.dll
Source:
HttpListenerRequest.cs
Source:
HttpListenerRequest.cs
Source:
HttpListenerRequest.cs

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 : Uri
Public ReadOnly Property UrlReferrer As Uri

Property Value

Uri

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.

Applies to

See also