WebHeaderCollection.IsRestricted Method (String, Boolean)
.NET Framework (current version)
Tests whether the specified HTTP header can be set for the request or the response.
Assembly: System (in System.dll)
Public Shared Function IsRestricted ( headerName As String, response As Boolean ) As Boolean
Parameters
- headerName
-
Type:
System.String
The header to test.
- response
-
Type:
System.Boolean
Does the Framework test the response or the request?
| Exception | Condition |
|---|---|
| ArgumentNullException | headerName is null or Empty. |
| ArgumentException | headerName contains invalid characters. |
The IsRestricted method returns true to indicate that a request or response header is restricted and must be set using properties instead of directly or is set by the system. The restricted headers are:
Accept
Connection
Content-Length
Content-Type
Date
Expect
Host
If-Modified-Since
Range
Referer
Transfer-Encoding
User-Agent
Proxy-Connection
The following example checks the IsRestricted property to see if any request headers are prohibited from being set.
Public Shared Sub Main() Try 'Create a web request for "www.msn.com". Dim myHttpWebRequest As HttpWebRequest = CType(WebRequest.Create("http://www.msn.com"), HttpWebRequest) 'Get the associated response for the above request. Dim myHttpWebResponse As HttpWebResponse = CType(myHttpWebRequest.GetResponse(), HttpWebResponse) 'Get the headers associated with the response. Dim myWebHeaderCollection As WebHeaderCollection = myHttpWebResponse.Headers 'Check if the first response header is restricted. dim i as integer for i =0 to myWebHeaderCollection.Count-1 If WebHeaderCollection.IsRestricted(myWebHeaderCollection.AllKeys(i)) Then Console.WriteLine("'{0}' is a restricted header", myWebHeaderCollection.AllKeys(i)) Else Console.WriteLine("'{0}' is not a restricted header", myWebHeaderCollection.AllKeys(i)) End If next myHttpWebResponse.Close() Catch e As WebException Console.WriteLine(e.Message) If e.Status = WebExceptionStatus.ProtocolError Then Console.WriteLine("Status Code : {0}", CType(e.Response, HttpWebResponse).StatusCode) Console.WriteLine("Status Description : {0}", CType(e.Response, HttpWebResponse).StatusDescription) Console.WriteLine("Server : {0}", CType(e.Response, HttpWebResponse).Server) End If Catch e As Exception Console.WriteLine(e.Message) End Try End Sub 'Main
.NET Framework
Available since 2.0
Available since 2.0
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