WebPermission Class

WebPermission provides a set of methods and properties to control access to Internet resources. You can use a WebPermission to provide either restricted or unrestricted access to your resource, based on the PermissionState that is set when the WebPermission is created.

Create a WebPermission instance by calling its constructor using one of the following sets of parameters:

• No parameters. The default PermissionState is None.

• A PermissionState. Specify either Unrestricted to allow any URI to be used in the target class, or None to allow access only to URIs that you specify through the use of the AddPermission method.

• A NetworkAccess value and a URI string. The specified URI has permissions granted by the NetworkAccess value.

• A NetworkAccess specifier and URI regular expression.

The ConnectList and AcceptList hold the URIs to which you have granted access permission. To add a URI to either of these lists, use AddPermission. If you pass Accept as the NetworkAccess parameter, the URI will be added to the AcceptList. WebPermission will allow connections to your target class with URIs matching the AcceptList.

Caution
To Deny access to an Internet resource, you must Deny access to all the possible paths to that resource. A better approach is to allow access to the specific resource only. For more information about this subject, refer to the Using the Deny Method topic.

Note
You need to Deny access using only the resource canonical path. There is no need to use all the path's syntactical variations.

Note
User name and default port information is stripped from the Uri before the comparison with the regular expression argument that is supplied to the WebPermission(NetworkAccess, Regex) constructor. If the regular expression contains user information or the default port number, then all incoming Uris will fail to match the regular expression.

The following example demonstrates how to create a new instance of WebPermission using a Regex. Additional hosts are added to the connect and accept list of WebPermission. Finally, the connect and accept list are displayed to the console.

    //  Create a Regex that accepts all URLs containing the host fragment www.contoso.com.
    Regex myRegex = new Regex(@"http://www\.contoso\.com/.*");

    // Create a WebPermission that gives permissions to all the hosts containing the same host fragment.
    WebPermission myWebPermission = new WebPermission(NetworkAccess.Connect,myRegex);

    //Add connect privileges for a www.adventure-works.com.
    myWebPermission.AddPermission(NetworkAccess.Connect,"http://www.adventure-works.com");

    //Add accept privileges for www.alpineskihouse.com.
    myWebPermission.AddPermission(NetworkAccess.Accept, "http://www.alpineskihouse.com/");

    // Check whether all callers higher in the call stack have been granted the permission.
    myWebPermission.Demand();

    // Get all the URIs with Connect permission.
    IEnumerator myConnectEnum = myWebPermission.ConnectList;
    Console.WriteLine("\nThe 'URIs' with 'Connect' permission are :\n");
    while (myConnectEnum.MoveNext())
    {Console.WriteLine("\t" + myConnectEnum.Current);}

    // Get all the URIs with Accept permission.	  
    IEnumerator myAcceptEnum = myWebPermission.AcceptList;
    Console.WriteLine("\n\nThe 'URIs' with 'Accept' permission is :\n");

    while (myAcceptEnum.MoveNext())
      {Console.WriteLine("\t" + myAcceptEnum.Current);}

.NET Framework

.NET Framework Client Profile

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference