Is File readable or writeable : File Command « File Stream « C# / C Sharp






  1. C# / C Sharp
  2. File Stream
  3. File Command

Is File readable or writeable

     

using System;
using System.Collections.Generic;
using System.Text;
using System.Security.AccessControl;
using System.IO;
using System.Security.Principal;

namespace Td.Additional.IO
{
    /// <summary>
    /// File facilities.
    /// </summary>
    public static class File
    {
        /// <summary>
        /// Determines whether the specified file is readable.
        /// </summary>
        /// <param name="filename">The filename.</param>
        /// <returns>
        ///   <c>true</c> if the specified file is readable; otherwise, <c>false</c>.
        /// </returns>
        public static bool IsReadable(string filename)
        {
            WindowsIdentity principal = WindowsIdentity.GetCurrent();
            if (System.IO.File.Exists(filename))
            {
                FileInfo fi = new FileInfo(filename);
                AuthorizationRuleCollection acl =
                    fi.GetAccessControl().GetAccessRules(true, true, typeof(SecurityIdentifier));
                for (int i = 0; i < acl.Count; i++)
                {
                    System.Security.AccessControl.FileSystemAccessRule rule = (System.Security.AccessControl.FileSystemAccessRule)acl[i];
                    if (principal.User.Equals(rule.IdentityReference))
                    {
                        if (System.Security.AccessControl.AccessControlType.Deny.Equals
                        (rule.AccessControlType))
                        {
                            if ((((int)FileSystemRights.Read) & (int)rule.FileSystemRights) == (int)(FileSystemRights.Read))
                                return false;
                        }
                        else if (System.Security.AccessControl.AccessControlType.Allow.Equals
                        (rule.AccessControlType))
                        {
                            if ((((int)FileSystemRights.Read) & (int)rule.FileSystemRights) == (int)(FileSystemRights.Read))
                                return true;
                        }
                    }
                }
            }
            else
            {
                return false;
            }
            return false;
        }

        /// <summary>
        /// Determines whether the specified file is writeable.
        /// </summary>
        /// <param name="filename">The filename.</param>
        /// <returns>
        ///   <c>true</c> if the specified file is writeable; otherwise, <c>false</c>.
        /// </returns>
        public static bool IsWriteable(string filename)
        {
            WindowsIdentity principal = WindowsIdentity.GetCurrent();
            if (System.IO.File.Exists(filename))
            {
                FileInfo fi = new FileInfo(filename);
                if (fi.IsReadOnly)
                    return false;
                AuthorizationRuleCollection acl =
                    fi.GetAccessControl().GetAccessRules(true, true, typeof(SecurityIdentifier));
                for (int i = 0; i < acl.Count; i++)
                {
                    System.Security.AccessControl.FileSystemAccessRule rule = (System.Security.AccessControl.FileSystemAccessRule)acl[i];
                    if (principal.User.Equals(rule.IdentityReference))
                    {
                        if (System.Security.AccessControl.AccessControlType.Deny.Equals
                        (rule.AccessControlType))
                        {
                            if ((((int)FileSystemRights.Write) & (int)rule.FileSystemRights) == (int)(FileSystemRights.Write))
                                return false;
                        }
                        else if (System.Security.AccessControl.AccessControlType.Allow.Equals
                        (rule.AccessControlType))
                        {
                            if ((((int)FileSystemRights.Write) & (int)rule.FileSystemRights) == (int)(FileSystemRights.Write))
                                return true;
                        }
                    }
                }
            }
            else
            {
                return false;
            }
            return false;
        }

    }
}








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