Get Website Permission with Powershell - powershell

Question

I am trying to figure out how to get the well known Website Permission Lists with Powershell. I tried several methods. The best solution seems to me to try something like $spWeb.RoleAssignments but this delivers me not only the users and groups with ist permissions on the spweb. I also get the roleassignments from the unique lists and libraries on the website.
Do you have suggestions how can I filter to check if a user has, for example, read permission on the spweb (without regarding the lists and subwebs)?
My target is to check the spweb and ist subwebs and unique lists and libraries step by step for a user(group) like "NT AUTHORITY\Authenticated Users". Then I want to remove the roleassignment and add a new roleassignment with a group of my colleagues, so that not everybody can see the content. The uniqe permission structure should remain.

Answer 1

You could check if a user has specific permission level using SPWeb.DoesUserHavePermissions method:
public bool DoesUserHavePermissions(
string login,
SPBasePermissions permissionMask
)
SPWeb.DoesUserHavePermissions method (String, SPBasePermissions)
using (SPSite site = new SPSite("http://sp/"))
{
using (SPWeb web = site.OpenWeb())
{
// Make sure the current user can enumerate permissions.
if (web.DoesUserHavePermissions(SPBasePermissions.EnumeratePermissions))
{
// Specify the permission to check.
SPBasePermissions permissionToCheck = SPBasePermissions.ViewListItems;
Console.WriteLine("The following users have {0} permission:", permissionToCheck);
// Check the permissions of users who are explicitly assigned permissions.
SPUserCollection users = web.Users;
foreach (SPUser user in users)
{
string login = user.LoginName;
if (web.DoesUserHavePermissions(login, permissionToCheck))
{
Console.WriteLine(login);
}
}
}
}
}
Console.ReadLine();