Permissions Management

log.Info("Inheriting permissions");
//Inherit permissions if broken
rListitem.ResetRoleInheritance();
transList.ResetRoleInheritance();

log.Info("Now let's start breaking the permissions again");
// Break permissions
rListitem.BreakRoleInheritance(false, false);
transList.BreakRoleInheritance(false, false);
RoleAssignmentCollection collRoleAssign = destList.RoleAssignments;
context.ExecuteQuery();

collRoleAssign.Add(author, new RoleDefinitionBindingCollection(context){web.RoleDefinitions.GetByType(RoleType.Contributor)});
collRoleAssign.Add(editor, new RoleDefinitionBindingCollection(context){web.RoleDefinitions.GetByType(RoleType.Contributor)});

applog.LogInformation("Update finised for created by and modified by");

try{
FieldUserValue[] fldContributors = (FieldUserValue[])rListitem["Contributors"];

if(fldContributors != null)
{
applog.LogInformation($"{fldContributors.Length} Contributors found. Applying updates");
for (int i = 0; i < fldContributors.Length; i++) 
{ 
    try
    {
        var userInfoList = context.Site.RootWeb.SiteUserInfoList;
        var userInfo = userInfoList.GetItemById(fldContributors[i].LookupId);
        context.Load(userInfo,info => info.ContentType);
        context.ExecuteQuery();

        string userType = "Person";
        if(userInfo != null)
            userType = userInfo.ContentType.Name;

        if(userType == "Person" || userType == "DomainGroup")
        {
            var fldContributoruser = web.EnsureUser(fldContributors[i].LookupValue);
            if(fldContributors[i].LookupValue.ToString() != authorUser.LookupValue.ToString() || fldContributors[i].LookupValue.ToString() != modifiedUser.LookupValue.ToString())
            {
              collRoleAssign.Add(fldContributoruser, new RoleDefinitionBindingCollection(context){web.RoleDefinitions.GetByType(RoleType.Contributor)});
            }
            try
            {
            Group visitorsGroup = grpCollection.GetByName("<Group Name>");
            UserCollection collUser = visitorsGroup.Users;
            collUser.AddUser(fldContributoruser);

            context.Load(fldContributoruser);
            context.Load(visitorsGroup);
            context.ExecuteQuery();
            }catch(Exception ex8){applog.LogError($"Error at Visitors group Add: {ex8.Message}");}
        }
        else if(userType == "SharePointGroup")
        {
            var primaryGroup = grpCollection.GetByName(fldContributors[i].LookupValue);
            collRoleAssign.Add(primaryGroup, new RoleDefinitionBindingCollection(context){web.RoleDefinitions.GetByType(RoleType.Contributor)});
            rListitem.RoleAssignments.Add(primaryGroup, new RoleDefinitionBindingCollection(context){web.RoleDefinitions.GetByType(RoleType.Contributor)});
        } 
    }
    catch(Exception ex3)
    {applog.LogError($"Error at Contributor Creation: {ex3.Message}");}
}
applog.LogInformation("Contributors processing finished");