streamlines the naming of the content/media permissions handlers

src/Umbraco.Web.BackOffice/Authorization/ContentPermissionsQueryStringHandler.cs

@@ -0,0 +1,109 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc.Controllers;
+using Microsoft.Extensions.Primitives;
+using System;
+using System.Threading.Tasks;
+using Umbraco.Core;
+using Umbraco.Core.Models;
+using Umbraco.Core.Security;
+using Umbraco.Core.Services;
+
+namespace Umbraco.Web.BackOffice.Authorization
+{
+
+    /// <summary>
+    /// Used to authorize if the user has the correct permission access to the content for the content id specified in a query string
+    /// </summary>
+    public class ContentPermissionsQueryStringHandler : AuthorizationHandler<ContentPermissionsQueryStringRequirement>
+    {
+        private readonly IBackOfficeSecurityAccessor _backofficeSecurityAccessor;
+        private readonly IHttpContextAccessor _httpContextAccessor;
+        private readonly IEntityService _entityService;
+        private readonly ContentPermissions _contentPermissions;
+
+        public ContentPermissionsQueryStringHandler(
+            IBackOfficeSecurityAccessor backofficeSecurityAccessor,
+            IHttpContextAccessor httpContextAccessor, 
+            IEntityService entityService,
+            ContentPermissions contentPermissions)
+        {
+            _backofficeSecurityAccessor = backofficeSecurityAccessor;
+            _httpContextAccessor = httpContextAccessor;
+            _entityService = entityService;
+            _contentPermissions = contentPermissions;
+        }
+
+        protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, ContentPermissionsQueryStringRequirement requirement)
+        {
+            int nodeId;
+            if (requirement.NodeId.HasValue == false)
+            {
+                StringValues routeVal;
+                foreach(var qs in requirement.QueryStringNames)
+                {
+                    if (_httpContextAccessor.HttpContext.Request.Query.TryGetValue(qs, out routeVal))
+                    {
+                        break;                        
+                    }
+                }
+
+                if (routeVal.Count == 0)
+                {
+                    throw new InvalidOperationException("No argument found for the current action with by names " + string.Join(", ", requirement.QueryStringNames));
+                }
+                
+                var argument = routeVal.ToString();
+                // if the argument is an int, it will parse and can be assigned to nodeId
+                // if might be a udi, so check that next
+                // otherwise treat it as a guid - unlikely we ever get here
+                if (int.TryParse(argument, out int parsedId))
+                {
+                    nodeId = parsedId;
+                }
+                else if (UdiParser.TryParse(argument, true, out var udi))
+                {
+                    nodeId = _entityService.GetId(udi).Result;
+                }
+                else
+                {
+                    Guid.TryParse(argument, out Guid key);
+                    nodeId = _entityService.GetId(key, UmbracoObjectTypes.Document).Result;
+                }
+            }
+            else
+            {
+                nodeId = requirement.NodeId.Value;
+            }
+
+            var permissionResult = _contentPermissions.CheckPermissions(nodeId,
+                _backofficeSecurityAccessor.BackOfficeSecurity.CurrentUser,                
+                out IContent contentItem,
+                new[] { requirement.PermissionToCheck });
+
+            if (permissionResult == ContentPermissions.ContentAccess.NotFound)
+            {
+                return null;
+            }
+
+            if (permissionResult == ContentPermissions.ContentAccess.Denied)
+            {
+                context.Fail();
+            }
+            else
+            {
+                context.Succeed(requirement);
+            }
+
+
+            if (contentItem != null)
+            {
+                //store the content item in request cache so it can be resolved in the controller without re-looking it up
+                _httpContextAccessor.HttpContext.Items[typeof(IContent).ToString()] = contentItem;
+            }
+
+            return Task.CompletedTask;
+        }
+
+    }
+}