Refactor PermissionsChecker

Used `IRepository.GetAggregateAsync` method with a newly created `MemberPermissionsSpecification` to reduce a number of db queries.

AdvancedTodoList.Core/Dtos/PermissionsAggregate.cs

@@ -0,0 +1,13 @@
+using AdvancedTodoList.Core.Models.TodoLists.Members;
+
+namespace AdvancedTodoList.Core.Dtos;
+
+/// <summary>
+/// Represents an aggregate of a to-do list member with a role.
+/// </summary>
+public record PermissionsAggregate(RoleEssentials? Role);
+
+/// <summary>
+/// Represents role's permissions and priority.
+/// </summary>
+public record RoleEssentials(int Priority, RolePermissions Permissions);

AdvancedTodoList.Infrastructure/Services/Auth/PermissionsChecker.cs

@@ -1,12 +1,9 @@
-using AdvancedTodoList.Core.Models;
+using AdvancedTodoList.Core.Dtos;
+using AdvancedTodoList.Core.Models;
 using AdvancedTodoList.Core.Models.TodoLists.Members;
 using AdvancedTodoList.Core.Repositories;
 using AdvancedTodoList.Core.Services.Auth;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
+using AdvancedTodoList.Infrastructure.Specifications;
 
 namespace AdvancedTodoList.Infrastructure.Services.Auth;
 
@@ -47,15 +44,12 @@ public async Task<bool> IsMemberOfListAsync(string userId, string todoListId)
 	/// </returns>
 	public async Task<bool> HasPermissionAsync(string userId, string todoListId, Func<RolePermissions, bool> permission)
 	{
-		var member = await _membersRepository.FindAsync(todoListId, userId);
+		MemberPermissionsSpecification specification = new(todoListId, userId);
+		var member = await _membersRepository.GetAggregateAsync<PermissionsAggregate>(specification);
 		// User is not a member or has no role - return false
-		if (member == null || member.RoleId == null) return false;
+		if (member == null || member.Role == null) return false;
 
-		// Check user's permissions
-		var role = await _rolesRepository.GetByIdAsync(member.RoleId.Value);
-		if (role == null) return false;
-
-		return permission(role.Permissions);
+		return permission(member.Role.Permissions);
 	}
 
 	/// <summary>
@@ -100,19 +94,18 @@ Task<bool> IPermissionsChecker.CanTouchEntityAsync<TEntity, TKey>(string userId,
 	/// </returns>
 	public async Task<bool> HasPermissionOverRoleAsync(string userId, string todoListId, int roleId, Func<RolePermissions, bool> permission)
 	{
-		var member = await _membersRepository.FindAsync(todoListId, userId);
-		// User is not a member or has no role - return false
-		if (member == null || member.RoleId == null) return false;
+		MemberPermissionsSpecification specification = new(todoListId, userId);
+		var member = await _membersRepository.GetAggregateAsync<PermissionsAggregate>(specification);
 
-		// Check if user has a permission
-		var userRole = await _rolesRepository.GetByIdAsync(member.RoleId.Value);
-		if (userRole == null || !permission(userRole.Permissions)) return false;
+		// User is not a member, has no role or permission - return false
+		if (member == null || member.Role == null || !permission(member.Role.Permissions)) 
+			return false;
 
 		// Get other role
-		var role = await _rolesRepository.GetByIdAsync(roleId) ?? 
+		var role = await _rolesRepository.GetByIdAsync(roleId) ??
 			throw new ArgumentException("Role with 'roleId' was not found", nameof(roleId));
 
 		// Check if user has a higher priority
-		return userRole.Priority < role.Priority;
+		return member.Role.Priority < role.Priority;
 	}
 }

AdvancedTodoList.Infrastructure/Specifications/MemberPermissionsSpecification.cs

@@ -0,0 +1,43 @@
+using AdvancedTodoList.Core.Models.TodoLists.Members;
+using AdvancedTodoList.Core.Specifications;
+using AdvancedTodoList.Infrastructure.Services.Auth;
+using System.Linq.Expressions;
+
+namespace AdvancedTodoList.Infrastructure.Specifications;
+
+/// <summary>
+/// Represents a specification for obtaining an aggregate containg the to-do list member
+/// and his/her/their role, used in <see cref="PermissionsChecker" />.
+/// </summary>
+/// <param name="todoListId">ID of the to-do list.</param>
+/// <param name="userId">ID of the user.</param>
+public class MemberPermissionsSpecification(string todoListId, string userId) : ISpecification<TodoListMember>
+{
+	/// <summary>
+	/// Gets the to-do list ID.
+	/// </summary>
+	public string TodoListId { get; } = todoListId;
+	/// <summary>
+	/// Gets the user ID.
+	/// </summary>
+	public string UserId { get; } = userId;
+
+	/// <summary>
+	/// Gets the criteria expression that defines the filtering conditions.
+	/// </summary>
+	public Expression<Func<TodoListMember, bool>> Criteria =>
+		x => x.TodoListId == TodoListId && x.UserId == UserId;
+
+	/// <summary>
+	/// Gets the list of include expressions specifying a to-do list role to be included in the query results.
+	/// </summary>
+	public List<Expression<Func<TodoListMember, object?>>> Includes =>
+	[
+		x => x.Role
+	];
+
+	/// <summary>
+	/// Gets the list of include strings specifying related entities to be included in the query results.
+	/// </summary>
+	public List<string> IncludeStrings { get; } = [];
+}

AdvancedTodoList.UnitTests/Specifications/MemberPermissionsSpecificationTests.cs

@@ -0,0 +1,50 @@
+using AdvancedTodoList.Core.Models.TodoLists.Members;
+using AdvancedTodoList.Infrastructure.Specifications;
+
+namespace AdvancedTodoList.UnitTests.Specifications;
+
+public class MemberPermissionsSpecificationTests
+{
+	[Test]
+	public void Criteria_ValidTodoListIdAndUserId_ReturnsTrue()
+	{
+		// Arrange
+		const string todoListId = "TodoId";
+		const string userId = "UserId";
+		TodoListMember member = new()
+		{
+			TodoListId = todoListId,
+			UserId = userId
+		};
+		MemberPermissionsSpecification specification = new(todoListId, userId);
+		var criteria = specification.Criteria.Compile();
+
+		// Act
+		bool result = criteria(member);
+
+		// Arrange
+		Assert.That(result, Is.True);
+	}
+
+	[Test]
+	[TestCase("TodoListId", "invalid")]
+	[TestCase("invalid", "UserId")]
+	[TestCase("invalid", "invalid")]
+	public void Criteria_InvalidTodoListIdAndUserIdPairs_ReturnsFalse(string todoListId, string userId)
+	{
+		// Arrange
+		TodoListMember member = new()
+		{
+			TodoListId = "TodoListId",
+			UserId = "UserId"
+		};
+		MemberPermissionsSpecification specification = new(todoListId, userId);
+		var criteria = specification.Criteria.Compile();
+
+		// Act
+		bool result = criteria(member);
+
+		// Arrange
+		Assert.That(result, Is.False);
+	}
+}