Add generic pagination on generic repository #1304

src/AzureIoTHub.Portal.Infrastructure/Repositories/GenericRepository.cs

@@ -7,7 +7,10 @@ namespace AzureIoTHub.Portal.Infrastructure.Repositories
     using Domain.Base;
     using Microsoft.EntityFrameworkCore;
     using System.Collections.Generic;
+    using System.Linq.Expressions;
     using System.Threading.Tasks;
+    using Shared.Models.v1._0;
+    using System.Linq.Dynamic.Core;
 
     public class GenericRepository<T> : IRepository<T> where T : EntityBase
     {
@@ -50,5 +53,32 @@ public void Delete(object id)
 
             _ = this.context.Set<T>().Remove(existing);
         }
+
+        public async Task<PaginatedResult<T>> GetPaginatedListAsync(
+            int pageNumber,
+            int pageSize,
+            string[]? orderBy = null,
+            Expression<Func<T, bool>>? expression = null,
+            CancellationToken cancellationToken = default
+            )
+        {
+            IQueryable<T> query = this.context.Set<T>();
+            if (expression != null) query = query.Where(expression);
+
+            var ordering = orderBy?.Any() == true ? string.Join(",", orderBy) : null;
+
+            query = !string.IsNullOrWhiteSpace(ordering) ? query.OrderBy(ordering) : query.OrderBy(a => a.Id);
+
+            var count = await query
+                .AsNoTracking()
+                .CountAsync(cancellationToken: cancellationToken);
+
+            var items = await query
+                .Skip(pageNumber * pageSize)
+                .Take(pageSize)
+                .ToDynamicListAsync<T>(cancellationToken: cancellationToken);
+
+            return new PaginatedResult<T>(items, count, pageNumber, pageSize);
+        }
     }
 }

src/AzureIoTHub.Portal.Tests.Unit/Infrastructure/Repositories/GenericRepositoryTests.cs

@@ -4,10 +4,13 @@
 namespace AzureIoTHub.Portal.Tests.Unit.Infrastructure.Repositories
 {
     using System;
+    using System.Collections.Generic;
+    using System.Linq;
     using System.Threading.Tasks;
     using AzureIoTHub.Portal.Domain.Entities;
     using AzureIoTHub.Portal.Infrastructure.Repositories;
     using AzureIoTHub.Portal.Tests.Unit.UnitTests.Bases;
+    using FluentAssertions;
     using Microsoft.EntityFrameworkCore;
     using Moq;
     using NUnit.Framework;
@@ -150,5 +153,84 @@ public async Task DeleteTest()
             // Assert
             Assert.IsNull(context.Set<DeviceModelProperty>().Find(entityId));
         }
+
+
+
+        [Test]
+        public async Task GetPaginatedListAsync_CustomFilter_ExpectedPageReturned()
+        {
+            // Arrange
+            var context = SetupDbContext();
+
+            await context.AddRangeAsync(new List<DeviceTag>
+            {
+                new()
+                {
+                    Id = "device_tag_01",
+                    Label = "Location 1",
+                    Required = false,
+                    Searchable = true
+                },
+                new()
+                {
+                    Id = "device_tag_02",
+                    Label = "Location 2",
+                    Required = true,
+                    Searchable = true
+                },
+                new()
+                {
+                    Id = "device_tag_03",
+                    Label = "Machine",
+                    Required = true,
+                    Searchable = true
+                },
+                new()
+                {
+                    Id = "device_tag_04",
+                    Label = "Location",
+                    Required = false,
+                    Searchable = false
+                },
+            });
+
+            _ = await context.SaveChangesAsync();
+
+            var instance = new GenericRepository<DeviceTag>(context);
+
+            // Order by label desc
+            var orderBy = new[] { $"{nameof(DeviceTag.Label)} desc" };
+
+            // Filter only tags with labels containing "location" and are searchable
+            var deviceTagPredicate = PredicateBuilder.True<DeviceTag>()
+                .And(tag => tag.Label.ToLowerInvariant().Contains("location"))
+                .And(tag => tag.Searchable);
+
+            // Act
+            var result = await instance.GetPaginatedListAsync(0, 10, orderBy, deviceTagPredicate);
+
+            // Assert
+            _ = result.Data.Count.Should().Be(2);
+            _ = result.TotalCount.Should().Be(2);
+            _ = result.PageSize.Should().Be(10);
+            _ = result.HasNextPage.Should().BeFalse();
+            _ = result.HasPreviousPage.Should().BeFalse();
+            _ = result.CurrentPage.Should().Be(0);
+            _ = result.TotalPages.Should().Be(1);
+
+            var firstDeviceTag = result.Data.First();
+
+            _ = firstDeviceTag.Id.Should().Be("device_tag_02");
+            _ = firstDeviceTag.Label.Should().Be("Location 2");
+            _ = firstDeviceTag.Required.Should().BeTrue();
+            _ = firstDeviceTag.Searchable.Should().BeTrue();
+
+            var secondDeviceTag = result.Data.Skip(1).First();
+
+            _ = secondDeviceTag.Id.Should().Be("device_tag_01");
+            _ = secondDeviceTag.Label.Should().Be("Location 1");
+            _ = secondDeviceTag.Required.Should().BeFalse();
+            _ = secondDeviceTag.Searchable.Should().BeTrue();
+        }
     }
 }

src/AzureIoTHub.Portal/Shared/Models/v1.0/PaginatedResult.cs

@@ -30,6 +30,6 @@ public PaginatedResult(List<T> data = default, int count = 0, int page = 0, int
 
         public bool HasPreviousPage => CurrentPage > 0;
 
-        public bool HasNextPage => CurrentPage < TotalPages;
+        public bool HasNextPage => CurrentPage < (TotalPages - 1);
     }
 }

src/AzureIoTHubPortal.Domain/IRepository.cs

@@ -4,8 +4,10 @@
 namespace AzureIoTHub.Portal.Domain
 {
     using System.Collections.Generic;
+    using System.Linq.Expressions;
     using System.Threading.Tasks;
     using Base;
+    using Portal.Shared.Models.v1._0;
 
     public interface IRepository<T> where T : EntityBase
     {
@@ -18,5 +20,7 @@ public interface IRepository<T> where T : EntityBase
         void Update(T obj);
 
         void Delete(object id);
+
+        Task<PaginatedResult<T>> GetPaginatedListAsync(int pageNumber, int pageSize, string[]? orderBy = null, Expression<Func<T, bool>>? expression = null, CancellationToken cancellationToken = default);
     }
 }