PT-7293: Add a new Liquid 'where' filter to enable filtering collections

src/VirtoCommerce.NotificationsModule.LiquidRenderer/Filters/ArrayFilter.cs

@@ -0,0 +1,171 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using System.Linq.Expressions;
+using System.Reflection;
+using VirtoCommerce.Platform.Core.Common;
+
+namespace VirtoCommerce.NotificationsModule.LiquidRenderer.Filters
+{
+    public static class ArrayFilter
+    {
+        /// <summary>
+        /// Filter the elements of an array by a given condition
+        /// {% assign filtered = items | where: 'propertyName' '==' 'propertyValue' %}
+        /// </summary>
+        /// <param name="input"></param>
+        /// <param name="propertyName"></param>
+        /// <param name="operationName"></param>
+        /// <param name="propertyValue"></param>
+        /// <returns></returns>
+        /// <exception cref="ArgumentException"></exception>
+        public static object Where(object input, string propertyName, string operationName, string propertyValue)
+        {
+            if (input is not IEnumerable enumerable)
+            {
+                throw new ArgumentException("Input is not a collection", nameof(input));
+            }
+
+            var elementType = GetEnumerableElementType(enumerable.GetType());
+            var property = elementType.GetProperty(propertyName, BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance);
+
+            if (property is null)
+            {
+                throw new ArgumentException($"Unknown property '{propertyName}'", nameof(propertyName));
+            }
+
+            var parameterX = Expression.Parameter(elementType, "x");
+            var left = Expression.Property(parameterX, property);
+            var value = ParsePropertyValue(propertyValue, left.Type);
+            var right = Expression.Constant(value, left.Type);
+
+            BinaryExpression operation;
+
+            if (operationName.EqualsInvariant("=="))
+            {
+                operation = Expression.Equal(left, right);
+            }
+            else if (operationName.EqualsInvariant("!="))
+            {
+                operation = Expression.NotEqual(left, right);
+            }
+            else if (operationName.EqualsInvariant(">"))
+            {
+                operation = Expression.GreaterThan(left, right);
+            }
+            else if (operationName.EqualsInvariant(">="))
+            {
+                operation = Expression.GreaterThanOrEqual(left, right);
+            }
+            else if (operationName.EqualsInvariant("<"))
+            {
+                operation = Expression.LessThan(left, right);
+            }
+            else if (operationName.EqualsInvariant("<="))
+            {
+                operation = Expression.LessThanOrEqual(left, right);
+            }
+            else if (operationName.EqualsInvariant("contains"))
+            {
+                Expression expression;
+
+                if (property.PropertyType == typeof(string))
+                {
+                    var containsMethod = typeof(string).GetMethods().First(x => x.Name == "Contains");
+                    expression = Expression.Call(left, containsMethod, right);
+                }
+                else
+                {
+                    var containsMethod = typeof(Enumerable).GetMethods()
+                        .First(x => x.Name == "Contains" && x.GetParameters().Length == 2)
+                        .MakeGenericMethod(value.GetType());
+
+                    expression = Expression.Call(containsMethod, left, right);
+                }
+
+                operation = Expression.Equal(expression, Expression.Constant(true));
+            }
+            else
+            {
+                throw new ArgumentException($"Unknown operation '{operationName}'", nameof(operationName));
+            }
+
+            var delegateType = typeof(Func<,>).MakeGenericType(elementType, typeof(bool));
+
+            // Construct expression: Func<T, bool> = (x) => x.propertyName == propertyValue
+            var lambda = Expression.Lambda(delegateType, operation, parameterX);
+
+            // Find Queryable.Where(Expression<Func<TSource, bool>>) method
+            var whereMethod = typeof(Queryable).GetMethods()
+                .Where(x => x.Name == "Where")
+                .Select(x => new { M = x, P = x.GetParameters() })
+                .Where(x => x.P.Length == 2 &&
+                            x.P[0].ParameterType.IsGenericType &&
+                            x.P[0].ParameterType.GetGenericTypeDefinition() == typeof(IQueryable<>) &&
+                            x.P[1].ParameterType.IsGenericType &&
+                            x.P[1].ParameterType.GetGenericTypeDefinition() == typeof(Expression<>))
+                .Select(x => new { x.M, A = x.P[1].ParameterType.GetGenericArguments() })
+                .Where(x => x.A[0].IsGenericType &&
+                            x.A[0].GetGenericTypeDefinition() == typeof(Func<,>))
+                .Select(x => new { x.M, A = x.A[0].GetGenericArguments() })
+                .Where(x => x.A[0].IsGenericParameter &&
+                            x.A[1] == typeof(bool))
+                .Select(x => x.M)
+                .SingleOrDefault();
+
+            var result = whereMethod?.MakeGenericMethod(elementType).Invoke(null, new object[] { enumerable.AsQueryable(), lambda });
+
+            return result;
+        }
+
+
+        private static object ParsePropertyValue(string value, Type valueType)
+        {
+            if ((valueType == typeof(int) || valueType == typeof(int?)) && int.TryParse(value, out var intValue))
+            {
+                return intValue;
+            }
+
+            if (valueType == typeof(double) && double.TryParse(value, out var doubleValue))
+            {
+                return doubleValue;
+            }
+
+            if (valueType == typeof(decimal) && decimal.TryParse(value, out var decimalValue))
+            {
+                return decimalValue;
+            }
+
+            if (valueType == typeof(TimeSpan) && TimeSpan.TryParse(value, out var timespan))
+            {
+                return timespan;
+            }
+
+            if (valueType == typeof(DateTime) && DateTime.TryParse(value, out var dateTime))
+            {
+                return dateTime;
+            }
+
+            if (valueType == typeof(char) && char.TryParse(value, out var charValue))
+            {
+                return charValue;
+            }
+
+            if (valueType == typeof(bool) && bool.TryParse(value, out var boolValue))
+            {
+                return boolValue;
+            }
+
+            return value;
+        }
+
+        private static Type GetEnumerableElementType(Type type)
+        {
+            return type.GetInterfaces()
+                .Where(x => x.IsGenericType && x.GetGenericTypeDefinition() == typeof(IEnumerable<>))
+                .Select(x => x.GetGenericArguments()[0])
+                .FirstOrDefault();
+        }
+    }
+}

src/VirtoCommerce.NotificationsModule.Web/Module.cs

@@ -119,6 +119,7 @@ public void Initialize(IServiceCollection serviceCollection)
             {
                 builder.AddCustomLiquidFilterType(typeof(TranslationFilter));
                 builder.AddCustomLiquidFilterType(typeof(UrlFilters));
+                builder.AddCustomLiquidFilterType(typeof(ArrayFilter));
                 builder.SetRendererLoopLimit(Configuration["Notifications:LiquidRenderOptions:LoopLimit"].TryParse(ModuleConstants.DefaultLiquidRendererLoopLimit));
             });
         }

tests/VirtoCommerce.NotificationsModule.Tests/UnitTests/LiquidTemplateRendererUnitTests.cs

@@ -38,7 +38,7 @@ public LiquidTemplateRendererUnitTests()
             _notificationLayoutSearchService.Setup(x => x.SearchAsync(It.IsAny<NotificationLayoutSearchCriteria>(), It.IsAny<bool>())).ReturnsAsync(notificationLayoutSearchResult);
 
             Func<ITemplateLoader> factory = () => new LayoutTemplateLoader(_notificationLayoutServiceMock.Object);
-            _liquidTemplateRenderer = new LiquidTemplateRenderer(Options.Create(new LiquidRenderOptions() { CustomFilterTypes = new HashSet<Type> { typeof(UrlFilters), typeof(TranslationFilter) } }), factory, _notificationLayoutSearchService.Object);
+            _liquidTemplateRenderer = new LiquidTemplateRenderer(Options.Create(new LiquidRenderOptions() { CustomFilterTypes = new HashSet<Type> { typeof(UrlFilters), typeof(TranslationFilter), typeof(ArrayFilter) } }), factory, _notificationLayoutSearchService.Object);
 
             //TODO
             if (!AbstractTypeFactory<NotificationScriptObject>.AllTypeInfos.SelectMany(x => x.AllSubclasses).Contains(typeof(NotificationScriptObject)))
@@ -152,6 +152,43 @@ public async Task RenderAsync_ContextHasLayoutId_LayoutRendered()
             Assert.Equal("header test_content footer", result);
         }
 
+        [Theory]
+        [InlineData("Group", "==", "Group2", "Item2", "Item4")]
+        [InlineData("Group", "!=", "Group22", "Item1", "Item4")]
+        [InlineData("Value", ">", "2", "Item3", "Item5")]
+        [InlineData("Value", ">=", "2", "Item2", "Item5")]
+        [InlineData("Value", "<", "4", "Item1", "Item3")]
+        [InlineData("Value", "<=", "4", "Item1", "Item4")]
+        [InlineData("Group", "contains", "2", "Item2", "Item5")]
+        public async Task RenderAsync_FilterArray(string propertyName, string operationName, string propertyValue, string expectedFirstName, string expectedLastName)
+        {
+            var filter = $"'{propertyName}' '{operationName}' '{propertyValue}'";
+
+            var context = new NotificationRenderContext
+            {
+                Template = "{{ filtered = items | where: " + filter + " }}" +
+                           "{{ first_item = filtered | array.first }}" +
+                           "{{ last_item = filtered | array.last }}" +
+                           "First: {{ first_item.name }}, Last: {{ last_item.name }}",
+                Model = new
+                {
+                    Items = new[]
+                    {
+                        new { Group = "Group1", Name = "Item1", Value = 1 },
+                        new { Group = "Group2", Name = "Item2", Value = 2 },
+                        new { Group = "Group2", Name = "Item3", Value = 3 },
+                        new { Group = "Group2", Name = "Item4", Value = 4 },
+                        new { Group = "Group22", Name = "Item5", Value = 5 },
+                    }
+                },
+            };
+
+            var expectedResult = $"First: {expectedFirstName}, Last: {expectedLastName}";
+
+            var result = await _liquidTemplateRenderer.RenderAsync(context);
+            Assert.Equal(expectedResult, result);
+        }
+
         public static IEnumerable<object[]> TranslateData
         {
             get