Feat/#482

docs/usage/resources/resource-definitions.md

@@ -113,9 +113,9 @@ public class ItemResource : ResourceDefinition<Item>
     // handles queries like: ?filter[was-active-on]=2018-10-15T01:25:52Z
     public override QueryFilters GetQueryFilters()
         => new QueryFilters {            
-            { "was-active-on", (items, value) => DateTime.TryParse(value, out dateValue)
+            { "was-active-on", (items, filter) => DateTime.TryParse(filter.Value, out dateValue)
                 ? items.Where(i => i.Expired == null || dateValue < i.Expired)
-                : throw new JsonApiException(400, $"'{value}' is not a valid date.")
+                : throw new JsonApiException(400, $"'{filter.Value}' is not a valid date.")
             }
         };
 }
@@ -128,4 +128,4 @@ Prior to the introduction of auto-discovery, you needed to register the
 
 ```c#
 services.AddScoped<ResourceDefinition<Item>, ItemResource>();
-```
+```

src/Examples/JsonApiDotNetCoreExample/Resources/UserResource.cs

@@ -1,12 +1,33 @@
 using System.Collections.Generic;
+using System.Linq;
 using JsonApiDotNetCore.Models;
 using JsonApiDotNetCoreExample.Models;
+using JsonApiDotNetCore.Internal.Query;
 
 namespace JsonApiDotNetCoreExample.Resources
 {
     public class UserResource : ResourceDefinition<User>
     {
         protected override List<AttrAttribute> OutputAttrs()
             => Remove(user => user.Password);
+
+        public override QueryFilters GetQueryFilters()
+        {
+          return new QueryFilters
+          {
+            { "first-character", (users, queryFilter) => FirstCharacterFilter(users, queryFilter) }
+          };
+        }
+
+        private IQueryable<User> FirstCharacterFilter(IQueryable<User> users, FilterQuery filterQuery)
+        {
+          switch(filterQuery.Operation)
+          {
+            case "lt":
+              return users.Where(u => u.Username[0] < filterQuery.Value[0]);
+            default:
+              return users.Where(u => u.Username[0] == filterQuery.Value[0]);
+          }
+        }
     }
 }

src/JsonApiDotNetCore/Data/DefaultEntityRepository.cs

@@ -108,7 +108,7 @@ public virtual IQueryable<TEntity> Filter(IQueryable<TEntity> entities, FilterQu
                 var defaultQueryFilters = _resourceDefinition.GetQueryFilters();
                 if (defaultQueryFilters != null && defaultQueryFilters.TryGetValue(filterQuery.Attribute, out var defaultQueryFilter) == true)
                 {
-                    return defaultQueryFilter(entities, filterQuery.Value);
+                    return defaultQueryFilter(entities, filterQuery);
                 }
             }
 

src/JsonApiDotNetCore/Models/ResourceDefinition.cs

@@ -162,7 +162,7 @@ private List<AttrAttribute> GetOutputAttrs()
         /// method signature.
         /// See <see cref="GetQueryFilters" /> for usage details.
         /// </summary>
-        public class QueryFilters : Dictionary<string, Func<IQueryable<T>, string, IQueryable<T>>> { }
+        public class QueryFilters : Dictionary<string, Func<IQueryable<T>, FilterQuery, IQueryable<T>>> { }
 
         /// <summary>
         /// Define a the default sort order if no sort key is provided.

test/JsonApiDotNetCoreExampleTests/Acceptance/ResourceDefinitions/QueryFiltersTests.cs

@@ -0,0 +1,85 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Net;
+using System.Net.Http;
+using System.Net.Http.Headers;
+using System.Threading.Tasks;
+using Bogus;
+using JsonApiDotNetCore.Models;
+using JsonApiDotNetCore.Serialization;
+using JsonApiDotNetCoreExample.Data;
+using JsonApiDotNetCoreExample.Models;
+using Microsoft.EntityFrameworkCore;
+using Newtonsoft.Json;
+using Xunit;
+
+namespace JsonApiDotNetCoreExampleTests.Acceptance
+{
+    [Collection("WebHostCollection")]
+    public class QueryFiltersTests
+    {
+      private TestFixture<TestStartup> _fixture;
+      private AppDbContext _context;
+      private Faker<User> _userFaker;
+
+      public QueryFiltersTests(TestFixture<TestStartup> fixture)
+      {
+        _fixture = fixture;
+        _context = fixture.GetService<AppDbContext>();
+        _userFaker = new Faker<User>()
+          .RuleFor(u => u.Username, f => f.Internet.UserName())
+          .RuleFor(u => u.Password, f => f.Internet.Password());
+      }
+
+      [Fact]
+      public async Task FiltersWithCustomQueryFiltersEquals()
+      {
+        // Arrange
+        var user = _userFaker.Generate();
+        var firstUsernameCharacter = user.Username[0];
+        _context.Users.Add(user);
+        _context.SaveChanges();
+
+        var httpMethod = new HttpMethod("GET");
+        var route = $"/api/v1/users?filter[first-character]=eq:{firstUsernameCharacter}";
+        var request = new HttpRequestMessage(httpMethod, route);
+
+        // Act
+        var response = await _fixture.Client.SendAsync(request);
+
+        // Assert
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+        var body = await response.Content.ReadAsStringAsync();
+        var deserializedBody = _fixture.GetService<IJsonApiDeSerializer>().DeserializeList<User>(body);
+        var usersWithFirstCharacter = _context.Users.Where(u => u.Username[0] == firstUsernameCharacter);
+        Assert.True(deserializedBody.All(u => u.Username[0] == firstUsernameCharacter));
+      }
+
+      [Fact]
+      public async Task FiltersWithCustomQueryFiltersLessThan()
+      {
+        // Arrange
+        var aUser = _userFaker.Generate();
+        aUser.Username = "alfred";
+        var zUser = _userFaker.Generate();
+        zUser.Username = "zac";
+        _context.Users.AddRange(aUser, zUser);
+        _context.SaveChanges();
+
+        var median = 'h';
+
+        var httpMethod = new HttpMethod("GET");
+        var route = $"/api/v1/users?filter[first-character]=lt:{median}";
+        var request = new HttpRequestMessage(httpMethod, route);
+
+        // Act
+        var response = await _fixture.Client.SendAsync(request);
+
+        // Assert
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+        var body = await response.Content.ReadAsStringAsync();
+        var deserializedBody = _fixture.GetService<IJsonApiDeSerializer>().DeserializeList<User>(body);
+        Assert.True(deserializedBody.All(u => u.Username[0] < median));
+      }
+    }
+}