Add support for filtering by enum property types

"Fix" this support in CosmosDB table client, which does not support this type of query :).

Fixes #35

src/TableStorage/DocumentSerializer.cs

@@ -24,6 +24,11 @@ partial class DocumentSerializer : IStringDocumentSerializer
             AllowTrailingCommas = true,
             DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingDefault,
             WriteIndented = true,
+            Converters =
+            {
+                // Enums should persist/parse with their string values instead
+                new JsonStringEnumConverter(allowIntegerValues: false)
+            }
         };
 
         /// <summary>

src/TableStorage/TableRepositoryQuery.cs

@@ -46,10 +46,18 @@ public async IAsyncEnumerator<T> GetAsyncEnumerator(CancellationToken cancellati
             var query = (DataServiceQuery)new DataServiceContext(account.TableStorageUri.PrimaryUri).CreateQuery<T>(tableName)
                 .Provider.CreateQuery(expression);
 
+            // OData will translate the enum value in a filter to TYPENAME.'ENUMVALUE'.
+            // The type name can contain the + sign if it's a nested type, too. So we
+            // need to remove the type name plus the dot and just leave the string 
+            // value as part of the filter string.
+            var rawqs = Regex.Replace(
+                query.RequestUri.GetComponents(UriComponents.Query, UriFormat.Unescaped),
+                "(\\W)[\\w\\+\\.]+('\\w+')", "$1$2");
+
             // We need to count & break manually because $top is interpreted as the max records per page 
             // if the set matches more items. This is clearly unintuitive and *not* what one typically 
             // wants when using LINQ queries! See Note on https://docs.microsoft.com/en-us/rest/api/storageservices/querying-tables-and-entities#supported-query-options
-            var qs = HttpUtility.ParseQueryString(query.RequestUri.GetComponents(UriComponents.Query, UriFormat.Unescaped));
+            var qs = HttpUtility.ParseQueryString(rawqs);
             if (!long.TryParse(qs["$top"], out var top))
                 top = -1;
 

src/Tests/QueryTests.cs

@@ -1,18 +1,9 @@
 using System;
 using System.Collections.Generic;
-using System.Globalization;
 using System.IO;
 using System.Linq;
-using System.Linq.Expressions;
-using System.Net;
-using System.Net.Http;
-using System.Reflection;
-using System.Runtime.InteropServices;
-using System.Text.Json;
 using System.Threading.Tasks;
 using Microsoft.Azure.Cosmos.Table;
-using Microsoft.OData.Client;
-using Microsoft.OData.UriParser;
 using Xunit;
 
 namespace Devlooped
@@ -27,7 +18,7 @@ public async Task CanTake()
             await LoadBooksAsync(repo);
 
             var query = from book in repo.CreateQuery()
-                        where book.Format == "Hardback" && book.IsPublished
+                        where book.Format == BookFormat.Hardback && book.IsPublished
                         select new { book.ISBN, book.Title };
 
             var result = await query.Take(2).AsAsyncEnumerable().ToListAsync();
@@ -58,7 +49,7 @@ public async Task CanProject()
             var hasResults = false;
 
             await foreach (var info in from book in repo.CreateQuery()
-                                       where book.Author == "Rick Riordan" && book.Format == "Hardback" && book.IsPublished
+                                       where book.Author == "Rick Riordan" && book.Format == BookFormat.Hardback && book.IsPublished
                                        select new { book.ISBN, book.Title })
             {
                 hasResults = true;
@@ -83,7 +74,7 @@ public async Task CanProjectPartition()
             var hasResults = false;
 
             await foreach (var info in from book in repo.CreateQuery()
-                                       where book.Format == "Hardback" && book.IsPublished
+                                       where book.Format == BookFormat.Hardback && book.IsPublished
                                        select new { book.ISBN, book.Title })
             {
                 hasResults = true;
@@ -94,42 +85,41 @@ public async Task CanProjectPartition()
             Assert.True(hasResults);
         }
 
+        [Fact]
+        public async Task EnumFailsInTableClient()
+        {
+            var account = CloudStorageAccount.DevelopmentStorageAccount;
+            var table = account.CreateCloudTableClient().GetTableReference(nameof(EnumFailsInTableClient));
+
+            await table.CreateIfNotExistsAsync();
+
+            Assert.Throws<StorageException>(() =>
+                (from book in table.CreateQuery<BookEntity>()
+                 where book.Format == BookFormat.Hardback && book.IsPublished
+                 select new { book.Title })
+                .ToList());
+        }
+
+
         async Task LoadBooksAsync(ITableRepository<Book> books)
         {
             foreach (var book in File.ReadAllLines("Books.csv").Skip(1)
                 .Select(line => line.Split(','))
-                .Select(values => new Book(values[1], values[2], values[3], values[4], int.Parse(values[5]), bool.Parse(values[6]))))
+                .Select(values => new Book(values[1], values[2], values[3], Enum.Parse<BookFormat>(values[4]), int.Parse(values[5]), bool.Parse(values[6]))))
             {
                 await books.PutAsync(book);
             }
         }
 
-        public record Book(string ISBN, string Title, string Author, string Format, int? Pages = null, bool IsPublished = true);
+        public enum BookFormat { Paperback, Hardback }
 
-        public class RequestStatusEntity : TableEntity
-        {
-            public RequestStatusEntity()
-            {
-            }
-
-            public RequestStatusEntity(string ID) : base(nameof(RequestStatus), ID)
-            {
-            }
-
-            public string? ID
-            {
-                get => RowKey;
-                set => RowKey = value;
-            }
-
-            public int Status { get; set; }
-            public string? Reason { get; set; }
-        }
+        public record Book(string ISBN, string Title, string Author, BookFormat Format, int? Pages = null, bool IsPublished = true);
 
-        public record RequestStatus(string ID)
+        public class BookEntity : TableEntity
         {
-            public int Status { get; set; }
-            public string? Reason { get; set; }
+            public bool IsPublished { get; set; }
+            public string? Title { get; set; }
+            public BookFormat Format { get; set; }
         }
     }
 }