#102: Ability to create an index

LATEST_CHANGE.md

@@ -1,4 +1,5 @@
 ## Features
+* **Indexes"**: Ability to create indexes.
 * **Null values"**: New `SetNullValueHandling` method for `CouchOptionsBuilder` to set how to handle null values.
 
 ## Bug Fixes

src/.editorconfig

@@ -147,3 +147,6 @@ csharp_preserve_single_line_statements = true
 
 # CA1303: Do not pass literals as localized parameters
 dotnet_diagnostic.CA1303.severity = silent
+
+# CA1308: Normalize strings to uppercase
+dotnet_diagnostic.CA1308.severity = suggestion

src/CouchDB.Driver/ChangesFeed/ChangesFeedFilterExtensions.cs

@@ -1,14 +1,12 @@
 using System;
 using System.IO;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Net.Http;
 using System.Threading;
 using System.Threading.Tasks;
 using CouchDB.Driver.ChangesFeed.Filters;
 using CouchDB.Driver.ChangesFeed.Responses;
 using CouchDB.Driver.Extensions;
-using CouchDB.Driver.Options;
 using CouchDB.Driver.Query;
 using CouchDB.Driver.Types;
 using Flurl.Http;
@@ -17,7 +15,7 @@ namespace CouchDB.Driver.ChangesFeed
 {
     internal static class ChangesFeedFilterExtensions
     {
-        public static async Task<ChangesFeedResponse<TSource>> QueryWithFilterAsync<TSource>(this IFlurlRequest request, CouchOptions options, ChangesFeedFilter filter,
+        public static async Task<ChangesFeedResponse<TSource>> QueryWithFilterAsync<TSource>(this IFlurlRequest request, IAsyncQueryProvider queryProvider, ChangesFeedFilter filter,
             CancellationToken cancellationToken)
             where TSource : CouchDocument
         {
@@ -32,12 +30,9 @@ public static async Task<ChangesFeedResponse<TSource>> QueryWithFilterAsync<TSou
 
             if (filter is SelectorChangesFeedFilter<TSource> selectorFilter)
             {
-                MethodCallExpression whereExpression = Expression.Call(typeof(Queryable), nameof(Queryable.Where),
-                    new[] { typeof(TSource) }, Expression.Constant(Array.Empty<TSource>().AsQueryable()), selectorFilter.Value);
+                MethodCallExpression whereExpression = selectorFilter.Value.WrapInWhereExpression();
+                var jsonSelector = queryProvider.ToString(whereExpression);
 
-                var optimizer = new QueryOptimizer();
-                Expression optimizedQuery = optimizer.Optimize(whereExpression);
-                var jsonSelector = new QueryTranslator(options).Translate(optimizedQuery);
                 return await request
                     .WithHeader("Content-Type", "application/json")
                     .SetQueryParam("filter", "_selector")
@@ -65,7 +60,7 @@ public static async Task<ChangesFeedResponse<TSource>> QueryWithFilterAsync<TSou
             throw new InvalidOperationException($"Filter of type {filter.GetType().Name} not supported.");
         }
 
-        public static async Task<Stream> QueryContinuousWithFilterAsync<TSource>(this IFlurlRequest request, CouchOptions options, ChangesFeedFilter filter, CancellationToken cancellationToken)
+        public static async Task<Stream> QueryContinuousWithFilterAsync<TSource>(this IFlurlRequest request, IAsyncQueryProvider queryProvider, ChangesFeedFilter filter, CancellationToken cancellationToken)
             where TSource: CouchDocument
         {
             if (filter is DocumentIdsChangesFeedFilter documentIdsFilter)
@@ -78,12 +73,9 @@ public static async Task<Stream> QueryContinuousWithFilterAsync<TSource>(this IF
 
             if (filter is SelectorChangesFeedFilter<TSource> selectorFilter)
             {
-                MethodCallExpression whereExpression = Expression.Call(typeof(Queryable), nameof(Queryable.Where),
-                    new[] { typeof(TSource) }, Expression.Constant(Array.Empty<TSource>().AsQueryable()), selectorFilter.Value);
+                MethodCallExpression whereExpression = selectorFilter.Value.WrapInWhereExpression();
+                var jsonSelector = queryProvider.ToString(whereExpression);
 
-                var optimizer = new QueryOptimizer();
-                Expression optimizedQuery = optimizer.Optimize(whereExpression);
-                var jsonSelector = new QueryTranslator(options).Translate(optimizedQuery);
                 return await request
                     .WithHeader("Content-Type", "application/json")
                     .SetQueryParam("filter", "_selector")

src/CouchDB.Driver/CouchDatabase.cs

@@ -8,19 +8,22 @@
 using System;
 using System.Collections;
 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.Runtime.CompilerServices;
+using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 using CouchDB.Driver.ChangesFeed;
 using CouchDB.Driver.ChangesFeed.Responses;
+using CouchDB.Driver.Indexes;
 using CouchDB.Driver.Local;
 using CouchDB.Driver.Options;
 using CouchDB.Driver.Query;
+using Flurl.Util;
 using Newtonsoft.Json;
 
 namespace CouchDB.Driver
@@ -374,7 +377,7 @@ public async Task<ChangesFeedResponse<TSource>> GetChangesAsync(ChangesFeedOptio
             return filter == null
                 ? await request.GetJsonAsync<ChangesFeedResponse<TSource>>(cancellationToken)
                     .ConfigureAwait(false)
-                : await request.QueryWithFilterAsync<TSource>(_options, filter, cancellationToken)
+                : await request.QueryWithFilterAsync<TSource>(_queryProvider, filter, cancellationToken)
                     .ConfigureAwait(false);
         }
 
@@ -396,7 +399,7 @@ public async IAsyncEnumerable<ChangesFeedResponseResult<TSource>> GetContinuousC
             await using Stream stream = filter == null
                 ? await request.GetStreamAsync(cancellationToken, HttpCompletionOption.ResponseHeadersRead)
                     .ConfigureAwait(false)
-                : await request.QueryContinuousWithFilterAsync<TSource>(_options, filter, cancellationToken)
+                : await request.QueryContinuousWithFilterAsync<TSource>(_queryProvider, filter, cancellationToken)
                     .ConfigureAwait(false);
 
             await foreach (var line in stream.ReadLinesAsync(cancellationToken))
@@ -413,6 +416,45 @@ public async IAsyncEnumerable<ChangesFeedResponseResult<TSource>> GetContinuousC
 
         #endregion
 
+        #region Index
+
+        public async Task CreateIndexAsync(string name, Action<IIndexBuilder<TSource>> indexBuilderAction, IndexOptions? options = null)
+        {
+            Check.NotNull(name, nameof(name));
+            Check.NotNull(indexBuilderAction, nameof(indexBuilderAction));
+
+            var builder = new IndexBuilder<TSource>(_options, _queryProvider);
+            indexBuilderAction(builder);
+
+            var indexJson = builder.ToString();
+
+            var sb = new StringBuilder();
+            sb.Append("{")
+                .Append($"\"index\":{indexJson},")
+                .Append($"\"name\":\"{name}\",")
+                .Append("\"type\":\"json\"");
+
+            if (options?.DesignDocument != null)
+            {
+                sb.Append($",\"ddoc\":\"{options.DesignDocument}\"");
+            }
+            if (options?.Partitioned != null)
+            {
+                sb.Append($",\"partitioned\":{options.Partitioned.ToString().ToLowerInvariant()}");
+            }
+
+            sb.Append("}");
+
+            var request = sb.ToString();
+
+            await NewRequest().AppendPathSegment("_index")
+                .PostStringAsync(request)
+                .SendRequestAsync()
+                .ConfigureAwait(false);
+        }
+
+        #endregion
+
         #region Utils
 
         /// <inheritdoc />
@@ -495,4 +537,4 @@ internal CouchQueryable<TSource> AsQueryable()
 
         #endregion
     }
-}
+}

src/CouchDB.Driver/Extensions/ExpressionExtensions.cs

@@ -1,11 +1,43 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Linq.Expressions;
+using CouchDB.Driver.Options;
 
 namespace CouchDB.Driver.Extensions
 {
     internal static class ExpressionExtensions
     {
+        public static MemberExpression ToMemberExpression(this Expression selector)
+        {
+            if (!(selector is LambdaExpression l) || !(l.Body is MemberExpression m))
+            {
+                throw new ArgumentException("The given expression does not select a property.", nameof(selector));
+            }
+
+            return m;
+        }
+
+        public static string GetPropertyName(this MemberExpression m, CouchOptions options)
+        {
+            PropertyCaseType caseType = options.PropertiesCase;
+
+            var members = new List<string> { m.Member.GetCouchPropertyName(caseType) };
+
+            Expression currentExpression = m.Expression;
+
+            while (currentExpression is MemberExpression cm)
+            {
+                members.Add(cm.Member.GetCouchPropertyName(caseType));
+                currentExpression = cm.Expression;
+            }
+
+            members.Reverse();
+            var propName = string.Join(".", members.ToArray());
+
+            return propName;
+        }
+
         public static bool ContainsSelector(this Expression expression) =>
             expression is MethodCallExpression m && m.Arguments.Count == 2 && m.Arguments[1].IsSelectorExpression();
 
@@ -39,6 +71,13 @@ public static Expression WrapInLambda(this Expression body, IReadOnlyCollection<
             return Expression.Quote(lambdaExpression);
         }
 
+        public static MethodCallExpression WrapInWhereExpression<TSource>(this Expression<Func<TSource, bool>> selector)
+        {
+            MethodCallExpression whereExpression = Expression.Call(typeof(Queryable), nameof(Queryable.Where),
+                new[] { typeof(TSource) }, Expression.Constant(Array.Empty<TSource>().AsQueryable()), selector);
+            return whereExpression;
+        }
+
         private static Expression StripQuotes(this Expression e)
         {
             while (e.NodeType == ExpressionType.Quote)

src/CouchDB.Driver/Extensions/FlurlRequestExtensions.cs

@@ -45,7 +45,6 @@ public static Task<Stream> PostStringStreamAsync(
             return request.SendAsync(HttpMethod.Post, capturedStringContent, cancellationToken, completionOption).ReceiveStream();
         }
 
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("Globalization", "CA1308:Normalize strings to uppercase", Justification = "<Pending>")]
         public static IFlurlRequest ApplyQueryParametersOptions(this IFlurlRequest request, object options)
         {
             IEnumerable<(string Name, object? Value)> queryParameters = OptionsHelper.ToQueryParameters(options);

src/CouchDB.Driver/ICouchDatabase.cs

@@ -1,9 +1,11 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using CouchDB.Driver.ChangesFeed;
 using CouchDB.Driver.ChangesFeed.Responses;
+using CouchDB.Driver.Indexes;
 using CouchDB.Driver.Local;
 using CouchDB.Driver.Security;
 using CouchDB.Driver.Types;
@@ -124,7 +126,17 @@ IAsyncEnumerable<ChangesFeedResponseResult<TSource>> GetContinuousChangesAsync(
             CancellationToken cancellationToken);
 
         /// <summary>
-        ///  Asynchronously downloads a specific attachment.
+        /// Creates an index for the current database with the given configuration.
+        /// </summary>
+        /// <param name="name">The name of the index.</param>
+        /// <param name="indexBuilderAction">The action to configure the index builder.</param>
+        /// <param name="options">The index options.</param>
+        /// <returns>A task that represents the asynchronous operation.</returns>
+        Task CreateIndexAsync(string name, Action<IIndexBuilder<TSource>> indexBuilderAction,
+            IndexOptions? options = null);
+
+        /// <summary>
+        /// Asynchronously downloads a specific attachment.
         /// </summary>
         /// <param name="attachment">The attachment to download.</param>
         /// <param name="localFolderPath">Path of local folder where file is to be downloaded.</param>

src/CouchDB.Driver/Indexes/IIndexBuilder.cs

@@ -0,0 +1,35 @@
+using System;
+using System.Linq.Expressions;
+using CouchDB.Driver.Types;
+
+namespace CouchDB.Driver.Indexes
+{
+    public interface IIndexBuilder<TSource>
+        where TSource : CouchDocument
+    {
+        IMultiFieldIndexBuilder<TSource> IndexBy<TSelector>(Expression<Func<TSource, TSelector>> selector);
+    }
+
+    public interface IMultiFieldIndexBuilder<TSource> : IIndexBuilder<TSource>
+        where TSource : CouchDocument
+    {
+        IMultiFieldIndexBuilder<TSource> AlsoBy<TSelector>(Expression<Func<TSource, TSelector>> selector);
+        IMultiFieldIndexBuilder<TSource> Where(Expression<Func<TSource, bool>> selector);
+        IOrderedIndexBuilder<TSource> OrderBy<TSelector>(Expression<Func<TSource, TSelector>> selector);
+        IOrderedDescendingIndexBuilder<TSource> OrderByDescending<TSelector>(Expression<Func<TSource, TSelector>> selector);
+        IMultiFieldIndexBuilder<TSource> Take(int take);
+        IMultiFieldIndexBuilder<TSource> Skip(int skip);
+    }
+
+    public interface IOrderedIndexBuilder<TSource> : IMultiFieldIndexBuilder<TSource>
+        where TSource : CouchDocument
+    {
+        IOrderedIndexBuilder<TSource> ThenBy<TSelector>(Expression<Func<TSource, TSelector>> selector);
+    }
+
+    public interface IOrderedDescendingIndexBuilder<TSource> : IMultiFieldIndexBuilder<TSource>
+        where TSource : CouchDocument
+    {
+        IOrderedDescendingIndexBuilder<TSource> ThenByDescending<TSelector>(Expression<Func<TSource, TSelector>> selector);
+    }
+}