add queryable enumeration transform method

Chris Santero · Chris Santero · commit 4d0de76e6536 · 2015-07-08T23:39:47.000-04:00
The queryable transformer is a ghetto version of IEnumerable. It only
exists to let JSONAPI Core access an async version of methods like
ToArray. FirstOrDefault is another method we need.
diff --git a/JSONAPI.EntityFramework/ActionFilters/AsynchronousEnumerationTransformer.cs b/JSONAPI.EntityFramework/ActionFilters/AsynchronousEnumerationTransformer.cs
@@ -15,5 +15,10 @@ public async Task<T[]> Enumerate<T>(IQueryable<T> query, CancellationToken cance
         {
             return await query.ToArrayAsync(cancellationToken);
         }
+
+        public async Task<T> FirstOrDefault<T>(IQueryable<T> query, CancellationToken cancellationToken)
+        {
+            return await query.FirstOrDefaultAsync(cancellationToken);
+        }
     }
 }
diff --git a/JSONAPI/QueryableTransformers/IQueryableEnumerationTransformer.cs b/JSONAPI/QueryableTransformers/IQueryableEnumerationTransformer.cs
@@ -18,5 +18,14 @@ public interface IQueryableEnumerationTransformer
         /// <typeparam name="T">The queryable element type</typeparam>
         /// <returns>A task yielding the enumerated results of the query</returns>
         Task<T[]> Enumerate<T>(IQueryable<T> query, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Gets the first result for the specified query.
+        /// </summary>
+        /// <param name="query">The query to enumerate</param>
+        /// <param name="cancellationToken">The request's cancellation token. If this token is cancelled during enumeration, enumeration must halt.</param>
+        /// <typeparam name="T">The queryable element type</typeparam>
+        /// <returns>A task yielding the enumerated results of the query</returns>
+        Task<T> FirstOrDefault<T>(IQueryable<T> query, CancellationToken cancellationToken);
     }
 }
diff --git a/JSONAPI/QueryableTransformers/SynchronousEnumerationTransformer.cs b/JSONAPI/QueryableTransformers/SynchronousEnumerationTransformer.cs
@@ -13,5 +13,10 @@ public Task<T[]> Enumerate<T>(IQueryable<T> query, CancellationToken cancellatio
         {
             return Task.FromResult(query.ToArray());
         }
+
+        public Task<T> FirstOrDefault<T>(IQueryable<T> query, CancellationToken cancellationToken)
+        {
+            return Task.FromResult(query.FirstOrDefault());
+        }
     }
 }

Original file line number	Diff line number	Diff line change
`@@ -15,5 +15,10 @@ public async Task<T[]> Enumerate<T>(IQueryable<T> query, CancellationToken cance`
`15`	`15`	`{`
`16`	`16`	`return await query.ToArrayAsync(cancellationToken);`
`17`	`17`	`}`
	`18`	`+`
	`19`	`+ public async Task<T> FirstOrDefault<T>(IQueryable<T> query, CancellationToken cancellationToken)`
	`20`	`+ {`
	`21`	`+ return await query.FirstOrDefaultAsync(cancellationToken);`
	`22`	`+ }`
`18`	`23`	`}`
`19`	`24`	`}`
Original file line number	Diff line number	Diff line change
`@@ -13,5 +13,10 @@ public Task<T[]> Enumerate<T>(IQueryable<T> query, CancellationToken cancellatio`
`13`	`13`	`{`
`14`	`14`	`return Task.FromResult(query.ToArray());`
`15`	`15`	`}`
	`16`	`+`
	`17`	`+ public Task<T> FirstOrDefault<T>(IQueryable<T> query, CancellationToken cancellationToken)`
	`18`	`+ {`
	`19`	`+ return Task.FromResult(query.FirstOrDefault());`
	`20`	`+ }`
`16`	`21`	`}`
`17`	`22`	`}`