Moved over SendFileAsync as virtual method on HttpResponse

Author: khellang

src/Microsoft.AspNetCore.Http.Abstractions/HttpResponse.cs

@@ -3,7 +3,9 @@
 
 using System;
 using System.IO;
+using System.Threading;
 using System.Threading.Tasks;
+using Microsoft.AspNetCore.Http.Features;
 
 namespace Microsoft.AspNetCore.Http
 {
@@ -103,5 +105,80 @@ public abstract class HttpResponse
         /// <param name="location">The URL to redirect the client to.</param>
         /// <param name="permanent"><c>True</c> if the redirect is permanent (301), otherwise <c>false</c> (302).</param>
         public abstract void Redirect(string location, bool permanent);
+
+        /// <summary>
+        /// Sends the given file using the SendFile extension.
+        /// </summary>
+        /// <param name="fileName">The full path to the file.</param>
+        /// <returns></returns>
+        public virtual Task SendFileAsync(string fileName)
+        {
+            if (fileName == null)
+            {
+                throw new ArgumentNullException(nameof(fileName));
+            }
+
+            return SendFileAsync(fileName, 0, null, CancellationToken.None);
+        }
+
+        /// <summary>
+        /// Sends the given file using the SendFile extension.
+        /// </summary>
+        /// <param name="fileName">The full path to the file.</param>
+        /// <param name="offset">The offset in the file.</param>
+        /// <param name="count">The number of types to send, or null to send the remainder of the file.</param>
+        /// <param name="cancellationToken"></param>
+        /// <returns></returns>
+        public virtual Task SendFileAsync(string fileName, long offset, long? count, CancellationToken cancellationToken = default(CancellationToken))
+        {
+            if (fileName == null)
+            {
+                throw new ArgumentNullException(nameof(fileName));
+            }
+
+            var sendFile = HttpContext.Features.Get<IHttpSendFileFeature>();
+
+            if (sendFile == null)
+            {
+                return SendFileAsync(Body, fileName, offset, count, cancellationToken);
+            }
+
+            return sendFile.SendFileAsync(fileName, offset, count, cancellationToken);
+        }
+
+        // Not safe for overlapped writes.
+        private static async Task SendFileAsync(Stream outputStream, string fileName, long offset, long? length, CancellationToken cancellationToken)
+        {
+            cancellationToken.ThrowIfCancellationRequested();
+
+            var fileInfo = new FileInfo(fileName);
+            if (offset < 0 || offset > fileInfo.Length)
+            {
+                throw new ArgumentOutOfRangeException(nameof(offset), offset, string.Empty);
+            }
+
+            if (length.HasValue &&
+                (length.Value < 0 || length.Value > fileInfo.Length - offset))
+            {
+                throw new ArgumentOutOfRangeException(nameof(length), length, string.Empty);
+            }
+
+            int bufferSize = 1024 * 16;
+
+            var fileStream = new FileStream(
+                fileName,
+                FileMode.Open,
+                FileAccess.Read,
+                FileShare.ReadWrite,
+                bufferSize: bufferSize,
+                options: FileOptions.Asynchronous | FileOptions.SequentialScan);
+
+            using (fileStream)
+            {
+                fileStream.Seek(offset, SeekOrigin.Begin);
+
+                await StreamCopyOperation.CopyToAsync(fileStream, outputStream, length, cancellationToken);
+            }
+        }
     }
 }

src/Microsoft.AspNetCore.Http.Extensions/StreamCopyOperation.cs renamed to src/Microsoft.AspNetCore.Http.Abstractions/StreamCopyOperation.cs

@@ -8,7 +8,7 @@
 using System.Threading;
 using System.Threading.Tasks;
 
-namespace Microsoft.AspNetCore.Http.Extensions
+namespace Microsoft.AspNetCore.Http
 {
     // FYI: In most cases the source will be a FileStream and the destination will be to the network.
     public static class StreamCopyOperation

src/Microsoft.AspNetCore.Http.Abstractions/project.json

@@ -15,7 +15,8 @@
       "type": "build",
       "version": "1.0.0-*"
     },
-    "System.Text.Encodings.Web": "4.0.0-*"
+    "System.Text.Encodings.Web": "4.0.0-*",
+    "System.Buffers": "4.0.0-*"
   },
   "frameworks": {
     "net451": {
@@ -32,7 +33,8 @@
         "System.Net.WebSockets": "4.0.0-*",
         "System.Reflection.TypeExtensions": "4.1.0-*",
         "System.Runtime.InteropServices": "4.0.21-*",
-        "System.Security.Cryptography.X509Certificates": "4.0.0-*"
+        "System.Security.Cryptography.X509Certificates": "4.0.0-*",
+        "System.IO.FileSystem": "4.0.1-*"
       }
     }
   }

src/Microsoft.AspNetCore.Http.Extensions/SendFileResponseExtensions.cs

@@ -11,15 +11,10 @@
   },
   "dependencies": {
     "Microsoft.AspNetCore.Http.Abstractions": "1.0.0-*",
-    "Microsoft.Net.Http.Headers": "1.0.0-*",
-    "System.Buffers": "4.0.0-*"
+    "Microsoft.Net.Http.Headers": "1.0.0-*"
   },
   "frameworks": {
     "net451": {},
-    "dotnet5.4": {
-      "dependencies": {
-        "System.IO.FileSystem": "4.0.1-*"
-      }
-    }
+    "dotnet5.4": { }
   }
 }