Made downloads stream the file while decrypting them.

Teknik/Areas/Upload/Controllers/UploadController.cs

@@ -176,8 +176,7 @@ namespace Teknik.Areas.Upload.Controllers
                             if (System.IO.File.Exists(filePath))
                             {
                                 // Read in the file
-                                using (FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Read))
+                                FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Read);
-                                {
                                 // We accept ranges
                                 Response.AddHeader("Accept-Ranges", "0-" + upload.ContentLength);
 
@@ -233,11 +232,6 @@ namespace Teknik.Areas.Upload.Controllers
 
                                     length = endByte - startByte + 1; // Calculate new content length 
 
-                                        // grab the portion of the data we want
-                                        byte[] dataRange = new byte[length];
-                                        //Array.Copy(data, startByte, dataRange, 0, length);
-                                        //data = dataRange;
-
                                     // Ranges are response of 206
                                     Response.StatusCode = 206;
                                 }
@@ -258,7 +252,7 @@ namespace Teknik.Areas.Upload.Controllers
                                     Inline = true
                                 };
 
-                                    Response.AppendHeader("Content-Disposition", cd.ToString());
+                                Response.AddHeader("Content-Disposition", cd.ToString());
 
                                 string contentType = upload.ContentType;
                                 // We need to prevent html (make cleaner later)
@@ -267,10 +261,8 @@ namespace Teknik.Areas.Upload.Controllers
                                     contentType = "text/plain";
                                 }
 
-                                    // Reset file stream to starting position
+                                // Reset file stream to starting position (or start of range)
-                                    fs.Seek(0, SeekOrigin.Begin);
+                                fs.Seek(startByte, SeekOrigin.Begin);
-
-                                    Response.BufferOutput = true;
 
                                 // If the IV is set, and Key is set, then decrypt it before sending
                                 if (!string.IsNullOrEmpty(upload.Key) && !string.IsNullOrEmpty(upload.IV))
@@ -278,26 +270,50 @@ namespace Teknik.Areas.Upload.Controllers
                                     byte[] keyBytes = Encoding.UTF8.GetBytes(upload.Key);
                                     byte[] ivBytes = Encoding.UTF8.GetBytes(upload.IV);
 
-                                        IBufferedCipher cipher = AES.CreateCipher(false, keyBytes, ivBytes, "CTR", "NoPadding");
+                                    return new FileDecryptResult(upload.Url, contentType, (response) => this.GenerateExportFile(response, fs, (int)length, keyBytes, ivBytes, "CTR", "NoPadding", 4 * 1024), false);
+                                }
+                                else
+                                {
+                                    // Don't buffer the response
+                                    Response.Buffer = false;
+                                    // Otherwise just send it
+                                    return File(fs, contentType);
+                                }
+                            }
+                        }
+                    }
+                }
+                return Redirect(Url.SubRouteUrl("error", "Error.Http404"));
+            }
+            return Redirect(Url.SubRouteUrl("error", "Error.Http403"));
+        }
 
-                                        int chunkSize = 1024;
+        public void GenerateExportFile(HttpResponseBase response, System.IO.Stream fileStream, int length, byte[] key, byte[] iv, string mode, string padding, int chunkSize)
+        {
+            response.Flush();
+            IBufferedCipher cipher = AES.CreateCipher(false, key, iv, mode, padding);
 
-                                        // Make sure the input stream is at the beginning
+            int curByte = 0;
-                                        fs.Seek(0, SeekOrigin.Begin);
             int processedBytes = 0;
             byte[] buffer = new byte[chunkSize];
             do
             {
-                                            processedBytes = AES.ProcessCipherBlock(cipher, fs, chunkSize, buffer, 0);
+                if (curByte + chunkSize > length)
+                {
+                    chunkSize = length - curByte;
+                }
+                processedBytes = AES.ProcessCipherBlock(cipher, fileStream, chunkSize, buffer, 0);
                 if (processedBytes > 0)
                 {
-                                                Response.OutputStream.Write(buffer, 0, processedBytes);
+                    response.OutputStream.Write(buffer, 0, processedBytes);
+                    response.Flush();
 
                     // Clear the buffer
                     Array.Clear(buffer, 0, chunkSize);
                 }
+                curByte += processedBytes;
             }
-                                        while (processedBytes > 0);
+            while (processedBytes > 0 && curByte < length);
 
             // Clear the buffer
             Array.Clear(buffer, 0, chunkSize);
@@ -307,25 +323,12 @@ namespace Teknik.Areas.Upload.Controllers
             if (processedBytes > 0)
             {
                 // We have bytes, lets write them to the output
-                                            Response.OutputStream.Write(buffer, 0, processedBytes);
+                response.OutputStream.Write(buffer, 0, processedBytes);
+                response.Flush();
             }
-                                        HttpContext.ApplicationInstance.CompleteRequest();
 
-                                        return Content("");
+            // dispose of file stream
-                                    }
+            fileStream.Dispose();
-                                    else
-                                    {
-                                        // Otherwise just send it
-                                        return File(fs, contentType);
-                                    }
-                                }
-                            }
-                        }
-                    }
-                }
-                return Redirect(Url.SubRouteUrl("error", "Error.Http404"));
-            }
-            return Redirect(Url.SubRouteUrl("error", "Error.Http403"));
         }
 
         [HttpPost]

Utilities/Utilities/FileDecryptResult.cs

@@ -1,8 +1,11 @@
-using System;
+using Org.BouncyCastle.Crypto;
+using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
+using System.Web;
 using System.Web.Mvc;
 
 namespace Teknik.Utilities
@@ -10,12 +13,9 @@ namespace Teknik.Utilities
     /// <summary>
     /// MVC action result that generates the file content using a delegate that writes the content directly to the output stream.
     /// </summary>
-    public class FileGeneratingResult : FileResult
+    public class FileDecryptResult : FileResult
     {
-        /// <summary>
+        private readonly Action<HttpResponseBase> responseDelegate;
-        /// The delegate that will generate the file content.
-        /// </summary>
-        private readonly Action<System.IO.Stream> content;
 
         private readonly bool bufferOutput;
 
@@ -26,15 +26,14 @@ namespace Teknik.Utilities
         /// <param name="contentType">Type of the content.</param>
         /// <param name="content">Delegate with Stream parameter. This is the stream to which content should be written.</param>
         /// <param name="bufferOutput">use output buffering. Set to false for large files to prevent OutOfMemoryException.</param>
-        public FileGeneratingResult(string fileName, string contentType, Action<System.IO.Stream> content, bool bufferOutput = true)
+        public FileDecryptResult(string fileName, string contentType, Action<HttpResponseBase> response, bool bufferOutput)
             : base(contentType)
         {
-            if (content == null)
+            if (response == null)
                 throw new ArgumentNullException("content");
 
-            this.content = content;
+            this.responseDelegate = response;
             this.bufferOutput = bufferOutput;
-            FileDownloadName = fileName;
         }
 
         /// <summary>
@@ -44,7 +43,7 @@ namespace Teknik.Utilities
         protected override void WriteFile(System.Web.HttpResponseBase response)
         {
             response.Buffer = bufferOutput;
-            content(response.OutputStream);
+            responseDelegate(response);
         }
     }
 }

Utilities/Utilities/Utilities.csproj

@@ -105,7 +105,7 @@
     </Reference>
   </ItemGroup>
   <ItemGroup>
-    <Compile Include="FileGeneratingResult.cs" />
+    <Compile Include="FileDecryptResult.cs" />
     <Compile Include="HttpWebResponseResult.cs" />
     <Compile Include="BundleExtensions.cs" />
     <Compile Include="ByteExtensions.cs" />