Decrypt messages asynchronously

Crypter-File-Transfer · May 6, 2024 · 940e91a · 940e91a
1 parent 163ff7a
commit 940e91a
Show file tree

Hide file tree

Showing 2 changed files with 18 additions and 6 deletions.
diff --git a/Crypter.Common.Client/Transfer/Handlers/DownloadFileHandler.cs b/Crypter.Common.Client/Transfer/Handlers/DownloadFileHandler.cs
@@ -85,7 +85,7 @@ public async Task<Either<DownloadTransferCiphertextError, DecryptionStream>> Dow
 
         return await response.MatchAsync<Either<DownloadTransferCiphertextError, DecryptionStream>>(
             error => error,
-            async response => await DecryptionStream.OpenAsync(response.Stream, response.StreamSize, symmetricKey, CryptoProvider.StreamEncryptionFactory),
+            async streamDownloadResponse => await DecryptionStream.OpenAsync(streamDownloadResponse.Stream, streamDownloadResponse.StreamSize, symmetricKey, CryptoProvider.StreamEncryptionFactory),
             DownloadTransferCiphertextError.UnknownError);
     }
 }
diff --git a/Crypter.Common.Client/Transfer/Handlers/DownloadMessageHandler.cs b/Crypter.Common.Client/Transfer/Handlers/DownloadMessageHandler.cs
@@ -35,6 +35,7 @@
 using Crypter.Common.Contracts.Features.Transfer;
 using Crypter.Common.Enums;
 using Crypter.Crypto.Common;
+using Crypter.Crypto.Common.StreamEncryption;
 using EasyMonads;
 
 namespace Crypter.Common.Client.Transfer.Handlers;
@@ -83,12 +84,23 @@ public async Task<Either<DownloadTransferCiphertextError, string>> DownloadCiphe
         };
 #pragma warning restore CS8524
 
-        return response.Match<Either<DownloadTransferCiphertextError, string>>(
-            left => left,
-            right =>
+        return await response.MatchAsync<Either<DownloadTransferCiphertextError, string>>(
+            error => error,
+            async streamDownloadResponse =>
             {
-                byte[] plaintext = Decrypt(symmetricKey, right.Stream, right.StreamSize);
-                return Encoding.UTF8.GetString(plaintext);
+                await using DecryptionStream decryptionStream = await DecryptionStream.OpenAsync(streamDownloadResponse.Stream,
+                    streamDownloadResponse.StreamSize, symmetricKey, CryptoProvider.StreamEncryptionFactory);
+
+                byte[] plaintextBuffer = new byte[checked((int)streamDownloadResponse.StreamSize)];
+                int plaintextPosition = 0;
+                int bytesRead;
+                do
+                {
+                    bytesRead = await decryptionStream.ReadAsync(plaintextBuffer.AsMemory(plaintextPosition));
+                    plaintextPosition += bytesRead;
+                } while (bytesRead > 0);
+
+                return Encoding.UTF8.GetString(plaintextBuffer[..plaintextPosition]);
             },
             DownloadTransferCiphertextError.UnknownError);
     }