Added support for chunked transfer encoding in HTTP response (#232)

Author: Mourdraug

nanoFramework.System.Net.Http/Http/System.Net.HttpListenerResponse.cs

@@ -145,6 +145,11 @@ private void PrepareHeaders()
                 m_httpResponseHeaders.AddWithoutValidate(HttpKnownHeaderNames.Location, m_redirectLocation);
                 m_ResponseStatusCode = (int)HttpStatusCode.Redirect;
             }
+            
+            if (m_sendChunked) 
+            {
+                m_httpResponseHeaders.AddWithoutValidate(HttpKnownHeaderNames.TransferEncoding, "chunked");
+            }
         }
 
         /// <summary>
@@ -187,7 +192,7 @@ private void SendHeaders()
             Encoding encoder = Encoding.UTF8;
 
             byte[] statusLine = encoder.GetBytes(ComposeHTTPResponse());
-            m_clientStream.Write(statusLine, 0, statusLine.Length);
+            m_clientStream.m_Stream.Write(statusLine, 0, statusLine.Length);
 
             // Prepares/Updates WEB header collection.
             PrepareHeaders();
@@ -196,7 +201,7 @@ private void SendHeaders()
             byte[] pHeaders = m_httpResponseHeaders.ToByteArray();
 
             // Sends the headers
-            m_clientStream.Write(pHeaders, 0, pHeaders.Length);
+            m_clientStream.m_Stream.Write(pHeaders, 0, pHeaders.Length);
 
             m_WasResponseSent = true;
         }
@@ -334,6 +339,7 @@ public bool SendChunked
             {
                 ThrowIfResponseSent();
                 m_sendChunked = value;
+                m_clientStream.m_enableChunkedEncoding = value;
             }
         }
 
@@ -443,7 +449,7 @@ void IDisposable.Dispose()
                     // Iterates over list of client connections and remove its stream from it.
                     m_Listener.RemoveClientStream(m_clientStream);
 
-                    m_clientStream.Flush();
+                    m_clientStream.m_Stream.Flush();
 
                     // If KeepAlive is true,
                     if (m_KeepAlive)

nanoFramework.System.Net.Http/Http/System.Net._OutputNetworkStreamWrapper.cs

@@ -8,6 +8,7 @@ namespace System.Net
 {
     using System.IO;
     using System.Net.Sockets;
+    using System.Text;
 
     /// <summary>
     /// The OutputNetworkStreamWrapper is used to re-implement calls to  NetworkStream.Write
@@ -29,6 +30,11 @@ internal class OutputNetworkStreamWrapper : Stream
         /// </summary>
         internal NetworkStream m_Stream;
 
+        /// <summary>
+        /// If true causes all written data to be encoded as chunks
+        /// </summary>
+        internal bool m_enableChunkedEncoding = false;
+
         /// <summary>
         /// Type definition of delegate for sending of HTTP headers.
         /// </summary>
@@ -40,6 +46,11 @@ internal class OutputNetworkStreamWrapper : Stream
         /// </summary>
         private SendHeadersDelegate m_headersSend;
 
+        /// <summary>
+        /// EOL marker in chunked encoding
+        /// </summary>
+        private readonly byte[] EOLMarker = { 0xd, 0xa };
+
         /// <summary>
         /// Just passes parameters to the base.
         /// Socket is not owned by base NetworkStream
@@ -118,6 +129,35 @@ public override int WriteTimeout
             set { m_Stream.WriteTimeout = value; }
         }
 
+        /// <summary>
+        /// Writes to stream size of chunk and marks start of the chunk 
+        /// </summary>
+        private void WriteChunkStart(int size)
+        {
+            byte[] chunkLengthBytes = Encoding.UTF8.GetBytes($"{size:X}");
+            m_Stream.Write(chunkLengthBytes, 0, chunkLengthBytes.Length);
+            m_Stream.Write(EOLMarker, 0, EOLMarker.Length);
+        }
+
+        /// <summary>
+        /// Writes to stream marker - finish of the chunk
+        /// </summary>
+        private void WriteChunkEnd()
+        {
+            m_Stream.Write(EOLMarker, 0, EOLMarker.Length);
+        }
+
+        /// <summary>
+        /// Writes to stream marker - finish of all chunks
+        /// </summary>
+        private void WriteChunkFinish()
+        {
+            byte[] zero = { 0x30 };
+            m_Stream.Write(zero, 0, 1);
+            m_Stream.Write(EOLMarker, 0, EOLMarker.Length);
+            m_Stream.Write(EOLMarker, 0, EOLMarker.Length);
+        }
+
         /// <summary>
         /// Closes the stream. Verifies that HTTP response is sent before closing.
         /// </summary>
@@ -144,7 +184,12 @@ public override void Flush()
                 // Calls HttpListenerResponse.SendHeaders. HttpListenerResponse.SendHeaders sets m_headersSend to null.
                 m_headersSend();
             }
-            
+
+            if (m_enableChunkedEncoding)
+            {
+                WriteChunkFinish();
+            }
+
             // Need to check for null before using here
             m_Stream?.Flush();
         }
@@ -194,9 +239,26 @@ public override void SetLength(long value)
         /// <param name="value">Byte value to write.</param>
         public override void WriteByte(byte value)
         {
+            if (m_headersSend != null)
+            {
+                // Calls HttpListenerResponse.SendHeaders. HttpListenerResponse.SendHeaders sets m_headersSend to null.
+                m_headersSend();
+            }
+
+            if (m_enableChunkedEncoding)
+            {
+                WriteChunkStart(1);
+            }
+
             m_Stream.WriteByte(value);
+
+            if (m_enableChunkedEncoding)
+            {
+                WriteChunkEnd();
+            }
         }
 
+
         /// <summary>
         /// Re-implements writing of data to network stream.
         /// The only functionality - on first write it sends HTTP headers.
@@ -213,7 +275,17 @@ public override void Write(byte[] buffer, int offset, int size)
                 m_headersSend();
             }
 
-            m_Stream.Write(buffer, offset, size);
+            if (m_enableChunkedEncoding)
+            {
+                WriteChunkStart(size);
+            }
+
+            m_Stream.Write(buffer, 0, size);
+
+            if (m_enableChunkedEncoding)
+            {
+                WriteChunkEnd();
+            }
         }
     }
 }

version.json

@@ -1,6 +1,6 @@
 {
   "$schema": "https://raw.githubusercontent.com/dotnet/Nerdbank.GitVersioning/master/src/NerdBank.GitVersioning/version.schema.json",
-  "version": "1.3.5-preview.{height}",
+  "version": "1.3.6-preview.{height}",
   "assemblyVersion": {
     "precision": "revision"
   },
@@ -22,4 +22,4 @@
     "versionIncrement": "build",
     "firstUnstableTag": "preview"
   }
-}
+}