From e368ad2efb64395716e1ecd0bac92c2767009984 Mon Sep 17 00:00:00 2001
From: Adam Gu <sprinfall@gmail.com>
Date: Tue, 31 Jul 2018 10:50:11 +0800
Subject: [PATCH] Close the socket after shutdown.

---
 example/rest_book_client/main.cc |  2 --
 webcc/http_connection.cc         | 34 ++++++++++++++++++++------------
 webcc/http_connection.h          |  3 +++
 3 files changed, 24 insertions(+), 15 deletions(-)

diff --git a/example/rest_book_client/main.cc b/example/rest_book_client/main.cc
index 9808306..edc641c 100644
--- a/example/rest_book_client/main.cc
+++ b/example/rest_book_client/main.cc
@@ -208,7 +208,5 @@ int main(int argc, char* argv[]) {
 
   list_client.ListBooks();
 
-  getchar();
-
   return 0;
 }
diff --git a/webcc/http_connection.cc b/webcc/http_connection.cc
index c00b570..4ecb179 100644
--- a/webcc/http_connection.cc
+++ b/webcc/http_connection.cc
@@ -100,23 +100,31 @@ void HttpConnection::AsyncWrite() {
 // This is ensured by Asio.
 void HttpConnection::WriteHandler(boost::system::error_code ec,
                                   std::size_t length) {
-  if (!ec) {
-    LOG_INFO("Response has been sent back, length: %u.", length);
-
-    // Initiate graceful connection closure.
-    LOG_INFO("Close socket gracefully...");
-    // TODO: shutdown(both) should be identical to close().
-    boost::system::error_code ec;
-    socket_.shutdown(boost::asio::ip::tcp::socket::shutdown_both, ec);
-    if (ec) {
-      LOG_ERRO("Failed to close socket.");
-    }
-  } else {
-    LOG_ERRO("Sending response error: %s", ec.message().c_str());
+  if (ec) {
+    LOG_ERRO("Socket write error: %s", ec.message().c_str());
 
     if (ec != boost::asio::error::operation_aborted) {
       Close();
     }
+  } else {
+    LOG_INFO("Response has been sent back, length: %u.", length);
+
+    Shutdown();
+    Close();  // Necessary even after shutdown!
+  }
+}
+
+// Socket close VS. Shutdown:
+//   https://stackoverflow.com/questions/4160347/close-vs-shutdown-socket
+void HttpConnection::Shutdown() {
+  LOG_INFO("Shutdown socket...");
+
+  // Initiate graceful connection closure.
+  boost::system::error_code ec;
+  socket_.shutdown(boost::asio::ip::tcp::socket::shutdown_both, ec);
+
+  if (ec) {
+    LOG_ERRO("Socket shutdown error: %s", ec.message().c_str());
   }
 }
 
diff --git a/webcc/http_connection.h b/webcc/http_connection.h
index 3d8896c..de9caaa 100644
--- a/webcc/http_connection.h
+++ b/webcc/http_connection.h
@@ -45,6 +45,9 @@ class HttpConnection : public std::enable_shared_from_this<HttpConnection> {
   void AsyncWrite();
   void WriteHandler(boost::system::error_code ec, std::size_t length);
 
+  // Shutdown the socket.
+  void Shutdown();
+
   // Socket for the connection.
   boost::asio::ip::tcp::socket socket_;