From 2bd65b27e1f3624549457a91c1b39dba1f521f80 Mon Sep 17 00:00:00 2001
From: Klemens Morgenstern <klemens.d.morgenstern@gmail.com>
Date: Mon, 20 Feb 2023 13:58:07 +0800
Subject: [PATCH] awaitable server close fix.

Closes #2637
---
 .../awaitable/http_server_awaitable.cpp       | 66 ++++++++++---------
 1 file changed, 35 insertions(+), 31 deletions(-)

diff --git a/example/http/server/awaitable/http_server_awaitable.cpp b/example/http/server/awaitable/http_server_awaitable.cpp
index 64961da5..47ae01dc 100644
--- a/example/http/server/awaitable/http_server_awaitable.cpp
+++ b/example/http/server/awaitable/http_server_awaitable.cpp
@@ -215,37 +215,37 @@ do_session(
     tcp_stream stream,
     std::shared_ptr<std::string const> doc_root)
 {
-    beast::error_code ec;
-
     // This buffer is required to persist across reads
     beast::flat_buffer buffer;
 
     // This lambda is used to send messages
-    for(;;)
     try
     {
-        // Set the timeout.
-        stream.expires_after(std::chrono::seconds(30));
-
-        // Read a request
-        http::request<http::string_body> req;
-        co_await http::async_read(stream, buffer, req);
-
-        // Handle the request
-        http::message_generator msg =
-            handle_request(*doc_root, std::move(req));
-
-        // Determine if we should close the connection
-        bool keep_alive = msg.keep_alive();
-
-        // Send the response
-        co_await beast::async_write(stream, std::move(msg), net::use_awaitable);
-
-        if(! keep_alive)
+        for(;;)
         {
-            // This means we should close the connection, usually because
-            // the response indicated the "Connection: close" semantic.
-            break;
+            // Set the timeout.
+            stream.expires_after(std::chrono::seconds(30));
+
+            // Read a request
+            http::request<http::string_body> req;
+            co_await http::async_read(stream, buffer, req);
+
+            // Handle the request
+            http::message_generator msg =
+                handle_request(*doc_root, std::move(req));
+
+            // Determine if we should close the connection
+            bool keep_alive = msg.keep_alive();
+
+            // Send the response
+            co_await beast::async_write(stream, std::move(msg), net::use_awaitable);
+
+            if(! keep_alive)
+            {
+                // This means we should close the connection, usually because
+                // the response indicated the "Connection: close" semantic.
+                break;
+            }
         }
     }
     catch (boost::system::system_error & se)
@@ -255,9 +255,12 @@ do_session(
     }
 
     // Send a TCP shutdown
+    beast::error_code ec;
     stream.socket().shutdown(tcp::socket::shutdown_send, ec);
 
     // At this point the connection is closed gracefully
+    // we ignore the error because the client might have
+    // dropped the connection already.
 }
 
 //------------------------------------------------------------------------------
@@ -287,13 +290,14 @@ do_listen(
                 do_session(tcp_stream(co_await acceptor.async_accept()), doc_root),
                 [](std::exception_ptr e)
                 {
-                    try
-                    {
-                        std::rethrow_exception(e);
-                    }
-                    catch (std::exception &e) {
-                        std::cerr << "Error in session: " << e.what() << "\n";
-                    }
+                    if (e)
+                        try
+                        {
+                            std::rethrow_exception(e);
+                        }
+                        catch (std::exception &e) {
+                            std::cerr << "Error in session: " << e.what() << "\n";
+                        }
                 });
 
 }