Fix HTTP/1.0 'Keep-Alive' handling in http_client (#1032)

Author: garethsb

Release/include/cpprest/http_msg.h

@@ -281,6 +281,8 @@ class http_msg_base
 
     virtual ~http_msg_base() {}
 
+    http::http_version http_version() const { return m_http_version; }
+
     http_headers& headers() { return m_headers; }
 
     _ASYNCRTIMP void set_body(const concurrency::streams::istream& instream, const utf8string& contentType);
@@ -419,6 +421,8 @@ class http_msg_base
     /// </remarks>
     _ASYNCRTIMP size_t _get_content_length_and_set_compression();
 
+    void _set_http_version(const http::http_version& http_version) { m_http_version = http_version; }
+
 protected:
     std::unique_ptr<http::compression::compress_provider> m_compressor;
     std::unique_ptr<http::compression::decompress_provider> m_decompressor;
@@ -444,6 +448,7 @@ class http_msg_base
     /// </summary>
     concurrency::streams::ostream m_outStream;
 
+    http::http_version m_http_version;
     http_headers m_headers;
     bool m_default_outstream;
 
@@ -838,8 +843,6 @@ class _http_request final : public http::details::http_msg_base, public std::ena
 
     _ASYNCRTIMP void set_request_uri(const uri&);
 
-    http::http_version http_version() const { return m_http_version; }
-
     const utility::string_t& remote_address() const { return m_remote_address; }
 
     const pplx::cancellation_token& cancellation_token() const { return m_cancellationToken; }
@@ -876,8 +879,6 @@ class _http_request final : public http::details::http_msg_base, public std::ena
 
     void _set_base_uri(const http::uri& base_uri) { m_base_uri = base_uri; }
 
-    void _set_http_version(const http::http_version& http_version) { m_http_version = http_version; }
-
     void _set_remote_address(const utility::string_t& remote_address) { m_remote_address = remote_address; }
 
 private:
@@ -906,8 +907,6 @@ class _http_request final : public http::details::http_msg_base, public std::ena
 
     pplx::task_completion_event<http_response> m_response;
 
-    http::http_version m_http_version;
-
     utility::string_t m_remote_address;
 };
 

Release/src/http/client/http_client_asio.cpp

@@ -1301,6 +1301,15 @@ class asio_context final : public request_context, public std::enable_shared_fro
                 return;
             }
 
+            web::http::http_version parsed_version = web::http::http_version::from_string(http_version);
+            m_response._get_impl()->_set_http_version(parsed_version);
+
+            // if HTTP version is 1.0 then disable 'Keep-Alive' by default
+            if (parsed_version == web::http::http_versions::HTTP_1_0)
+            {
+                m_connection->set_keep_alive(false);
+            }
+
             read_headers();
         }
         else
@@ -1391,11 +1400,14 @@ class asio_context final : public request_context, public std::enable_shared_fro
 
                 if (boost::iequals(name, header_names::connection))
                 {
-                    // This assumes server uses HTTP/1.1 so that 'Keep-Alive' is the default,
+                    // If the server uses HTTP/1.1, then 'Keep-Alive' is the default,
                     // so connection is explicitly closed only if we get "Connection: close".
-                    // We don't handle HTTP/1.0 server here. HTTP/1.0 server would need
-                    // to respond using 'Connection: Keep-Alive' every time.
-                    m_connection->set_keep_alive(!boost::iequals(value, U("close")));
+                    // If the server uses HTTP/1.0, it would need to respond using
+                    // 'Connection: Keep-Alive' every time.
+                    if (m_response._get_impl()->http_version() != web::http::http_versions::HTTP_1_0)
+                        m_connection->set_keep_alive(!boost::iequals(value, U("close")));
+                    else
+                        m_connection->set_keep_alive(boost::iequals(value, U("Keep-Alive")));
                 }
 
                 m_response.headers().add(utility::conversions::to_string_t(std::move(name)),

Release/src/http/common/http_msg.cpp

@@ -287,7 +287,11 @@ static const utility::char_t* stream_was_set_explicitly =
 static const utility::char_t* unsupported_charset =
     _XPLATSTR("Charset must be iso-8859-1, utf-8, utf-16, utf-16le, or utf-16be to be extracted.");
 
-http_msg_base::http_msg_base() : m_headers(), m_default_outstream(false) {}
+http_msg_base::http_msg_base()
+    : m_http_version(http::http_version{ 0, 0 })
+    , m_headers()
+    , m_default_outstream(false)
+{}
 
 void http_msg_base::_prepare_to_receive_data()
 {
@@ -1122,7 +1126,6 @@ details::_http_request::_http_request(http::method mtd)
     , m_initiated_response(0)
     , m_server_context()
     , m_cancellationToken(pplx::cancellation_token::none())
-    , m_http_version(http::http_version {0, 0})
 {
     if (m_method.empty())
     {
@@ -1134,7 +1137,6 @@ details::_http_request::_http_request(std::unique_ptr<http::details::_http_serve
     : m_initiated_response(0)
     , m_server_context(std::move(server_context))
     , m_cancellationToken(pplx::cancellation_token::none())
-    , m_http_version(http::http_version {0, 0})
 {
 }