From: Gauthier Haderer <ghaderer@wyplay.com>

Date: Mon, 15 Oct 2018 14:11:39 +0200
Subject: [PATCH] Add response flag to force version to 1.0 and maintain
 connection management.

The existing MHD_RF_HTTP_VERSION_1_0_ONLY flag already changes MHD's
behavior to apply HTTP 1.0 rules for connection management. When
enabled, MHD sends a response using the same version as used in the
request (is this normal?).

What I want is MHD responding as a HTTP 1.0 server with support for
connection management headers would do. This is what the
MHD_RF_HTTP_VERSION_1_0_RESPONSE response flag is for.

You can even combine it with MHD_RF_HTTP_VERSION_1_0_ONLY to change the
response's HTTP version while maintaining strict compliance with HTTP
1.0 regarding connection management.

This solution is not perfect as this flag is set on the response which
is created after header processing. So MHD will behave as a HTTP 1.1
server until the response is queued. It means that an invalid HTTP 1.1
request will fail even if the response is sent with HTTP 1.0 and the
request would be valid if interpreted with this version. For example,
this request will fail in strict mode:

GET /dummy HTTP/1.1

as the Host header is missing and is mandatory in HTTP 1.1, but it
should succeed when interpreted with HTTP 1.0.

I don't think this is a big issue in practice. Besides, being able to
change the HTTP version on a response basis is really convenient when
using MHD in a test framework where we need to validate a client against
HTTP 1.1 AND HTTP 1.0.

4 files changed, 48 insertions, 3 deletions

diff --git a/ChangeLog b/ChangeLog
index eb273daf..b8d2c8f5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Oct 16 20:43:41 CEST 2018
+        Add MHD_RF_HTTP_VERSION_1_0_RESPONSE option to make MHD
+        act more like an HTTP/1.0 server. -GH
+
 Fri Oct  5 18:44:45 CEST 2018
         MHD_add_response_header() now prevents applications from
         setting a "Transfer-Encoding" header to values other than
diff --git a/doc/libmicrohttpd.texi b/doc/libmicrohttpd.texi
index b61c94ff..2ecb64e6 100644
--- a/doc/libmicrohttpd.texi
+++ b/doc/libmicrohttpd.texi
@@ -1144,6 +1144,33 @@ Only respond in conservative HTTP 1.0-mode.   In particular,
 do not (automatically) sent "Connection" headers and always
 close the connection after generating the response.
 
+By default, MHD will respond using the same HTTP version which
+was set in the request. You can also set the
+@code{MHD_RF_HTTP_VERSION_1_0_RESPONSE} flag to force version 1.0
+in the response.
+
+@item MHD_RF_HTTP_VERSION_1_0_RESPONSE
+Only respond in HTTP 1.0-mode. Contrary to the
+@code{MHD_RF_HTTP_VERSION_1_0_ONLY} flag, the response's HTTP version will
+always be set to 1.0 and ``Connection'' headers are still supported.
+
+You can even combine this option with MHD_RF_HTTP_VERSION_1_0_ONLY to
+change the response's HTTP version while maintaining strict compliance
+with HTTP 1.0 regarding connection management.
+
+This solution is not perfect as this flag is set on the response which
+is created after header processing. So MHD will behave as a HTTP 1.1
+server until the response is queued. It means that an invalid HTTP 1.1
+request will fail even if the response is sent with HTTP 1.0 and the
+request would be valid if interpreted with this version. For example,
+this request will fail in strict mode:
+
+@verbatim
+GET / HTTP/1.1
+@end verbatim
+
+as the ``Host'' header is missing and is mandatory in HTTP 1.1, but it
+should succeed when interpreted with HTTP 1.0.
 @end table
 @end deftp
 
diff --git a/src/include/microhttpd.h b/src/include/microhttpd.h
index dae41fba..70ecd6e9 100644
--- a/src/include/microhttpd.h
+++ b/src/include/microhttpd.h
@@ -2623,8 +2623,19 @@ enum MHD_ResponseFlags
    * Only respond in conservative HTTP 1.0-mode.   In particular,
    * do not (automatically) sent "Connection" headers and always
    * close the connection after generating the response.
+   * By default, MHD will respond using the same HTTP version which
+   * was set in the request. You can also set the
+   * #MHD_RF_HTTP_VERSION_1_0_RESPONSE flag to force version 1.0
+   * in the response.
    */
-  MHD_RF_HTTP_VERSION_1_0_ONLY = 1
+  MHD_RF_HTTP_VERSION_1_0_ONLY = 1,
+
+  /**
+   * Only respond in HTTP 1.0-mode. Contrary to the
+   * #MHD_RF_HTTP_VERSION_1_0_ONLY flag, the response's HTTP version will
+   * always be set to 1.0 and "Connection" headers are still supported.
+   */
+  MHD_RF_HTTP_VERSION_1_0_RESPONSE = 2
 
 };
 
diff --git a/src/microhttpd/connection.c b/src/microhttpd/connection.c
index 60dc5eb4..3e641d15 100644
--- a/src/microhttpd/connection.c
+++ b/src/microhttpd/connection.c
@@ -1274,7 +1274,9 @@ keepalive_possible (struct MHD_Connection *connection)
     return MHD_NO;
 
   if (MHD_str_equal_caseless_(connection->version,
-                              MHD_HTTP_VERSION_1_1))
+                              MHD_HTTP_VERSION_1_1) &&
+      ( (NULL == connection->response) ||
+        (0 == (connection->response->flags & MHD_RF_HTTP_VERSION_1_0_RESPONSE) ) ) )
     {
       if (MHD_lookup_header_s_token_ci (connection,
                                         MHD_HTTP_HEADER_CONNECTION,
@@ -1449,7 +1451,8 @@ build_header_response (struct MHD_Connection *connection)
                      (0 != (connection->responseCode & MHD_ICY_FLAG))
                      ? "ICY"
                      : ( (MHD_str_equal_caseless_ (MHD_HTTP_VERSION_1_0,
-                                                   connection->version))
+                                                   connection->version) ||
+                       (0 != (connection->response->flags & MHD_RF_HTTP_VERSION_1_0_RESPONSE)) )
                          ? MHD_HTTP_VERSION_1_0
                          : MHD_HTTP_VERSION_1_1),
                      rc,