1 files changed, 90 insertions, 0 deletions

diff --git a/src/lib/response_for_upgrade.c b/src/lib/response_for_upgrade.c
new file mode 100644
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--- /dev/null
+++ b/src/lib/response_for_upgrade.c
@@ -0,0 +1,90 @@
+/*
+  This file is part of libmicrohttpd
+  Copyright (C) 2007-2018 Daniel Pittman and Christian Grothoff
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with this library; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+/**
+ * @file lib/response_for_upgrade.c
+ * @brief implementation of MHD_response_for_upgrade()
+ * @author Christian Grothoff
+ */
+#include "internal.h"
+
+
+/**
+ * Create a response object that can be used for 101 UPGRADE
+ * responses, for example to implement WebSockets.  After sending the
+ * response, control over the data stream is given to the callback (which
+ * can then, for example, start some bi-directional communication).
+ * If the response is queued for multiple connections, the callback
+ * will be called for each connection.  The callback
+ * will ONLY be called after the response header was successfully passed
+ * to the OS; if there are communication errors before, the usual MHD
+ * connection error handling code will be performed.
+ *
+ * MHD will automatically set the correct HTTP status
+ * code (#MHD_HTTP_SWITCHING_PROTOCOLS).
+ * Setting correct HTTP headers for the upgrade must be done
+ * manually (this way, it is possible to implement most existing
+ * WebSocket versions using this API; in fact, this API might be useful
+ * for any protocol switch, not just WebSockets).  Note that
+ * draft-ietf-hybi-thewebsocketprotocol-00 cannot be implemented this
+ * way as the header "HTTP/1.1 101 WebSocket Protocol Handshake"
+ * cannot be generated; instead, MHD will always produce "HTTP/1.1 101
+ * Switching Protocols" (if the response code 101 is used).
+ *
+ * As usual, the response object can be extended with header
+ * information and then be used any number of times (as long as the
+ * header information is not connection-specific).
+ *
+ * @param upgrade_handler function to call with the "upgraded" socket
+ * @param upgrade_handler_cls closure for @a upgrade_handler
+ * @return NULL on error (i.e. invalid arguments, out of memory)
+ */
+struct MHD_Response *
+MHD_response_for_upgrade (MHD_UpgradeHandler upgrade_handler,
+                          void *upgrade_handler_cls)
+{
+  struct MHD_Response *response;
+
+  mhd_assert (NULL != upgrade_handler);
+  response = MHD_calloc_ (1,
+                          sizeof (struct MHD_Response));
+  if (NULL == response)
+    return NULL;
+  if (! MHD_mutex_init_ (&response->mutex))
+    {
+      free (response);
+      return NULL;
+    }
+  response->upgrade_handler = upgrade_handler;
+  response->upgrade_handler_cls = upgrade_handler_cls;
+  response->status_code = MHD_HTTP_SWITCHING_PROTOCOLS;
+  response->total_size = MHD_SIZE_UNKNOWN;
+  response->reference_count = 1;
+  if (MHD_NO ==
+      MHD_add_response_header (response,
+                               MHD_HTTP_HEADER_CONNECTION,
+                               "Upgrade"))
+    {
+      MHD_destroy_response (response);
+      return NULL;
+    }
+  return response;
+}
+
+/* end of response_for_upgrade.c */