defer choosing "Transfer-Encoding: chunked"

defer choosing "Transfer-Encoding: chunked" until response header
is about to be written

src/connections.c

@@ -341,7 +341,21 @@ static int connection_handle_write_prepare(server *srv, connection *con) {
 
 		if (((con->parsed_response & HTTP_CONTENT_LENGTH) == 0) &&
 		    ((con->response.transfer_encoding & HTTP_TRANSFER_ENCODING_CHUNKED) == 0)) {
-			con->keep_alive = 0;
+			if (con->request.http_version == HTTP_VERSION_1_1) {
+				off_t qlen = chunkqueue_length(con->write_queue);
+				con->response.transfer_encoding = HTTP_TRANSFER_ENCODING_CHUNKED;
+				if (qlen) {
+					/* create initial Transfer-Encoding: chunked segment */
+					buffer *b = srv->tmp_chunk_len;
+					buffer_string_set_length(b, 0);
+					buffer_append_uint_hex(b, (uintmax_t)qlen);
+					buffer_append_string_len(b, CONST_STR_LEN("\r\n"));
+					chunkqueue_prepend_buffer(con->write_queue, b);
+					chunkqueue_append_mem(con->write_queue, CONST_STR_LEN("\r\n"));
+				}
+			} else {
+				con->keep_alive = 0;
+			}
 		}
 
 		/**

src/mod_cgi.c

@@ -490,11 +490,6 @@ static int cgi_demux_response(server *srv, handler_ctx *hctx) {
 			if (is_header_end) {
 				if (!is_header) {
 					/* no header, but a body */
-
-					if (con->request.http_version == HTTP_VERSION_1_1) {
-						con->response.transfer_encoding = HTTP_TRANSFER_ENCODING_CHUNKED;
-					}
-
 					if (0 != http_chunk_append_buffer(srv, con, hctx->response_header)) {
 						return FDEVENT_HANDLED_ERROR;
 					}
@@ -531,12 +526,6 @@ static int cgi_demux_response(server *srv, handler_ctx *hctx) {
 						}
 					}
 
-					/* enable chunked-transfer-encoding */
-					if (con->request.http_version == HTTP_VERSION_1_1 &&
-					    !(con->parsed_response & HTTP_CONTENT_LENGTH)) {
-						con->response.transfer_encoding = HTTP_TRANSFER_ENCODING_CHUNKED;
-					}
-
 					if (blen > 0) {
 						if (0 != http_chunk_append_mem(srv, con, bstart, blen)) {
 							return FDEVENT_HANDLED_ERROR;

src/mod_fastcgi.c

@@ -2642,12 +2642,6 @@ static int fcgi_demux_response(server *srv, handler_ctx *hctx) {
 					hctx->send_content_body = 0; /* ignore the content */
 					break;
 				}
-
-				/* enable chunked-transfer-encoding */
-				if (con->request.http_version == HTTP_VERSION_1_1 &&
-				    !(con->parsed_response & HTTP_CONTENT_LENGTH)) {
-					con->response.transfer_encoding = HTTP_TRANSFER_ENCODING_CHUNKED;
-				}
 			}
 
 			if (hctx->send_content_body && !buffer_string_is_empty(packet.b)) {

src/mod_proxy.c

@@ -708,12 +708,6 @@ static int proxy_demux_response(server *srv, handler_ctx *hctx) {
 				/* parse the response header */
 				proxy_response_parse(srv, con, p, hctx->response_header);
 
-				/* enable chunked-transfer-encoding */
-				if (con->request.http_version == HTTP_VERSION_1_1 &&
-				    !(con->parsed_response & HTTP_CONTENT_LENGTH)) {
-					con->response.transfer_encoding = HTTP_TRANSFER_ENCODING_CHUNKED;
-				}
-
 				con->file_started = 1;
 				if (blen > 0) {
 					if (0 != http_chunk_append_mem(srv, con, c + 4, blen)) {

src/mod_scgi.c

@@ -1938,11 +1938,6 @@ static int scgi_demux_response(server *srv, handler_ctx *hctx) {
 			if (header_end) {
 				if (c == NULL) {
 					/* no header, but a body */
-
-					if (con->request.http_version == HTTP_VERSION_1_1) {
-						con->response.transfer_encoding = HTTP_TRANSFER_ENCODING_CHUNKED;
-					}
-
 					if (0 != http_chunk_append_buffer(srv, con, hctx->response_header)) {
 						/* error writing to tempfile;
 						 * truncate response or send 500 if nothing sent yet */
@@ -1965,12 +1960,6 @@ static int scgi_demux_response(server *srv, handler_ctx *hctx) {
 						}
 					}
 
-					/* enable chunked-transfer-encoding */
-					if (con->request.http_version == HTTP_VERSION_1_1 &&
-					    !(con->parsed_response & HTTP_CONTENT_LENGTH)) {
-						con->response.transfer_encoding = HTTP_TRANSFER_ENCODING_CHUNKED;
-					}
-
 					if (blen > 0) {
 						if (0 != http_chunk_append_mem(srv, con, hctx->response_header->ptr + hlen, blen)) {
 							/* error writing to tempfile;