diff --git a/src/http-header-glue.c b/src/http-header-glue.c
index 5772c735..c6703a6b 100644
--- a/src/http-header-glue.c
+++ b/src/http-header-glue.c
@@ -31,7 +31,7 @@
 
 
 __attribute_cold__
-static int http_response_buffer_append_authority(request_st * const r, buffer * const o) {
+int http_response_buffer_append_authority(request_st * const r, buffer * const o) {
 	if (!buffer_string_is_empty(&r->uri.authority)) {
 		buffer_append_string_buffer(o, &r->uri.authority);
 	} else {
diff --git a/src/response.h b/src/response.h
index d5d30e70..905a0308 100644
--- a/src/response.h
+++ b/src/response.h
@@ -51,6 +51,7 @@ handler_t http_response_read(request_st *r, http_response_opts *opts, buffer *b,
 __attribute_cold__
 handler_t http_response_reqbody_read_error(request_st *r, int http_status);
 
+int http_response_buffer_append_authority(request_st *r, buffer *o);
 int http_response_redirect_to_directory(request_st *r, int status);
 int http_response_handle_cachable(request_st *r, const buffer *mtime);
 void http_response_body_clear(request_st *r, int preserve_length);