Added support for trailers in HTTP responses.

Example:

   ngx_table_elt_t  *h;

   h = ngx_list_push(&r->headers_out.trailers);
   if (h == NULL) {
       return NGX_ERROR;
   }

   ngx_str_set(&h->key, "Fun");
   ngx_str_set(&h->value, "with trailers");
   h->hash = ngx_hash_key_lc(h->key.data, h->key.len);

The code above adds "Fun: with trailers" trailer to the response.

Modules that want to emit trailers must set r->expect_trailers = 1
in header filter, otherwise they might not be emitted for HTTP/1.1
responses that aren't already chunked.

This change also adds $sent_trailer_* variables.

Signed-off-by: Piotr Sikora <piotrsikora@google.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/src/http/ngx_http_variables.c b/src/http/ngx_http_variables.c
index 6138819dd..cfb538a69 100644
--- a/src/http/ngx_http_variables.c
+++ b/src/http/ngx_http_variables.c
@@ -38,6 +38,8 @@ static ngx_int_t ngx_http_variable_unknown_header_in(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data);
 static ngx_int_t ngx_http_variable_unknown_header_out(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data);
+static ngx_int_t ngx_http_variable_unknown_trailer_out(ngx_http_request_t *r,
+    ngx_http_variable_value_t *v, uintptr_t data);
 static ngx_int_t ngx_http_variable_request_line(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data);
 static ngx_int_t ngx_http_variable_cookie(ngx_http_request_t *r,
@@ -365,6 +367,9 @@ static ngx_http_variable_t  ngx_http_core_variables[] = {
     { ngx_string("sent_http_"), NULL, ngx_http_variable_unknown_header_out,
       0, NGX_HTTP_VAR_PREFIX, 0 },
 
+    { ngx_string("sent_trailer_"), NULL, ngx_http_variable_unknown_trailer_out,
+      0, NGX_HTTP_VAR_PREFIX, 0 },
+
     { ngx_string("cookie_"), NULL, ngx_http_variable_cookie,
       0, NGX_HTTP_VAR_PREFIX, 0 },
 
@@ -934,6 +939,16 @@ ngx_http_variable_unknown_header_out(ngx_http_request_t *r,
 }
 
 
+static ngx_int_t
+ngx_http_variable_unknown_trailer_out(ngx_http_request_t *r,
+    ngx_http_variable_value_t *v, uintptr_t data)
+{
+    return ngx_http_variable_unknown_header(v, (ngx_str_t *) data,
+                                            &r->headers_out.trailers.part,
+                                            sizeof("sent_trailer_") - 1);
+}
+
+
 ngx_int_t
 ngx_http_variable_unknown_header(ngx_http_variable_value_t *v, ngx_str_t *var,
     ngx_list_part_t *part, size_t prefix)