[PATCH 2 of 3] Headers filter: add "add_trailer" directive
Piotr Sikora
piotrsikora at google.com
Mon Apr 3 09:32:12 UTC 2017
# HG changeset patch
# User Piotr Sikora <piotrsikora at google.com>
# Date 1490351854 25200
# Fri Mar 24 03:37:34 2017 -0700
# Node ID 5bab17ebe2b1f8ec42cf069bf484489c2a92c7a8
# Parent 8af81a0d66c0f69bcf501edcf10deed4c8f7fbd4
Headers filter: add "add_trailer" directive.
Trailers added using this directive are evaluated after response body
is processed by output filters (but before it's written to the wire),
so it's possible to use variables calculated from the response body
as the trailer value.
Signed-off-by: Piotr Sikora <piotrsikora at google.com>
diff -r 8af81a0d66c0 -r 5bab17ebe2b1 src/http/modules/ngx_http_chunked_filter_module.c
--- a/src/http/modules/ngx_http_chunked_filter_module.c
+++ b/src/http/modules/ngx_http_chunked_filter_module.c
@@ -256,6 +256,10 @@ ngx_http_chunked_create_trailers(ngx_htt
ngx_table_elt_t *header;
ngx_http_chunked_filter_ctx_t *ctx;
+ if (ngx_http_eval_trailers(r) != NGX_OK) {
+ return NULL;
+ }
+
len = 0;
part = &r->headers_out.trailers.part;
diff -r 8af81a0d66c0 -r 5bab17ebe2b1 src/http/modules/ngx_http_headers_filter_module.c
--- a/src/http/modules/ngx_http_headers_filter_module.c
+++ b/src/http/modules/ngx_http_headers_filter_module.c
@@ -48,6 +48,7 @@ typedef struct {
time_t expires_time;
ngx_http_complex_value_t *expires_value;
ngx_array_t *headers;
+ ngx_array_t *trailers;
} ngx_http_headers_conf_t;
@@ -72,6 +73,8 @@ static char *ngx_http_headers_expires(ng
void *conf);
static char *ngx_http_headers_add(ngx_conf_t *cf, ngx_command_t *cmd,
void *conf);
+static char *ngx_http_headers_add_trailer(ngx_conf_t *cf, ngx_command_t *cmd,
+ void *conf);
static ngx_http_set_header_t ngx_http_set_headers[] = {
@@ -108,6 +111,14 @@ static ngx_command_t ngx_http_headers_f
0,
NULL},
+ { ngx_string("add_trailer"),
+ NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_HTTP_LIF_CONF
+ |NGX_CONF_TAKE23,
+ ngx_http_headers_add_trailer,
+ NGX_HTTP_LOC_CONF_OFFSET,
+ 0,
+ NULL},
+
ngx_null_command
};
@@ -149,15 +160,24 @@ static ngx_http_output_header_filter_pt
static ngx_int_t
ngx_http_headers_filter(ngx_http_request_t *r)
{
- ngx_str_t value;
- ngx_uint_t i, safe_status;
- ngx_http_header_val_t *h;
- ngx_http_headers_conf_t *conf;
+ u_char *p, *data;
+ size_t len;
+ ngx_str_t value;
+ ngx_uint_t i, safe_status;
+ ngx_table_elt_t *t;
+ ngx_http_header_val_t *h;
+ ngx_http_headers_conf_t *conf;
+ ngx_http_core_loc_conf_t *clcf;
+
+ if (r != r->main) {
+ return ngx_http_next_header_filter(r);
+ }
conf = ngx_http_get_module_loc_conf(r, ngx_http_headers_filter_module);
- if ((conf->expires == NGX_HTTP_EXPIRES_OFF && conf->headers == NULL)
- || r != r->main)
+ if (conf->expires == NGX_HTTP_EXPIRES_OFF
+ && conf->headers == NULL
+ && conf->trailers == NULL)
{
return ngx_http_next_header_filter(r);
}
@@ -205,6 +225,84 @@ ngx_http_headers_filter(ngx_http_request
}
}
+ if (conf->trailers && r->allow_trailers) {
+
+ if (r->http_version < NGX_HTTP_VERSION_20) {
+ if (r->header_only
+ || r->headers_out.status == NGX_HTTP_NOT_MODIFIED
+ || r->headers_out.status == NGX_HTTP_NO_CONTENT
+ || r->headers_out.status < NGX_HTTP_OK
+ || r->method == NGX_HTTP_HEAD)
+ {
+ return ngx_http_next_header_filter(r);
+ }
+
+ clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
+
+ if (!clcf->chunked_transfer_encoding) {
+ return ngx_http_next_header_filter(r);
+ }
+ }
+
+ len = 0;
+
+ h = conf->trailers->elts;
+ for (i = 0; i < conf->trailers->nelts; i++) {
+
+ if (!safe_status && !h[i].always) {
+ continue;
+ }
+
+ if (h[i].value.value.len) {
+ len += h[i].key.len + sizeof(", ") - 1;
+ }
+ }
+
+ if (len == 0) {
+ return ngx_http_next_header_filter(r);
+ }
+
+ len -= sizeof(", ") - 1;
+
+ t = ngx_list_push(&r->headers_out.headers);
+ if (t == NULL) {
+ return NGX_ERROR;
+ }
+
+ data = ngx_pnalloc(r->pool, len);
+ if (data == NULL) {
+ return NGX_ERROR;
+ }
+
+ p = data;
+
+ h = conf->trailers->elts;
+ for (i = 0; i < conf->trailers->nelts; i++) {
+
+ if (!safe_status && !h[i].always) {
+ continue;
+ }
+
+ if (h[i].value.value.len) {
+ p = ngx_copy(p, h[i].key.data, h[i].key.len);
+
+ if (p == data + len) {
+ break;
+ }
+
+ *p++ = ','; *p++ = ' ';
+ }
+ }
+
+ ngx_str_set(&t->key, "Trailer");
+ t->value.data = data;
+ t->value.len = len;
+ t->hash = ngx_hash(ngx_hash(ngx_hash(ngx_hash(ngx_hash(
+ ngx_hash('t', 'r'), 'a'), 'i'), 'l'), 'e'), 'r');
+
+ r->expect_trailers = 1;
+ }
+
return ngx_http_next_header_filter(r);
}
@@ -541,6 +639,67 @@ ngx_http_set_response_header(ngx_http_re
}
+ngx_int_t
+ngx_http_eval_trailers(ngx_http_request_t *r)
+{
+ ngx_str_t value;
+ ngx_uint_t i, safe_status;
+ ngx_table_elt_t *t;
+ ngx_http_header_val_t *h;
+ ngx_http_headers_conf_t *conf;
+
+ conf = ngx_http_get_module_loc_conf(r, ngx_http_headers_filter_module);
+
+ if (conf->trailers == NULL) {
+ return NGX_OK;
+ }
+
+ switch (r->headers_out.status) {
+
+ case NGX_HTTP_OK:
+ case NGX_HTTP_CREATED:
+ case NGX_HTTP_NO_CONTENT:
+ case NGX_HTTP_PARTIAL_CONTENT:
+ case NGX_HTTP_MOVED_PERMANENTLY:
+ case NGX_HTTP_MOVED_TEMPORARILY:
+ case NGX_HTTP_SEE_OTHER:
+ case NGX_HTTP_NOT_MODIFIED:
+ case NGX_HTTP_TEMPORARY_REDIRECT:
+ safe_status = 1;
+ break;
+
+ default:
+ safe_status = 0;
+ break;
+ }
+
+ h = conf->trailers->elts;
+ for (i = 0; i < conf->trailers->nelts; i++) {
+
+ if (!safe_status && !h[i].always) {
+ continue;
+ }
+
+ if (ngx_http_complex_value(r, &h[i].value, &value) != NGX_OK) {
+ return NGX_ERROR;
+ }
+
+ if (value.len) {
+ t = ngx_list_push(&r->headers_out.trailers);
+ if (t == NULL) {
+ return NGX_ERROR;
+ }
+
+ t->key = h[i].key;
+ t->value = value;
+ t->hash = 1;
+ }
+ }
+
+ return NGX_OK;
+}
+
+
static void *
ngx_http_headers_create_conf(ngx_conf_t *cf)
{
@@ -555,6 +714,7 @@ ngx_http_headers_create_conf(ngx_conf_t
* set by ngx_pcalloc():
*
* conf->headers = NULL;
+ * conf->trailers = NULL;
* conf->expires_time = 0;
* conf->expires_value = NULL;
*/
@@ -585,6 +745,10 @@ ngx_http_headers_merge_conf(ngx_conf_t *
conf->headers = prev->headers;
}
+ if (conf->trailers == NULL) {
+ conf->trailers = prev->trailers;
+ }
+
return NGX_CONF_OK;
}
@@ -739,3 +903,63 @@ ngx_http_headers_add(ngx_conf_t *cf, ngx
return NGX_CONF_OK;
}
+
+
+static char *
+ngx_http_headers_add_trailer(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
+{
+ ngx_http_headers_conf_t *hcf = conf;
+
+ ngx_str_t *value;
+ ngx_http_header_val_t *hv;
+ ngx_http_compile_complex_value_t ccv;
+
+ value = cf->args->elts;
+
+ if (hcf->trailers == NULL) {
+ hcf->trailers = ngx_array_create(cf->pool, 1,
+ sizeof(ngx_http_header_val_t));
+ if (hcf->trailers == NULL) {
+ return NGX_CONF_ERROR;
+ }
+ }
+
+ hv = ngx_array_push(hcf->trailers);
+ if (hv == NULL) {
+ return NGX_CONF_ERROR;
+ }
+
+ hv->key = value[1];
+ hv->handler = NULL;
+ hv->offset = 0;
+ hv->always = 0;
+
+ if (value[2].len == 0) {
+ ngx_memzero(&hv->value, sizeof(ngx_http_complex_value_t));
+
+ } else {
+ ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t));
+
+ ccv.cf = cf;
+ ccv.value = &value[2];
+ ccv.complex_value = &hv->value;
+
+ if (ngx_http_compile_complex_value(&ccv) != NGX_OK) {
+ return NGX_CONF_ERROR;
+ }
+ }
+
+ if (cf->args->nelts == 3) {
+ return NGX_CONF_OK;
+ }
+
+ if (ngx_strcmp(value[3].data, "always") != 0) {
+ ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+ "invalid parameter \"%V\"", &value[3]);
+ return NGX_CONF_ERROR;
+ }
+
+ hv->always = 1;
+
+ return NGX_CONF_OK;
+}
diff -r 8af81a0d66c0 -r 5bab17ebe2b1 src/http/ngx_http.h
--- a/src/http/ngx_http.h
+++ b/src/http/ngx_http.h
@@ -143,6 +143,7 @@ ngx_int_t ngx_http_special_response_hand
ngx_int_t ngx_http_filter_finalize_request(ngx_http_request_t *r,
ngx_module_t *m, ngx_int_t error);
void ngx_http_clean_header(ngx_http_request_t *r);
+ngx_int_t ngx_http_eval_trailers(ngx_http_request_t *r);
ngx_int_t ngx_http_discard_request_body(ngx_http_request_t *r);
diff -r 8af81a0d66c0 -r 5bab17ebe2b1 src/http/v2/ngx_http_v2_filter_module.c
--- a/src/http/v2/ngx_http_v2_filter_module.c
+++ b/src/http/v2/ngx_http_v2_filter_module.c
@@ -667,6 +667,10 @@ ngx_http_v2_create_trailers_frame(ngx_ht
ngx_table_elt_t *header;
ngx_http_v2_out_frame_t *frame;
+ if (ngx_http_eval_trailers(r) != NGX_OK) {
+ return NGX_HTTP_V2_FRAME_ERROR;
+ }
+
len = 0;
tmp_len = 0;
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