details: http://hg.nginx.org/nginx/rev/8666da1ecf33
branches:
changeset: 7036:8666da1ecf33
user: Piotr Sikora <piotrsikora@google.com>
date: Fri Mar 24 03:37:34 2017 -0700
description:
Headers filter: added "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@google.com>

diffstat:

src/http/modules/ngx_http_headers_filter_module.c | 166 ++++++++++++++++++---
1 files changed, 143 insertions(+), 23 deletions(-)

diffs (255 lines):

diff --git a/src/http/modules/ngx_http_headers_filter_module.c b/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;


@@ -105,7 +106,15 @@ static ngx_command_t ngx_http_headers_f
|NGX_CONF_TAKE23,
ngx_http_headers_add,
NGX_HTTP_LOC_CONF_OFFSET,
- 0,
+ offsetof(ngx_http_headers_conf_t, headers),
+ 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,
+ NGX_HTTP_LOC_CONF_OFFSET,
+ offsetof(ngx_http_headers_conf_t, trailers),
NULL },

ngx_null_command
@@ -144,6 +153,7 @@ ngx_module_t ngx_http_headers_filter_mo


static ngx_http_output_header_filter_pt ngx_http_next_header_filter;
+static ngx_http_output_body_filter_pt ngx_http_next_body_filter;


static ngx_int_t
@@ -154,10 +164,15 @@ ngx_http_headers_filter(ngx_http_request
ngx_http_header_val_t *h;
ngx_http_headers_conf_t *conf;

+ 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);
}
@@ -206,11 +221,101 @@ ngx_http_headers_filter(ngx_http_request
}
}

+ if (conf->trailers) {
+ h = conf->trailers->elts;
+ for (i = 0; i < conf->trailers->nelts; i++) {
+
+ if (!safe_status && !h[i].always) {
+ continue;
+ }
+
+ r->expect_trailers = 1;
+ break;
+ }
+ }
+
return ngx_http_next_header_filter(r);
}


static ngx_int_t
+ngx_http_trailers_filter(ngx_http_request_t *r, ngx_chain_t *in)
+{
+ ngx_str_t value;
+ ngx_uint_t i, safe_status;
+ ngx_chain_t *cl;
+ 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 (in == NULL
+ || conf->trailers == NULL
+ || !r->expect_trailers
+ || r->header_only)
+ {
+ return ngx_http_next_body_filter(r, in);
+ }
+
+ for (cl = in; cl; cl = cl->next) {
+ if (cl->buf->last_buf) {
+ break;
+ }
+ }
+
+ if (cl == NULL) {
+ return ngx_http_next_body_filter(r, in);
+ }
+
+ 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:
+ case NGX_HTTP_PERMANENT_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_http_next_body_filter(r, in);
+}
+
+
+static ngx_int_t
ngx_http_set_expires(ngx_http_request_t *r, ngx_http_headers_conf_t *conf)
{
char *err;
@@ -557,6 +662,7 @@ 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;
*/
@@ -587,6 +693,10 @@ ngx_http_headers_merge_conf(ngx_conf_t *
conf->headers = prev->headers;
}

+ if (conf->trailers == NULL) {
+ conf->trailers = prev->trailers;
+ }
+
return NGX_CONF_OK;
}

@@ -597,6 +707,9 @@ ngx_http_headers_filter_init(ngx_conf_t
ngx_http_next_header_filter = ngx_http_top_header_filter;
ngx_http_top_header_filter = ngx_http_headers_filter;

+ ngx_http_next_body_filter = ngx_http_top_body_filter;
+ ngx_http_top_body_filter = ngx_http_trailers_filter;
+
return NGX_OK;
}

@@ -674,42 +787,49 @@ ngx_http_headers_add(ngx_conf_t *cf, ngx
{
ngx_http_headers_conf_t *hcf = conf;

- ngx_str_t *value;
- ngx_uint_t i;
- ngx_http_header_val_t *hv;
- ngx_http_set_header_t *set;
- ngx_http_compile_complex_value_t ccv;
+ ngx_str_t *value;
+ ngx_uint_t i;
+ ngx_array_t **headers;
+ ngx_http_header_val_t *hv;
+ ngx_http_set_header_t *set;
+ ngx_http_compile_complex_value_t ccv;

value = cf->args->elts;

- if (hcf->headers == NULL) {
- hcf->headers = ngx_array_create(cf->pool, 1,
- sizeof(ngx_http_header_val_t));
- if (hcf->headers == NULL) {
+ headers = (ngx_array_t **) ((char *) hcf + cmd->offset);
+
+ if (*headers == NULL) {
+ *headers = ngx_array_create(cf->pool, 1,
+ sizeof(ngx_http_header_val_t));
+ if (*headers == NULL) {
return NGX_CONF_ERROR;
}
}

- hv = ngx_array_push(hcf->headers);
+ hv = ngx_array_push(*headers);
if (hv == NULL) {
return NGX_CONF_ERROR;
}

hv->key = value[1];
- hv->handler = ngx_http_add_header;
+ hv->handler = NULL;
hv->offset = 0;
hv->always = 0;

- set = ngx_http_set_headers;
- for (i = 0; set[i].name.len; i++) {
- if (ngx_strcasecmp(value[1].data, set[i].name.data) != 0) {
- continue;
+ if (headers == &hcf->headers) {
+ hv->handler = ngx_http_add_header;
+
+ set = ngx_http_set_headers;
+ for (i = 0; set[i].name.len; i++) {
+ if (ngx_strcasecmp(value[1].data, set[i].name.data) != 0) {
+ continue;
+ }
+
+ hv->offset = set[i].offset;
+ hv->handler = set[i].handler;
+
+ break;
}
-
- hv->offset = set[i].offset;
- hv->handler = set[i].handler;
-
- break;
}

if (value[2].len == 0) {
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