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/*
* Copyright (C) Igor Sysoev
*/
#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>
typedef struct {
time_t expires;
} ngx_http_headers_conf_t;
#define NGX_HTTP_EXPIRES_UNSET -2147483647
#define NGX_HTTP_EXPIRES_OFF -2147483646
#define NGX_HTTP_EXPIRES_EPOCH -2147483645
static ngx_int_t ngx_http_headers_filter_init(ngx_cycle_t *cycle);
static void *ngx_http_headers_create_conf(ngx_conf_t *cf);
static char *ngx_http_headers_merge_conf(ngx_conf_t *cf,
void *parent, void *child);
static char *ngx_http_headers_expires(ngx_conf_t *cf, ngx_command_t *cmd,
void *conf);
static ngx_command_t ngx_http_headers_filter_commands[] = {
{ ngx_string("expires"),
NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
ngx_http_headers_expires,
NGX_HTTP_LOC_CONF_OFFSET,
0,
NULL},
ngx_null_command
};
static ngx_http_module_t ngx_http_headers_filter_module_ctx = {
NULL, /* preconfiguration */
NULL, /* postconfiguration */
NULL, /* create main configuration */
NULL, /* init main configuration */
NULL, /* create server configuration */
NULL, /* merge server configuration */
ngx_http_headers_create_conf, /* create location configuration */
ngx_http_headers_merge_conf /* merge location configuration */
};
ngx_module_t ngx_http_headers_filter_module = {
NGX_MODULE_V1,
&ngx_http_headers_filter_module_ctx, /* module context */
ngx_http_headers_filter_commands, /* module directives */
NGX_HTTP_MODULE, /* module type */
NULL, /* init master */
ngx_http_headers_filter_init, /* init module */
NULL, /* init process */
NULL, /* init thread */
NULL, /* exit thread */
NULL, /* exit process */
NULL, /* exit master */
NGX_MODULE_V1_PADDING
};
static ngx_http_output_header_filter_pt ngx_http_next_header_filter;
static ngx_int_t
ngx_http_headers_filter(ngx_http_request_t *r)
{
size_t len;
ngx_uint_t i;
ngx_table_elt_t *expires, *cc, **ccp;
ngx_http_headers_conf_t *conf;
if ((r->headers_out.status != NGX_HTTP_OK
&& r->headers_out.status != NGX_HTTP_NOT_MODIFIED)
|| 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) {
expires = r->headers_out.expires;
if (expires == NULL) {
expires = ngx_list_push(&r->headers_out.headers);
if (expires == NULL) {
return NGX_ERROR;
}
r->headers_out.expires = expires;
expires->hash = 1;
expires->key.len = sizeof("Expires") - 1;
expires->key.data = (u_char *) "Expires";
}
len = sizeof("Mon, 28 Sep 1970 06:00:00 GMT");
expires->value.len = len - 1;
ccp = r->headers_out.cache_control.elts;
if (ccp == NULL) {
if (ngx_array_init(&r->headers_out.cache_control, r->pool,
1, sizeof(ngx_table_elt_t *)) != NGX_OK)
{
return NGX_ERROR;
}
ccp = ngx_array_push(&r->headers_out.cache_control);
if (ccp == NULL) {
return NGX_ERROR;
}
cc = ngx_list_push(&r->headers_out.headers);
if (cc == NULL) {
return NGX_ERROR;
}
cc->hash = 1;
cc->key.len = sizeof("Cache-Control") - 1;
cc->key.data = (u_char *) "Cache-Control";
*ccp = cc;
} else {
for (i = 1; i < r->headers_out.cache_control.nelts; i++) {
ccp[i]->hash = 0;
}
cc = ccp[0];
}
if (conf->expires == NGX_HTTP_EXPIRES_EPOCH) {
expires->value.data = (u_char *) "Thu, 01 Jan 1970 00:00:01 GMT";
cc->value.len = sizeof("no-cache") - 1;
cc->value.data = (u_char *) "no-cache";
} else {
expires->value.data = ngx_palloc(r->pool, len);
if (expires->value.data == NULL) {
return NGX_ERROR;
}
if (conf->expires == 0) {
ngx_memcpy(expires->value.data, ngx_cached_http_time.data,
ngx_cached_http_time.len + 1);
cc->value.len = sizeof("max-age=0") - 1;
cc->value.data = (u_char *) "max-age=0";
} else {
ngx_http_time(expires->value.data, ngx_time() + conf->expires);
if (conf->expires < 0) {
cc->value.len = sizeof("no-cache") - 1;
cc->value.data = (u_char *) "no-cache";
} else {
cc->value.data = ngx_palloc(r->pool, sizeof("max-age=")
+ NGX_TIME_T_LEN + 1);
if (cc->value.data == NULL) {
return NGX_ERROR;
}
cc->value.len = ngx_sprintf(cc->value.data, "max-age=%T",
conf->expires)
- cc->value.data;
}
}
}
}
return ngx_http_next_header_filter(r);
}
static ngx_int_t
ngx_http_headers_filter_init(ngx_cycle_t *cycle)
{
ngx_http_next_header_filter = ngx_http_top_header_filter;
ngx_http_top_header_filter = ngx_http_headers_filter;
return NGX_OK;
}
static void *
ngx_http_headers_create_conf(ngx_conf_t *cf)
{
ngx_http_headers_conf_t *conf;
conf = ngx_palloc(cf->pool, sizeof(ngx_http_headers_conf_t));
if (conf == NULL) {
return NGX_CONF_ERROR;
}
conf->expires = NGX_HTTP_EXPIRES_UNSET;
return conf;
}
static char *
ngx_http_headers_merge_conf(ngx_conf_t *cf, void *parent, void *child)
{
ngx_http_headers_conf_t *prev = parent;
ngx_http_headers_conf_t *conf = child;
if (conf->expires == NGX_HTTP_EXPIRES_UNSET) {
conf->expires = (prev->expires == NGX_HTTP_EXPIRES_UNSET) ?
NGX_HTTP_EXPIRES_OFF : prev->expires;
}
return NGX_CONF_OK;
}
static char *
ngx_http_headers_expires(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
ngx_http_headers_conf_t *hcf = conf;
ngx_uint_t minus;
ngx_str_t *value;
if (hcf->expires != NGX_HTTP_EXPIRES_UNSET) {
return "is duplicate";
}
value = cf->args->elts;
if (ngx_strcmp(value[1].data, "epoch") == 0) {
hcf->expires = NGX_HTTP_EXPIRES_EPOCH;
return NGX_CONF_OK;
}
if (ngx_strcmp(value[1].data, "off") == 0) {
hcf->expires = NGX_HTTP_EXPIRES_OFF;
return NGX_CONF_OK;
}
if (value[1].data[0] == '+') {
value[1].data++;
value[1].len--;
minus = 0;
} else if (value[1].data[0] == '-') {
value[1].data++;
value[1].len--;
minus = 1;
} else {
minus = 0;
}
hcf->expires = ngx_parse_time(&value[1], 1);
if (hcf->expires == NGX_ERROR) {
return "invalid value";
}
if (hcf->expires == NGX_PARSE_LARGE_TIME) {
return "value must be less than 68 years";
}
if (minus) {
hcf->expires = - hcf->expires;
}
return NGX_CONF_OK;
}
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