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/*
* Copyright (C) Igor Sysoev
* Copyright (C) Nginx, Inc.
*/
#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>
static ngx_uint_t ngx_http_test_if_unmodified(ngx_http_request_t *r);
static ngx_uint_t ngx_http_test_if_modified(ngx_http_request_t *r);
static ngx_uint_t ngx_http_test_if_match(ngx_http_request_t *r,
ngx_table_elt_t *header, ngx_uint_t weak);
static ngx_int_t ngx_http_not_modified_filter_init(ngx_conf_t *cf);
static ngx_http_module_t ngx_http_not_modified_filter_module_ctx = {
NULL, /* preconfiguration */
ngx_http_not_modified_filter_init, /* postconfiguration */
NULL, /* create main configuration */
NULL, /* init main configuration */
NULL, /* create server configuration */
NULL, /* merge server configuration */
NULL, /* create location configuration */
NULL /* merge location configuration */
};
ngx_module_t ngx_http_not_modified_filter_module = {
NGX_MODULE_V1,
&ngx_http_not_modified_filter_module_ctx, /* module context */
NULL, /* module directives */
NGX_HTTP_MODULE, /* module type */
NULL, /* init master */
NULL, /* 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_not_modified_header_filter(ngx_http_request_t *r)
{
if (r->headers_out.status != NGX_HTTP_OK
|| r != r->main
|| r->disable_not_modified)
{
return ngx_http_next_header_filter(r);
}
if (r->headers_in.if_unmodified_since
&& !ngx_http_test_if_unmodified(r))
{
return ngx_http_filter_finalize_request(r, NULL,
NGX_HTTP_PRECONDITION_FAILED);
}
if (r->headers_in.if_match
&& !ngx_http_test_if_match(r, r->headers_in.if_match, 0))
{
return ngx_http_filter_finalize_request(r, NULL,
NGX_HTTP_PRECONDITION_FAILED);
}
if (r->headers_in.if_modified_since || r->headers_in.if_none_match) {
if (r->headers_in.if_modified_since
&& ngx_http_test_if_modified(r))
{
return ngx_http_next_header_filter(r);
}
if (r->headers_in.if_none_match
&& !ngx_http_test_if_match(r, r->headers_in.if_none_match, 1))
{
return ngx_http_next_header_filter(r);
}
/* not modified */
r->headers_out.status = NGX_HTTP_NOT_MODIFIED;
r->headers_out.status_line.len = 0;
r->headers_out.content_type.len = 0;
ngx_http_clear_content_length(r);
ngx_http_clear_accept_ranges(r);
if (r->headers_out.content_encoding) {
r->headers_out.content_encoding->hash = 0;
r->headers_out.content_encoding = NULL;
}
return ngx_http_next_header_filter(r);
}
return ngx_http_next_header_filter(r);
}
static ngx_uint_t
ngx_http_test_if_unmodified(ngx_http_request_t *r)
{
time_t iums;
if (r->headers_out.last_modified_time == (time_t) -1) {
return 0;
}
iums = ngx_parse_http_time(r->headers_in.if_unmodified_since->value.data,
r->headers_in.if_unmodified_since->value.len);
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"http iums:%T lm:%T", iums, r->headers_out.last_modified_time);
if (iums >= r->headers_out.last_modified_time) {
return 1;
}
return 0;
}
static ngx_uint_t
ngx_http_test_if_modified(ngx_http_request_t *r)
{
time_t ims;
ngx_http_core_loc_conf_t *clcf;
if (r->headers_out.last_modified_time == (time_t) -1) {
return 1;
}
clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
if (clcf->if_modified_since == NGX_HTTP_IMS_OFF) {
return 1;
}
ims = ngx_parse_http_time(r->headers_in.if_modified_since->value.data,
r->headers_in.if_modified_since->value.len);
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"http ims:%T lm:%T", ims, r->headers_out.last_modified_time);
if (ims == r->headers_out.last_modified_time) {
return 0;
}
if (clcf->if_modified_since == NGX_HTTP_IMS_EXACT
|| ims < r->headers_out.last_modified_time)
{
return 1;
}
return 0;
}
static ngx_uint_t
ngx_http_test_if_match(ngx_http_request_t *r, ngx_table_elt_t *header,
ngx_uint_t weak)
{
u_char *start, *end, ch;
ngx_str_t etag, *list;
list = &header->value;
if (list->len == 1 && list->data[0] == '*') {
return 1;
}
if (r->headers_out.etag == NULL) {
return 0;
}
etag = r->headers_out.etag->value;
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"http im:\"%V\" etag:%V", list, &etag);
if (weak
&& etag.len > 2
&& etag.data[0] == 'W'
&& etag.data[1] == '/')
{
etag.len -= 2;
etag.data += 2;
}
start = list->data;
end = list->data + list->len;
while (start < end) {
if (weak
&& end - start > 2
&& start[0] == 'W'
&& start[1] == '/')
{
start += 2;
}
if (etag.len > (size_t) (end - start)) {
return 0;
}
if (ngx_strncmp(start, etag.data, etag.len) != 0) {
goto skip;
}
start += etag.len;
while (start < end) {
ch = *start;
if (ch == ' ' || ch == '\t') {
start++;
continue;
}
break;
}
if (start == end || *start == ',') {
return 1;
}
skip:
while (start < end && *start != ',') { start++; }
while (start < end) {
ch = *start;
if (ch == ' ' || ch == '\t' || ch == ',') {
start++;
continue;
}
break;
}
}
return 0;
}
static ngx_int_t
ngx_http_not_modified_filter_init(ngx_conf_t *cf)
{
ngx_http_next_header_filter = ngx_http_top_header_filter;
ngx_http_top_header_filter = ngx_http_not_modified_header_filter;
return NGX_OK;
}
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