details: http://hg.nginx.org/nginx/rev/43ccaf8e8728
branches:
changeset: 5441:43ccaf8e8728
user: Maxim Dounin <mdounin@mdounin.ru>
date: Mon Nov 18 20:48:22 2013 +0400
description:
Upstream: cache revalidation with conditional requests.

The following new directives are introduced: proxy_cache_revalidate,
fastcgi_cache_revalidate, scgi_cache_revalidate, uwsgi_cache_revalidate.
Default is off. When set to on, they enable cache revalidation using
conditional requests with If-Modified-Since for expired cache items.

As of now, no attempts are made to merge headers given in a 304 response
during cache revalidation with headers previously stored in a cache item.
Headers in a 304 response are only used to calculate new validity time
of a cache item.

diffstat:

src/http/modules/ngx_http_fastcgi_module.c | 14 +++-
src/http/modules/ngx_http_proxy_module.c | 14 +++-
src/http/modules/ngx_http_scgi_module.c | 14 +++-
src/http/modules/ngx_http_uwsgi_module.c | 14 +++-
src/http/ngx_http_cache.h | 6 +-
src/http/ngx_http_file_cache.c | 111 +++++++++++++++++++++++++++++
src/http/ngx_http_upstream.c | 85 ++++++++++++++++++++++
src/http/ngx_http_upstream.h | 2 +
8 files changed, 254 insertions(+), 6 deletions(-)

diffs (truncated from 459 to 300 lines):

diff --git a/src/http/modules/ngx_http_fastcgi_module.c b/src/http/modules/ngx_http_fastcgi_module.c
--- a/src/http/modules/ngx_http_fastcgi_module.c
+++ b/src/http/modules/ngx_http_fastcgi_module.c
@@ -405,6 +405,13 @@ static ngx_command_t ngx_http_fastcgi_c
offsetof(ngx_http_fastcgi_loc_conf_t, upstream.cache_lock_timeout),
NULL },

+ { ngx_string("fastcgi_cache_revalidate"),
+ NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
+ ngx_conf_set_flag_slot,
+ NGX_HTTP_LOC_CONF_OFFSET,
+ offsetof(ngx_http_fastcgi_loc_conf_t, upstream.cache_revalidate),
+ NULL },
+
#endif

{ ngx_string("fastcgi_temp_path"),
@@ -563,7 +570,8 @@ static ngx_str_t ngx_http_fastcgi_hide_
#if (NGX_HTTP_CACHE)

static ngx_keyval_t ngx_http_fastcgi_cache_headers[] = {
- { ngx_string("HTTP_IF_MODIFIED_SINCE"), ngx_string("") },
+ { ngx_string("HTTP_IF_MODIFIED_SINCE"),
+ ngx_string("$upstream_cache_last_modified") },
{ ngx_string("HTTP_IF_UNMODIFIED_SINCE"), ngx_string("") },
{ ngx_string("HTTP_IF_NONE_MATCH"), ngx_string("") },
{ ngx_string("HTTP_IF_MATCH"), ngx_string("") },
@@ -2336,6 +2344,7 @@ ngx_http_fastcgi_create_loc_conf(ngx_con
conf->upstream.cache_valid = NGX_CONF_UNSET_PTR;
conf->upstream.cache_lock = NGX_CONF_UNSET;
conf->upstream.cache_lock_timeout = NGX_CONF_UNSET_MSEC;
+ conf->upstream.cache_revalidate = NGX_CONF_UNSET;
#endif

conf->upstream.hide_headers = NGX_CONF_UNSET_PTR;
@@ -2582,6 +2591,9 @@ ngx_http_fastcgi_merge_loc_conf(ngx_conf
ngx_conf_merge_msec_value(conf->upstream.cache_lock_timeout,
prev->upstream.cache_lock_timeout, 5000);

+ ngx_conf_merge_value(conf->upstream.cache_revalidate,
+ prev->upstream.cache_revalidate, 0);
+
#endif

ngx_conf_merge_value(conf->upstream.pass_request_headers,
diff --git a/src/http/modules/ngx_http_proxy_module.c b/src/http/modules/ngx_http_proxy_module.c
--- a/src/http/modules/ngx_http_proxy_module.c
+++ b/src/http/modules/ngx_http_proxy_module.c
@@ -465,6 +465,13 @@ static ngx_command_t ngx_http_proxy_com
offsetof(ngx_http_proxy_loc_conf_t, upstream.cache_lock_timeout),
NULL },

+ { ngx_string("proxy_cache_revalidate"),
+ NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
+ ngx_conf_set_flag_slot,
+ NGX_HTTP_LOC_CONF_OFFSET,
+ offsetof(ngx_http_proxy_loc_conf_t, upstream.cache_revalidate),
+ NULL },
+
#endif

{ ngx_string("proxy_temp_path"),
@@ -622,7 +629,8 @@ static ngx_keyval_t ngx_http_proxy_cach
{ ngx_string("Keep-Alive"), ngx_string("") },
{ ngx_string("Expect"), ngx_string("") },
{ ngx_string("Upgrade"), ngx_string("") },
- { ngx_string("If-Modified-Since"), ngx_string("") },
+ { ngx_string("If-Modified-Since"),
+ ngx_string("$upstream_cache_last_modified") },
{ ngx_string("If-Unmodified-Since"), ngx_string("") },
{ ngx_string("If-None-Match"), ngx_string("") },
{ ngx_string("If-Match"), ngx_string("") },
@@ -2454,6 +2462,7 @@ ngx_http_proxy_create_loc_conf(ngx_conf_
conf->upstream.cache_valid = NGX_CONF_UNSET_PTR;
conf->upstream.cache_lock = NGX_CONF_UNSET;
conf->upstream.cache_lock_timeout = NGX_CONF_UNSET_MSEC;
+ conf->upstream.cache_revalidate = NGX_CONF_UNSET;
#endif

conf->upstream.hide_headers = NGX_CONF_UNSET_PTR;
@@ -2710,6 +2719,9 @@ ngx_http_proxy_merge_loc_conf(ngx_conf_t
ngx_conf_merge_msec_value(conf->upstream.cache_lock_timeout,
prev->upstream.cache_lock_timeout, 5000);

+ ngx_conf_merge_value(conf->upstream.cache_revalidate,
+ prev->upstream.cache_revalidate, 0);
+
#endif

ngx_conf_merge_str_value(conf->method, prev->method, "");
diff --git a/src/http/modules/ngx_http_scgi_module.c b/src/http/modules/ngx_http_scgi_module.c
--- a/src/http/modules/ngx_http_scgi_module.c
+++ b/src/http/modules/ngx_http_scgi_module.c
@@ -262,6 +262,13 @@ static ngx_command_t ngx_http_scgi_comma
offsetof(ngx_http_scgi_loc_conf_t, upstream.cache_lock_timeout),
NULL },

+ { ngx_string("scgi_cache_revalidate"),
+ NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
+ ngx_conf_set_flag_slot,
+ NGX_HTTP_LOC_CONF_OFFSET,
+ offsetof(ngx_http_scgi_loc_conf_t, upstream.cache_revalidate),
+ NULL },
+
#endif

{ ngx_string("scgi_temp_path"),
@@ -369,7 +376,8 @@ static ngx_str_t ngx_http_scgi_hide_head
#if (NGX_HTTP_CACHE)

static ngx_keyval_t ngx_http_scgi_cache_headers[] = {
- { ngx_string("HTTP_IF_MODIFIED_SINCE"), ngx_string("") },
+ { ngx_string("HTTP_IF_MODIFIED_SINCE"),
+ ngx_string("$upstream_cache_last_modified") },
{ ngx_string("HTTP_IF_UNMODIFIED_SINCE"), ngx_string("") },
{ ngx_string("HTTP_IF_NONE_MATCH"), ngx_string("") },
{ ngx_string("HTTP_IF_MATCH"), ngx_string("") },
@@ -1093,6 +1101,7 @@ ngx_http_scgi_create_loc_conf(ngx_conf_t
conf->upstream.cache_valid = NGX_CONF_UNSET_PTR;
conf->upstream.cache_lock = NGX_CONF_UNSET;
conf->upstream.cache_lock_timeout = NGX_CONF_UNSET_MSEC;
+ conf->upstream.cache_revalidate = NGX_CONF_UNSET;
#endif

conf->upstream.hide_headers = NGX_CONF_UNSET_PTR;
@@ -1333,6 +1342,9 @@ ngx_http_scgi_merge_loc_conf(ngx_conf_t
ngx_conf_merge_msec_value(conf->upstream.cache_lock_timeout,
prev->upstream.cache_lock_timeout, 5000);

+ ngx_conf_merge_value(conf->upstream.cache_revalidate,
+ prev->upstream.cache_revalidate, 0);
+
#endif

ngx_conf_merge_value(conf->upstream.pass_request_headers,
diff --git a/src/http/modules/ngx_http_uwsgi_module.c b/src/http/modules/ngx_http_uwsgi_module.c
--- a/src/http/modules/ngx_http_uwsgi_module.c
+++ b/src/http/modules/ngx_http_uwsgi_module.c
@@ -289,6 +289,13 @@ static ngx_command_t ngx_http_uwsgi_comm
offsetof(ngx_http_uwsgi_loc_conf_t, upstream.cache_lock_timeout),
NULL },

+ { ngx_string("uwsgi_cache_revalidate"),
+ NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
+ ngx_conf_set_flag_slot,
+ NGX_HTTP_LOC_CONF_OFFSET,
+ offsetof(ngx_http_uwsgi_loc_conf_t, upstream.cache_revalidate),
+ NULL },
+
#endif

{ ngx_string("uwsgi_temp_path"),
@@ -402,7 +409,8 @@ static ngx_str_t ngx_http_uwsgi_hide_hea
#if (NGX_HTTP_CACHE)

static ngx_keyval_t ngx_http_uwsgi_cache_headers[] = {
- { ngx_string("HTTP_IF_MODIFIED_SINCE"), ngx_string("") },
+ { ngx_string("HTTP_IF_MODIFIED_SINCE"),
+ ngx_string("$upstream_cache_last_modified") },
{ ngx_string("HTTP_IF_UNMODIFIED_SINCE"), ngx_string("") },
{ ngx_string("HTTP_IF_NONE_MATCH"), ngx_string("") },
{ ngx_string("HTTP_IF_MATCH"), ngx_string("") },
@@ -1130,6 +1138,7 @@ ngx_http_uwsgi_create_loc_conf(ngx_conf_
conf->upstream.cache_valid = NGX_CONF_UNSET_PTR;
conf->upstream.cache_lock = NGX_CONF_UNSET;
conf->upstream.cache_lock_timeout = NGX_CONF_UNSET_MSEC;
+ conf->upstream.cache_revalidate = NGX_CONF_UNSET;
#endif

conf->upstream.hide_headers = NGX_CONF_UNSET_PTR;
@@ -1370,6 +1379,9 @@ ngx_http_uwsgi_merge_loc_conf(ngx_conf_t
ngx_conf_merge_msec_value(conf->upstream.cache_lock_timeout,
prev->upstream.cache_lock_timeout, 5000);

+ ngx_conf_merge_value(conf->upstream.cache_revalidate,
+ prev->upstream.cache_revalidate, 0);
+
#endif

ngx_conf_merge_value(conf->upstream.pass_request_headers,
diff --git a/src/http/ngx_http_cache.h b/src/http/ngx_http_cache.h
--- a/src/http/ngx_http_cache.h
+++ b/src/http/ngx_http_cache.h
@@ -19,8 +19,9 @@
#define NGX_HTTP_CACHE_EXPIRED 3
#define NGX_HTTP_CACHE_STALE 4
#define NGX_HTTP_CACHE_UPDATING 5
-#define NGX_HTTP_CACHE_HIT 6
-#define NGX_HTTP_CACHE_SCARCE 7
+#define NGX_HTTP_CACHE_REVALIDATED 6
+#define NGX_HTTP_CACHE_HIT 7
+#define NGX_HTTP_CACHE_SCARCE 8

#define NGX_HTTP_CACHE_KEY_LEN 16

@@ -143,6 +144,7 @@ void ngx_http_file_cache_create_key(ngx_
ngx_int_t ngx_http_file_cache_open(ngx_http_request_t *r);
void ngx_http_file_cache_set_header(ngx_http_request_t *r, u_char *buf);
void ngx_http_file_cache_update(ngx_http_request_t *r, ngx_temp_file_t *tf);
+void ngx_http_file_cache_update_header(ngx_http_request_t *r);
ngx_int_t ngx_http_cache_send(ngx_http_request_t *);
void ngx_http_file_cache_free(ngx_http_cache_t *c, ngx_temp_file_t *tf);
time_t ngx_http_file_cache_valid(ngx_array_t *cache_valid, ngx_uint_t status);
diff --git a/src/http/ngx_http_file_cache.c b/src/http/ngx_http_file_cache.c
--- a/src/http/ngx_http_file_cache.c
+++ b/src/http/ngx_http_file_cache.c
@@ -53,6 +53,7 @@ ngx_str_t ngx_http_cache_status[] = {
ngx_string("EXPIRED"),
ngx_string("STALE"),
ngx_string("UPDATING"),
+ ngx_string("REVALIDATED"),
ngx_string("HIT")
};

@@ -971,6 +972,116 @@ ngx_http_file_cache_update(ngx_http_requ
}


+void
+ngx_http_file_cache_update_header(ngx_http_request_t *r)
+{
+ ssize_t n;
+ ngx_err_t err;
+ ngx_file_t file;
+ ngx_file_info_t fi;
+ ngx_http_cache_t *c;
+ ngx_http_file_cache_header_t h;
+
+ ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+ "http file cache update header");
+
+ c = r->cache;
+
+ ngx_memzero(&file, sizeof(ngx_file_t));
+
+ file.name = c->file.name;
+ file.log = r->connection->log;
+ file.fd = ngx_open_file(file.name.data, NGX_FILE_RDWR, NGX_FILE_OPEN, 0);
+
+ if (file.fd == NGX_INVALID_FILE) {
+ err = ngx_errno;
+
+ /* cache file may have been deleted */
+
+ if (err == NGX_ENOENT) {
+ ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+ "http file cache \"%s\" not found",
+ file.name.data);
+ return;
+ }
+
+ ngx_log_error(NGX_LOG_CRIT, r->connection->log, err,
+ ngx_open_file_n " \"%s\" failed", file.name.data);
+ return;
+ }
+
+ /*
+ * make sure cache file wasn't replaced;
+ * if it was, do nothing
+ */
+
+ if (ngx_fd_info(file.fd, &fi) == NGX_FILE_ERROR) {
+ ngx_log_error(NGX_LOG_CRIT, r->connection->log, ngx_errno,
+ ngx_fd_info_n " \"%s\" failed", file.name.data);
+ goto done;
+ }
+
+ if (c->uniq != ngx_file_uniq(&fi)
+ || c->length != ngx_file_size(&fi))
+ {
+ ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+ "http file cache \"%s\" changed",
+ file.name.data);
+ goto done;
+ }
+
+ n = ngx_read_file(&file, (u_char *) &h,
+ sizeof(ngx_http_file_cache_header_t), 0);
+
+ if (n == NGX_ERROR) {
+ goto done;
+ }
+
+ if ((size_t) n != sizeof(ngx_http_file_cache_header_t)) {
+ ngx_log_error(NGX_LOG_CRIT, r->connection->log, 0,
+ ngx_read_file_n " read only %z of %z from \"%s\"",
+ n, sizeof(ngx_http_file_cache_header_t), file.name.data);
+ goto done;
+ }
+
+ if (h.last_modified != c->last_modified
+ || h.crc32 != c->crc32
+ || h.header_start != c->header_start
+ || h.body_start != c->body_start)
+ {
+ ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+ "http file cache \"%s\" content changed",
+ file.name.data);
+ goto done;
+ }

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