diff src/http/ngx_http_file_cache.c @ 5878:2c89956b6a76

Cache: hash of Vary headers now stored in cache. To cache responses with Vary, we now calculate hash of headers listed in Vary, and return the response from cache only if new request headers match. As of now, only one variant of the same resource can be stored in cache.
author Maxim Dounin <mdounin@mdounin.ru>
date Mon, 27 Oct 2014 21:13:58 +0300
parents 063f7e75f9ef
children c525c0454aa5
line wrap: on
line diff
--- a/src/http/ngx_http_file_cache.c
+++ b/src/http/ngx_http_file_cache.c
@@ -29,6 +29,10 @@ static ngx_http_file_cache_node_t *
     ngx_http_file_cache_lookup(ngx_http_file_cache_t *cache, u_char *key);
 static void ngx_http_file_cache_rbtree_insert_value(ngx_rbtree_node_t *temp,
     ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel);
+static void ngx_http_file_cache_vary(ngx_http_request_t *r, u_char *vary,
+    size_t len, u_char *hash);
+static void ngx_http_file_cache_vary_header(ngx_http_request_t *r,
+    ngx_md5_t *md5, ngx_str_t *name);
 static void ngx_http_file_cache_cleanup(void *data);
 static time_t ngx_http_file_cache_forced_expire(ngx_http_file_cache_t *cache);
 static time_t ngx_http_file_cache_expire(ngx_http_file_cache_t *cache);
@@ -519,6 +523,23 @@ ngx_http_file_cache_read(ngx_http_reques
         return NGX_DECLINED;
     }
 
+    if (h->vary_len > NGX_HTTP_CACHE_VARY_LEN) {
+        ngx_log_error(NGX_LOG_CRIT, r->connection->log, 0,
+                      "cache file \"%s\" has incorrect vary length",
+                      c->file.name.data);
+        return NGX_DECLINED;
+    }
+
+    if (h->vary_len) {
+        ngx_http_file_cache_vary(r, h->vary, h->vary_len, c->variant);
+
+        if (ngx_memcmp(c->variant, h->variant, NGX_HTTP_CACHE_KEY_LEN) != 0) {
+            ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                           "http file cache vary mismatch");
+            return NGX_DECLINED;
+        }
+    }
+
     c->buf->last += n;
 
     c->valid_sec = h->valid_sec;
@@ -870,6 +891,94 @@ ngx_http_file_cache_rbtree_insert_value(
 }
 
 
+static void
+ngx_http_file_cache_vary(ngx_http_request_t *r, u_char *vary, size_t len,
+    u_char *hash)
+{
+    u_char     *p, *last;
+    ngx_str_t   name;
+    ngx_md5_t   md5;
+    u_char      buf[NGX_HTTP_CACHE_VARY_LEN];
+
+    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "http file cache vary: \"%*s\"", len, vary);
+
+    ngx_md5_init(&md5);
+
+    ngx_strlow(buf, vary, len);
+
+    p = buf;
+    last = buf + len;
+
+    while (p < last) {
+
+        while (p < last && (*p == ' ' || *p == ',')) { p++; }
+
+        name.data = p;
+
+        while (p < last && *p != ',' && *p != ' ') { p++; }
+
+        name.len = p - name.data;
+
+        if (name.len == 0) {
+            break;
+        }
+
+        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "http file cache vary: %V", &name);
+
+        ngx_md5_update(&md5, name.data, name.len);
+        ngx_md5_update(&md5, (u_char *) ":", sizeof(":") - 1);
+
+        ngx_http_file_cache_vary_header(r, &md5, &name);
+
+        ngx_md5_update(&md5, (u_char *) CRLF, sizeof(CRLF) - 1);
+    }
+
+    ngx_md5_final(hash, &md5);
+}
+
+
+static void
+ngx_http_file_cache_vary_header(ngx_http_request_t *r, ngx_md5_t *md5,
+    ngx_str_t *name)
+{
+    ngx_uint_t        i;
+    ngx_list_part_t  *part;
+    ngx_table_elt_t  *header;
+
+    part = &r->headers_in.headers.part;
+    header = part->elts;
+
+    for (i = 0; /* void */ ; i++) {
+
+        if (i >= part->nelts) {
+            if (part->next == NULL) {
+                break;
+            }
+
+            part = part->next;
+            header = part->elts;
+            i = 0;
+        }
+
+        if (header[i].hash == 0) {
+            continue;
+        }
+
+        if (header[i].key.len != name->len) {
+            continue;
+        }
+
+        if (ngx_strncasecmp(header[i].key.data, name->data, name->len) != 0) {
+            continue;
+        }
+
+        ngx_md5_update(md5, header[i].value.data, header[i].value.len);
+    }
+}
+
+
 void
 ngx_http_file_cache_set_header(ngx_http_request_t *r, u_char *buf)
 {
@@ -901,6 +1010,19 @@ ngx_http_file_cache_set_header(ngx_http_
         ngx_memcpy(h->etag, c->etag.data, c->etag.len);
     }
 
+    if (c->vary.len) {
+        if (c->vary.len > NGX_HTTP_CACHE_VARY_LEN) {
+            /* should not happen */
+            c->vary.len = NGX_HTTP_CACHE_VARY_LEN;
+        }
+
+        h->vary_len = (u_char) c->vary.len;
+        ngx_memcpy(h->vary, c->vary.data, c->vary.len);
+
+        ngx_http_file_cache_vary(r, c->vary.data, c->vary.len, c->variant);
+        ngx_memcpy(h->variant, c->variant, NGX_HTTP_CACHE_KEY_LEN);
+    }
+
     p = buf + sizeof(ngx_http_file_cache_header_t);
 
     p = ngx_cpymem(p, ngx_http_file_cache_key, sizeof(ngx_http_file_cache_key));
@@ -1093,6 +1215,19 @@ ngx_http_file_cache_update_header(ngx_ht
         ngx_memcpy(h.etag, c->etag.data, c->etag.len);
     }
 
+    if (c->vary.len) {
+        if (c->vary.len > NGX_HTTP_CACHE_VARY_LEN) {
+            /* should not happen */
+            c->vary.len = NGX_HTTP_CACHE_VARY_LEN;
+        }
+
+        h.vary_len = (u_char) c->vary.len;
+        ngx_memcpy(h.vary, c->vary.data, c->vary.len);
+
+        ngx_http_file_cache_vary(r, c->vary.data, c->vary.len, c->variant);
+        ngx_memcpy(h.variant, c->variant, NGX_HTTP_CACHE_KEY_LEN);
+    }
+
     (void) ngx_write_file(&file, (u_char *) &h,
                           sizeof(ngx_http_file_cache_header_t), 0);