Merge pull request #5 from virtion/master

added support for purging multiple pages with the same cache key

Author: torden

README.md

@@ -114,6 +114,27 @@ The asterisk must be the last character of the key, so you **must** put the $uri
 
 
 
+Purging multiple cache entries with the same cache key
+======================================================
+Caching requests that use the "Vary" header may result in multiple cache
+entries with the same cache key. For example, when using the request header
+"Vary: Accept-Encoding", a separate cache entry (with different file hash)
+will be stored for each content encoding (like compressed or uncompressed),
+but they will all have the exact same cache key.
+
+Trying to purge such cached content will fail unless both the "Vary" header
+is specified in the purge request, plus all headers as listed in the "Vary"
+header, with the exact same values as used when the request was cached.
+
+To be able to purge *all* pages with the same cache key, specify the key with
+a "$" at the end, like this:
+
+    curl -X PURGE /page$
+
+This will purge all content with the exact key "/page" from the cache.
+
+
+
 Sample configuration (same location syntax)
 ===========================================
     http {

ngx_cache_purge_module.c

@@ -1807,8 +1807,16 @@ ngx_http_cache_purge_partial(ngx_http_request_t *r, ngx_http_file_cache_t *cache
     len = key[0].len;
 
     /* Only check the first key */
-    key_partial = ngx_pcalloc(r->pool, sizeof(u_char) * len);
-    ngx_memcpy(key_partial, key[0].data, sizeof(u_char) * (len - 1));
+    if (key[0].data[key[0].len - 1] == '$') {
+        /* Check key for exact match (key terminated by newline) */
+        key_partial = ngx_pcalloc(r->pool, sizeof(u_char) * (len + 1));
+        ngx_memcpy(key_partial, key[0].data, sizeof(u_char) * (len - 1));
+        key_partial[len - 1] = '\n';
+    } else {
+        /* Check key for prefix match */
+        key_partial = ngx_pcalloc(r->pool, sizeof(u_char) * len);
+        ngx_memcpy(key_partial, key[0].data, sizeof(u_char) * (len - 1));
+    }
 
     /* Walk the tree and remove all the files matching key_partial */
     ngx_tree_ctx_t  tree;
@@ -1833,7 +1841,8 @@ ngx_http_cache_purge_is_partial(ngx_http_request_t *r) {
     key = c->keys.elts;
 
     /* Only check the first key */
-    return key[0].data[key[0].len - 1] == '*';
+    return (key[0].data[key[0].len - 1] == '*' ||
+            key[0].data[key[0].len - 1] == '$');
 }
 
 char *