If-Modified-Since is already sent by most web browsers to httpd. This
patch adds a check to server_file_access before we send the file back.
This does not do any checks for autoindex directories as the size and
last modification dates of files would not get updated properly.
I separated the logic for checking the header values as it can be
reused for different side effects of other headers like Range.
Index: usr.sbin/httpd/server_file.c
===================================================================
RCS file: /cvs/src/usr.sbin/httpd/server_file.c,v
retrieving revision 1.51
diff -u -p -r1.51 server_file.c
--- usr.sbin/httpd/server_file.c 12 Feb 2015 10:05:29 -0000 1.51
+++ usr.sbin/httpd/server_file.c 18 Apr 2015 16:41:55 -0000
@@ -42,6 +42,7 @@ int server_file_request(struct httpd *,
struct stat *);
int server_file_index(struct httpd *, struct client *, struct stat *);
int server_file_method(struct client *);
+int server_file_modified_since(struct http_descriptor *, struct stat *);
int
server_file_access(struct httpd *env, struct client *clt,
@@ -123,6 +124,10 @@ server_file_access(struct httpd *env, st
goto fail;
}
+ if ((ret = server_file_modified_since(desc, &st)) != -1) {
+ return ret;
+ }
+
return (server_file_request(env, clt, path, &st));
fail:
@@ -466,4 +471,24 @@ server_file_error(struct bufferevent *be
}
server_close(clt, "unknown event error");
return;
+}
+
+int
+server_file_modified_since(struct http_descriptor * desc, struct stat * st)
+{
+ struct kv key, *since;
+ struct tm tm;
+
+ memset(&tm, 0, sizeof(struct tm));
+
+ key.kv_key = "If-Modified-Since";
+ if ((since = kv_find(&desc->http_headers, &key)) != NULL &&
+ since->kv_value != NULL) {
+ if (strptime(since->kv_value, "%a, %d %h %Y %T %Z", &tm) !=
NULL &&
+ timeoff(&tm, 0L) >= st->st_mtim.tv_sec) {
+ return 304;
+ }
+ }
+
+ return (-1);
}
