DefaultCookieJar 处理 Set-Cookie 时行为不标准

[sunnysab]

根据 RFC6265 4.1.2.4，当服务端 Set-Cookie 字段缺失 Path 时，应该使用当前页面的“目录”作为默认的 cookie 路径。也就是说，如果 URI 为 /w/login，那么 Cookie 的路径应该为 /w/。

According to RFC6265 4.1.2.4, user agent uses the "directory" of request-uri as default path if there is no 'Path' component in Set-Cookie line. In that way, if the URI is /w/login，the path of cookie will be /w/ by default.

但是在 cookie_jar 3.0.1 版本中，default_cookie_jar.dart 文件的 saveFromResponse 函数：

But in version 3.0.1 of cookie_jar, in method saveFromResponse, default_cookie_jar.dart.

@override
Future<void> saveFromResponse(Uri uri, List<Cookie> cookies) async {
  for (final cookie in cookies) {
    var domain = cookie.domain;
    String path;
    var index = 0;
    // Save cookies with "domain" attribute
    if (domain != null) {
      if (domain.startsWith('.')) {
        domain = domain.substring(1);
      }
      path = cookie.path ?? '/';
    } else {
      index = 1;
      // Save cookies without "domain" attribute
      // 注意，问题出在这里. NOTICE HERE.
      path = cookie.path ?? (uri.path.isEmpty ? '/' : uri.path);
      domain = uri.host;
    }
    var mapDomain =
        _cookies[index][domain] ?? <String, Map<String, dynamic>>{};
    mapDomain = mapDomain.cast<String, Map<String, dynamic>>();

    final map = mapDomain[path] ?? <String, dynamic>{};
    map[cookie.name] = SerializableCookie(cookie);
    if (_isExpired(map[cookie.name])) {
      map.remove(cookie.name);
    }
    mapDomain[path] = map.cast<String, SerializableCookie>();
    _cookies[index][domain] =
        mapDomain.cast<String, Map<String, SerializableCookie>>();
  }
}

默认使用了 uri.path，和预期及浏览器行为不一致。这导致了我的爬虫出了点问题……

The method uses uri.path which does in a different way with browsers. So my crawler crashed...