在Angular中使用http restful api中验证的问题

Question

代码如下:

            all: function() {
                var date = new Date(),
                    dateStr = date.toUTCString(),
                    signature = ["GET", "/alizpics/", date.toUTCString(), 0, md5("aliz****")].join("&");
                return $http({
                    method: "GET",
                    url: 'http://v0.api.upyun.com/alizpics/',
                    headers: {
                        "Host": "v0.api.upyun.com",
                        "Date": dateStr,
                        "Authorization": " UpYun alichen:" + signature
                    }
                });
            }

在chrome中调试始终显示提示Need Date Header