Data Structure

Table 1 describes common request headers.

**Table 1** Common request header fields
Parameter	Mandatory	Type	Description
X-Sdk-Date	Yes	String	Time when the request is sent. The time is in YYYYMMDD'T'HHMMSS'Z' format. The value is the current GMT time of the system.
Authorization	Yes	String	Authentication information. The value can be obtained from the request signing result. For details, see AK/SK-based Authentication.
Host	Yes	String	Server information of the resource being requested. The value can be obtained from the URL of the service API. The value is in the format of hostname:port number. If the port number is not specified, the default port is used. The default port number for HTTPS is 443.
Content-type	Yes	String	Request body MIME type.
Content-Length	No	Int	Size of the request body, measured in bytes. Mandatory for POST and PUT requests, but must be left blank for GET requests.
X-Project-Id	No	String	Project ID used to obtain a token for each project.
X-Auth-Token	No	String	User token. This parameter is mandatory for authentication using tokens.