Contents：
Description
This document describes Common Request Headers to be used when using APIs. The headers described below will not be discussed in later API documents.
List of Request Headers
| Header Name | Description | Type | Required |
|---|---|---|---|
| Authorization | Contain authentication information, signature information used to verify the validity of requests. This header is not required for files that can be read by public users. | String | No |
| Content-Length | HTTP request content length defined in RFC 2616 (bytes), commonly used in API operations of PUT type. | String | No |
| Content-Type | HTTP request content type defined in RFC 2616 (MIME), for example: text/plain | String | No |
| Content-MD5 | 128-bit content MD5 check value encoded using Base64, defined in RFC 1864. This header is used to check whether the file content has changed. | String | No |
| Date | GMT time defined in RFC 1123, for example: Wed, 30 Mar. 2016 23:00:00 GMT. | String | No |
| Expect | If Expect: 100-continue is used, the request content will not be sent until the receipt of response from server. This option can be used to check whether a header is valid, without the need to send the data content. Valid value: 100-continue. |
String | No |
| Host | Request host, in a form of |
String | Yes |
