The following common request parameters must be added each time calling an API, and a request ID will be returned no matter the request is successful or not.

Common request parameters

Public request parameters are request parameter that each interface uses.

Table 1. Common request parameters
Name Type Required Description
Format String No The format of the response. Valid values:

JSON(default value) | XML

Version String The version of the API in the format of YYYY-MM-DD. Valid value:

2017-09-12

AccessKeyId String Yes The AccessKey ID of the user who calls the API.
Signature String Yes The request signature.
SignatureMethod String Yes The algorithm used to create the request signature. Valid value:

HMAC-SHA1

Timestamp String Yes Request timestamp. The date format follows the ISO8601 standard and uses UTC time. The format is YYYY-MM-DDThh:mm:ssZ.

Example: 2014-11-11T12:00:00Z (November 11, 2014 at 20:00:00, Beijing time)

SignatureVersion String Yes The signature version to use. Valid value:

1.0

SignatureNonce String Yes A random number for the signature to prevent from network attacks.

Different random numbers must be used for different requests.

Example
https://cbn.aliyuncs.com/?Action=DescribeCens
&TimeStamp=2014-05-19T10%3A33%3A56Z
&Format=xml
&AccessKeyId=testid
&Action=DescribeCens
&SignatureMethod=Hmac-SHA1
&CenId=CenID
&SignatureNonce=NwDAxvLU6tFE0DVb
&Version=2016-04-28
&SignatureVersion=1.0
&Signature=Signature

Common response parameters

After the API service is called, the returned data adopts a uniform format. A returned HTTP status code of 2xx indicates that the call was successful. A returned HTTP status code of 4xx or 5xx indicates that the call fails. For a successful call, the primary formats of returned data are XML and JSON. When a request is sent, an external system can input parameters to specify the format of returned data. The default format is JSON.

Each time you send a request to call an interface, the system returns a unique identification code ( RequestId), whether the request is successful.