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Common parameters

Last Updated: Oct 20, 2017

Common request parameters

Common request parameters refer to the request parameters that every interface must use.

Parameter list

Name Type Required? Description
Format String No The type of the returned value. JSON and XML are supported, and XML is the default type.
Version String Yes API version number. The format is YYYY-MM-DD. The current version corresponds to 4/8/2016.
AccessKeyId String Yes AccessKey ID used to access services, issued to a user by Alibaba Cloud.
Signature String Yes The signature result string. Refer to the description of the signature mechanism for details on the signature calculation method.
SignatureMethod String Yes Signature method. Currently, HMAC-SHA1 is supported.
Timestamp String Yes Timestamp of a request. The date format is represented based on ISO8601, and UTC time is used. Format: YYYY-MM-DDThh:mm:ssZ, for example, 2013-08-15T12:00:00Z (20:00:00, August 15, 2013, Beijing time).
SignatureVersion String Yes Signature algorithm version. The current version is 1.0.
SignatureNonce String Yes Unique random number, used to prevent replay attacks. The user must use different random numbers for different requests.


  1. https://emr.aliyuncs.com/
  2. ?Format=json
  3. &Version=2016-04-08
  4. &Signature=Pc5WB8gokVn0xfeu%2FZV%2BiNM1dgI%3D
  5. &SignatureMethod=HMAC-SHA1
  6. &SignatureNonce=15215528852396
  7. &SignatureVersion=1.0
  8. &AccessKeyId=key-test
  9. &OwnerId=12345678
  10. &Timestamp=2014-10-10T12:00:00Z

Common return parameters

Each time the user sends a call request, whether it is successful or not, the system will return a unique identification code (RequestId) to the user.


  • Successful results

    XML returned results include a message stating if the request is successful and the specific service data. Example:

    1. {
    2. "RequestId": "4C467B38-3910-447D-87BC-AC049166F216",
    3. /* Return result data*/
    4. }
  • Error results

    When an error occurs in an interface call, no result data is returned. The caller can refer to the table in the appendix - Error Code Table to locate the cause of the error. When an error occurs in a call, the HTTP request will return an HTTP status code of 4xx or 5xx. The returned message body contains the specific error code and error information. The message body also contains the globally unique “RequestId” and the requested “HostId”. If failing to find the cause of the error, the caller can contact Alibaba Cloud customer service and provide the HostId and RequestId to help us solve the problem as quickly as possible.

    1. {
    2. "RequestId": "7463B73D-35CC-4D19-A010-6B8D65D242EF",
    3. "HostId": "emr.aliyuncs.com",
    4. "Code": "UnsupportedOperation",
    5. "Message": "The specified action is not supported."
    6. }

    Public error code

    Refer to ECS Public Error Code.

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