Common parameters consist of common request parameters and common response parameters.

Common request parameters

The following table describes common request parameters that can be used when you call Elastic Compute Service (ECS) API operations by sending GET requests over URLs.

Parameter Type Required Description
Action String Yes The operation that you want to perform. For more information about the parameter values, see List of operations by function.
AccessKeyId String Yes The AccessKey ID provided to you by Alibaba Cloud. AccessKey pairs are used to call API operations. Usernames and passwords are used to log on to the ECS console. For more information, see Create an AccessKey pair.
Signature String Yes The signature string of the request. For information about how signatures are calculated, see Request signatures.
SignatureMethod String Yes The encryption method of the signature string. Set the value to HMAC-SHA1.
SignatureVersion String Yes The version of the signature encryption algorithm. Set the value to 1.0.
SignatureNonce String Yes A unique, random number used to prevent replay attacks. You must use different numbers for different requests.
Timestamp String Yes The timestamp of the request. Specify the time in the ISO 8601 standard in the yyyy-MM-ddTHH:mm:ssZ format. The time must be in UTC. Example: 2018-01-01T12:00:00Z, which indicates 20:00:00 on January 1, 2018 (UTC+8).
Version String Yes The version number of the API. The value must be in the YYYY-MM-DD format. Set the value to 2014-05-26.
Format String No The format of the response parameters. Valid values:
  • json
  • xml
Default value: xml.

Sample requests

Note The following content provides only sample values. Perform URL encoding in your actual operations. For more information, see the "Step 1: Create a canonicalized query string" section in Request signatures.<API Name>

Common response parameters

Parameter Type Description
RequestId String The ID of the request. This parameter is returned regardless of whether the operation is successful.