Common parameters - ApsaraMQ for MQTT - Alibaba Cloud Documentation Center

This topic describes the parameters that are common to all API requests and responses for Message Queue for MQTT.

Common request parameters

Table 1. Parameters
Parameter	Type	Required	Description
Format	String	No	The response format. Valid values: JSON and XML. Default value: JSON.
Version	String	Yes	The version number of the API. Specify the version number in the YYYY-MM-DD format. Valid values: 2020-04-20
AccessKeyId	String	Yes	The AccessKey ID that is used to access Message Queue for MQTT.
Signature	String	Yes	The signature string of the request.
SignatureMethod	String	Yes	The encryption method of the signature string. Set the value to HMAC-SHA1
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. For example, use 2013-01-10T12:00:00Z to specify 20:00:00 on January 10, 2013 (UTC+8).
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 a unique random number for each request.
ResourceOwnerAccount	String	No	The Alibaba Cloud account to which the resource you want to access belongs.

Sample requests

http://onsmqtt.[regionId].aliyuncs.com/?Action=[ApiName]
&TimeStamp=2020-05-19T10%3A33%3A56Z
&Format=xml
&AccessKeyId=testid
&SignatureMethod=Hmac-SHA1
&SignatureNonce=NwDAxvLU6tFE0DVb
&Version=2020-04-20
&SignatureVersion=1.0
&Signature=[Signature]

Sample responses

API responses use the HTTP response format. Responses can be returned in either the JSON or XML format. You can specify the response format in the request. The default response format is XML. Every response returns a unique RequestId regardless of whether the call is successful.

A 2xx HTTP status code indicates a successful call.
A 4xx or 5xx HTTP status code indicates a failed call.

Sample success responses

Each response returns response parameters and a request ID for a successful call. In a success response, the HTTP status code is 2xx.

XML format

<?xml version="1.0" encoding="utf-8"?> 
    <!--Root node of the response-->
    <Operation name+Response>
        <!--Returned request tag-->
        <RequestId>4C467B38-3910-447D-87BC-AC049166F216</RequestId>
        <!--Returned data-->
    </Operation name+Response>

JSON format

{
    "RequestId":"4C467B38-3910-447D-87BC-AC049166F216",
    /*Returned data*/
    }

Sample error responses
If an error occurs when you call an operation, an error response that consists of an error code, an error message, and a request ID is returned. In an error response, the HTTP status code is 4xx or 5xx. You can troubleshoot errors based on the error codes. For more information, see Error codes. If you cannot troubleshoot errors based on the error codes, contact ApsaraMQ for MQTT technical support.
- XML format
```
<?xml version="1.0" encoding="UTF-8"?>
<Error>
    <RequestId>540CFF28-407A-40B5-B6A5-74Bxxxxxxxxx</RequestId> 
    <Code>MissingParameter.CommandId</Code> 
    <Message>The input parameter "CommandId" that is mandatory for processing this request is not supplied.</Message> 
</Error>
```
- JSON format