Making an API Request

This section describes the structure of a REST API request and uses the RGC API for querying the governance policy status as an example to demonstrate how to call an API.

Request URI

A request URI is in the following format:

{URI-scheme} :// {Endpoint} / {resource-path} ? {query-string}

**Table 1** Parameter description
Parameter	Description
URI-scheme	Protocol used to transmit requests. All APIs use HTTPS.
Endpoint	Domain name or IP address of the server bearing the REST service. The endpoint varies between services in different regions. It can be obtained from Regions and Endpoints .
resource-path	Access path of an API for performing a specified operation. Obtain the path from the URI of an API. For example, the resource-path of the API for querying the governance policy status is /v1/governance/operation-control-status/{operation_control_status_id}, where operation_control_status_id represents the operation ID for enabling or disabling a governance policy.
query-string	An optional query parameter. Ensure that a question mark (?) is included before each query parameter that is in the format of Parameter name=Parameter value. For example, ?limit=10 indicates that a maximum of 10 data records will be displayed.

For example, to query the status of a governance policy enabled in the CN North-Beijing4 region, obtain the endpoint (rgc.cn-north-4.myhuaweicloud.com) for this region and the resource-path (/v1/governance/operation-control-status/{operation_control_status_id}) in the URI of the API used to query the governance policy status. Then, construct the URI as follows:

https://rgc.cn-north-4.myhuaweicloud.com/v1/governance/operation-control-status/{operation_control_status_id}

Request Methods

The HTTP protocol defines the following request methods that can be used to send a request to the server:

GET: requests the server to return specified resources.
PUT: requests the server to update specified resources.
POST: requests the server to add resources or perform special operations.
DELETE: requests the server to delete specified resources, for example, an object.
HEAD: requests the server to return only the response header.
PATCH: requests the server to update partial content of a specified resource. If the resource does not exist, a new resource will be created.

For example, in the case of the API for querying the governance policy status, the request method is GET. The request is as follows:

GET https://rgc.cn-north-4.myhuaweicloud.com/v1/governance/operation-control-status/{operation_control_status_id}

Request Header

You can also add additional header fields to a request, such as the fields required by a specified URI or HTTP method. For example, to request for the authentication information, add Content-Type, which specifies the request body type.

Common request headers are as follows:

**Table 2**
Header	Description	Mandatory
Content-Type	Request body type or format. Its default value is application/json. Other values of this field will be provided for specific APIs.	Yes
Authorization	Signature information in the request. For details about AK/SK authentication, see AK/SK-based Authentication.	Yes
Host	Host address, for example, rgc.cn-north-4.myhuaweicloud.com.	Yes
X-Sdk-Date	Date and time when the request was sent, for example, 20221107T020014Z.	Yes

APIs support authentication using access key ID/secret access key (AK/SK). During AK/SK-based authentication, an SDK is used to sign the request, and the Authorization (signature information) and X-Sdk-Date (time when the request is sent) header fields are automatically added to the request. For more information, see AK/SK-based Authentication.

For example, the request for the API in Querying the Operating Status of a Governance Policy is as follows:

GET https://rgc.cn-north-4.myhuaweicloud.com/v1/governance/operation-control-status/c0jquihv-x3ve-1lb9-qmix-dankod8dg86z
Content-Type: application/json; charset=UTF-8
X-Sdk-Date: 20240527T021902Z
Host: rgc.cn-north-4.myhuaweicloud.com
Authorization: SDK-HMAC-SHA256 Access=xxxxxxxxxxxxxxxxxxx, SignedHeaders=content-type;host;x-sdk-date, Signature=xxxxxxxxxxxxxxxxxxxx

Request Body

The body of a request is often sent in a structured format as specified in the Content-Type header field. The request body transfers content except the request header.

The request body varies between APIs. Some APIs do not require the request body, such as the APIs requested using the GET and DELETE methods.