Help Center/ API Gateway/ API Reference (Kuala Lumpur Region)/ Calling APIs/ Making an API Request
Updated on 2024-08-06 GMT+08:00
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Making an API Request

This section describes the structure of a REST API request, and uses the APIG API for creating an API group 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}

Although a request URI is included in the request header, most programming languages or frameworks require the request URI to be transmitted separately.

  • URI-scheme: Protocol used to transmit requests. All APIs use HTTPS.
  • Endpoint: Domain name or IP address of the server bearing the REST service. It can be obtained from 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 used to create an API group is /v2/{project_id}/apigw/instances/{instance_id}/api-groups. {project_id} indicates a project ID and {instance_id} indicates a gateway ID. The two IDs can be obtained from the gateway information on the APIG console.
  • query-string: Query parameter, which is optional. Ensure that a question mark (?) is included in front of 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 queried.

For example, if you want to create an API group in a region, set URI-scheme to HTTPS, Endpoint to apig_endpoint, and resource-path to /v2/{project_id}/apigw/instances/{instance_id}/api-groups. Combine the parameters in the URI.

https://{apig_endpoint}/v2/{project_id}/apigw/instances/{instance_id}/api-groups

To simplify the URI display in this document, each API is provided only with a resource-path and a request method. The URI-scheme of all APIs is HTTPS, and the endpoints of all APIs in the same region are identical.

Request Method

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: same as GET except that the server must 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 used to create an API group, the request method is POST. The request is as follows:

POST https://{apig_endpoint}/v2/{project_id}/apigw/instances/{instance_id}/api-groups

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 header fields are as follows:
  • Content-Type: specifies the request body type or format. This field is mandatory and its default value is application/json. Other values of this field will be provided for specific APIs if any.
  • X-Sdk-Date: specifies the time when a request is sent. This field is optional. When AK/SK authentication is enabled, this field is automatically specified when SDK is used to sign the request. For more information, see AK/SK-based Authentication.
  • Authorization: specifies signature authentication information. This field is optional. When AK/SK authentication is enabled, this field is automatically specified when SDK is used to sign the request. For more information, see AK/SK-based Authentication.
  • X-Auth-Token: specifies a user token only for token-based API authentication. The user token is a response to the API used to obtain a user token. This API is the only one that does not require authentication.
  • X-Project-ID: specifies subproject ID. This field is optional and can be used in multi-project scenarios. The X-Project-ID field is mandatory in the request header for accessing resources in a sub-project through AK/SK-based authentication.
  • X-Domain-ID: specifies account ID, which is optional. When you call APIs of global services using AK/SK-based authentication, X-Domain-ID needs to be configured in the request header.
If AK/SK authentication is used, the requests of the API used to create an API group with the added headers are as follows: 
POST https://{apig_endpoint}/v2/{project_id}/apigw/instances/{instance_id}/api-groups
Content-Type: application/json
X-Sdk-Date: 20240416T095341Z 
Authorization: SDK-HMAC-SHA256 Access=****************, SignedHeaders=content-type;host;x-sdk-date, Signature=****************

Request Body

The body of a request is often sent in a structured format as specified in Content-Type. The request body transfers content other than the request header. If the request body contains Chinese characters, set Content-type to utf-8, for example, Content-Type: application/json; charset=utf-8.

Request bodies vary between APIs. Some APIs do not require the request body, such as the APIs requested using the GET and DELETE methods.

For the API used to create an API group, you can obtain the request parameters and parameter description from the API request. Here is an example request that includes a body. The bold fields must be configured as required.

  • name: API group name
  • remark: API group description
POST https://{apig_endpoint}/v2/{project_id}/v2/{project_id}/apigw/instances/{instance_id}/api-groups
Content-Type: application/json
X-Sdk-Date: 20240416T095341Z 
Authorization: SDK-HMAC-SHA256 Access=****************, SignedHeaders=content-type;host;x-sdk-date, Signature=****************
{
	"name": "APIGroup_test",
	"remark": "api group remark"
}

If all data required for the API request is available, you can send the request to call the API through curl, Postman, or coding.

Parent topic: Calling APIs