Making an API Request

This section describes the structure of a RESTful API request, and uses the IAM API for creating an IAM user as an example to describe 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.

Table 1 URI 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 endpoint. The endpoint varies between services in different regions. It can be obtained from Regions and Endpoints.

For example, the endpoint of IAM in the eu-de region is iam.eu-de.otc.t-systems.com.

resource-path

Access path of an API for performing a specified operation. Obtain the value from the URI of an API. For example, resource-path of the API used to create an IAM user is /v3.0/OS-USER/users.

query-string

Query parameter, which is optional. The query parameter must be in the format of parameter-name=parameter-value and prefixed with a question mark (?). For example, limit=10 indicates that a maximum of 10 data records will be displayed.

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 Methods

The HTTP protocol defines the following request methods that can be used to send a request to the server.
Table 2 HTTP methods

Method

Description

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.

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 include:

Request Body

The body of a request is often sent in a structured format (JSON or XML) as specified in the Content-type header field. The request body transfers content except the request header. If the request body contains Chinese characters, these characters must be coded in UTF-8. Specify the character encoding mode in Content-type, for example, Content-Type: application/json; charset=utf-8.

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.

In the case of the API used to , the request parameters and parameter description can be obtained from the API request. The following provides an example request with a body included.

Content-type: application/json
X-Sdk-Date: 20240416T095341Z 
 Authorization: SDK-HMAC-SHA256 Access=****************, SignedHeaders=content-type;host;x-sdk-date, Signature=**************** 
{ 
      "user": { 
          "domain_id": "accountid", 
          "name": "username", 
          "password": "**********", 
          "email": "email", 
          "description": "IAM User Description" 
      } 
  }

The content required by an API request is ready. You can use curl, Postman, or write code to send the request to call the API.

Parent topic: Calling APIs