Making an API Request

Updated on 2025-04-25 GMT+08:00

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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 passing the request URI 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. The endpoint varies between services in different regions. It can be obtained from Regions and Endpoints. For example, the endpoint of IAM in CN-Hong Kong is iam.ap-southeast-1.myhuaweicloud.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. 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 means to query up to 10 pieces of data.

https://iam.ap-southeast-3.myhuaweicloud.com/v3/auth/tokens

Figure 1 Example URI

NOTE:

To simplify the URI display, 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.

For example, to create an IAM user, obtain the endpoint of any region (for example, the endpoint of CN-Hong Kong: iam.ap-southeast-1.myhuaweicloud.com) and resource-path (/v3.0/OS-USER/users) in the URI of the API for creating an IAM user as an administrator. Then, construct the URI as follows:

https://iam.ap-southeast-1.myhuaweicloud.com/v3.0/OS-USER/users

Figure 2 Example URI

NOTE:

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 a server resource header.
PATCH: requests the server to update partial content of a specified resource. If the resource does not exist, a new resource can be created using the PATCH method.

For example, in the URI of the API for creating an IAM user as an administrator, the request method is POST. The request is as follows:

POST https://iam.ap-southeast-1.myhuaweicloud.com/v3.0/OS-USER/users

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: 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-Auth-Token: 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.
Authorization: signature authentication information. This field is optional. When AK/SK-based authentication is enabled, this field is automatically specified when SDK is used to sign the request. For details, see AK/SK-based Authentication.
X-Sdk-Date: time when a request is sent. This field is optional. When AK/SK-based authentication is enabled, this field is automatically specified when SDK is used to sign the request. For details, see AK/SK-based Authentication.
X-Project-ID: 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 subproject through AK/SK-based authentication.
X-Domain-ID: 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.

For the API for creating an IAM user as an administrator, if AK/SK-based authentication is enabled, the request with the header is as follows:

POST https://iam.ap-southeast-1.myhuaweicloud.com/v3.0/OS-USER/users
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.

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.

For the API for creating an IAM user as an administrator, you can check the required request parameters and their description in the API request. The following provides an example request with a body included. Replace the italic fields in bold with the actual values.

accountid: ID of the account to which the IAM user belongs.
username: IAM username to be created.
email: email address of the IAM user.
**********: password of the IAM user.

 
POST https://iam.ap-southeast-1.myhuaweicloud.com/v3.0/OS-USER/users 
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" 
     } 
 }