Making an API Request

Request URI

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

A request URI consists of four parts: {URI-scheme} :// {Endpoint} / {resource-path}? {query-string}

For example, to obtain the IAM token in the AP-Singapore region , obtain the endpoint of this region (iam.ap-southeast-3.myhuaweicloud.com) and find the resource-path (/v3/auth/tokens) in the URI of the API for obtaining a user token. Then, construct the URI as follows:

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

Figure 1 Example URI

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

Request Methods

HTTP 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, such as 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, when you call the API to obtain a user token, the request method is POST, and the request is as follows:

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

Request Header

You can also add additional header fields to a request, such as fields for specifying a URI and an HTTP method. For example, to request 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-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.
  

  In addition to supporting token-based authentication, APIs also 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 Authentication.

• X-Project-ID: specifies a subproject ID. This parameter is optional. It is used in multi-project scenarios.
• X-Domain-ID: identifies an account.

The API used to obtain a user token does not require authentication. Therefore, only the Content-Type field needs to be added to requests for calling the API. An example of such requests is as follows:

POST https://iam.ap-southeast-3.myhuaweicloud.com/v3/auth/tokens
Content-Type: application/json

Request Body

A request body is often sent in structured format. It corresponds to Content-Type in the request header and passes content except the request header.

The request body varies according to APIs. Certain APIs do not require the request body, such as GET and DELETE.

When you call the API for obtaining a user token, the request parameters and parameter description can be obtained from the API request. The following provides an example request with a body included. Replace username, domainname, ******** (login password), and xxxxxxxxxx (project ID, for example, ap-southeast-3) with the actual values. The project ID can be obtained from Endpoints.

The scope parameter specifies where a token takes effect. You can set scope to an account or a project under an account. In the following example, the token takes effect only for the resources in a specified project. For details about this API, see Obtaining a User Token Through Password Authentication.

POST https://iam.ap-southeast-3.myhuaweicloud.com/v3/auth/tokens
Content-Type: application/json

{
    "auth": {
        "identity": {
            "methods": [
                "password"
            ],
            "password": {
                "user": {
                    "name": "username",
                    "password": "********",
                    "domain": {
                        "name": "domainname"
                    }
                }
            }
        },
        "scope": {
            "project": {
                "name": "xxxxxxxx"
            }
        }
    }
}

If all data required for the API request is available, you can send the request to call the API through curl, Postman, or coding. In the response to the API used to obtain a user token, x-subject-token is the desired user token. This token can then be used to authenticate requests for calling other APIs.