Making an API Request

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 the AP-Singapore region is iam.ap-southeast-3.myhwcloud.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 for obtaining a user token is /v3/auth/tokens.
• 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.

For example, to obtain an IAM token in the AP-Singapore region, use the endpoint (iam.ap-southeast-3.myhuaweicloud.com) of this region, and 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

NOTE:

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

Request Method

HTTP-based request methods, which are also called operations or actions, specify the type of operations that you are requesting.

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

For example, in the case of the API for obtaining a user token, the request method is POST. 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 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. This field is mandatory The user token is a response to the API for obtaining a user token. This API is the only one that does not require authentication.

NOTE:

In addition to supporting token-based authentication, public cloud 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 AK/SK Authentication.

• X-Project-ID: subproject ID. This field is optional and can be used in multi-project scenarios.
• X-Domain-ID: account ID.

The API for obtaining a user token does not require authentication. Therefore, only the Content-Type field needs to be added to request headers 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

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

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

In the case of 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 name, for example, (ap-southeast-3)) with the actual values. Obtain a project name from Regions and Endpoints.

NOTE:

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 more information about this API, see Obtaining a User Token

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": "xxxxxxxxxxxxxxxxxx" 
            } 
        } 
    } 
}

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 for obtaining a user token, x-subject-token is the desired user token. This token can then be used to authenticate the calling of other APIs.