Making an API Request
This section describes the structure of a REST API request, and uses the IAM API for obtaining a user token as an example to demonstrate how to call an API. The obtained token can then be used to authenticate the calling of other APIs.
Representational State Transfer (REST) allocates Uniform Resource Identifiers (URIs) to dispersed resources so that the resources can be located. Applications on clients use Unified Resource Locators (URLs) to obtain the resources.
- The URL of APIs described in Cluster Management is in the format of https://Endpoint/uri. In the URL, uri indicates the resource path, that is, the path for API access.
- The URL of Kubernetes-native APIs is in the format of https://{clusterid}.Endpoint/uri. In the URL, {clusterid} indicates a cluster ID, and uri indicates the resource path, that is, the path for API access.
Parameter | Description |
---|---|
{clusterid} | Cluster ID. After a cluster is created, the API provided in Listing Clusters in a Specified Project is called to obtain the cluster ID. |
Endpoint | URL that is the entry point for a web service. You can obtain it from Before You Start. |
uri | Resource path, that is, the API access path. Obtain the path from the URI of an API. For example, the resource-path of the API used to obtain a user token is v3/auth/tokens. |
Request URI
The request URI consists of the following parts:
{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. The endpoint varies between services in different regions. It can be obtained from Regions and Endpoints.
- resource-path
Resource path, that is, the API access path. Obtain the path from the URI of an API. For example, the resource-path of the API used to obtain 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 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:
- 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 URI for obtain a user token, the request method is POST, and the request is as follows:
POST https://iam.ru-moscow-1.hc.sbercloud.ru/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: 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.Note
In addition to supporting token-based authentication, 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-based Authentication.
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.ru-moscow-1.hc.sbercloud.ru/v3/auth/tokensContent-Type: application/json
Request Body
The body of a request is often sent in a structured format as specified in the Content-Type header field. The request body transfers content except the request header.
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 obtain 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, accountname, ******** (login password), and xxxxxxxxxxxxxxxxxx (project name) with the actual values. The project name can be obtained from Regions and 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 more information about this API, see Obtaining a User Token.
POST https://iam.ru-moscow-1.hc.sbercloud.ru/v3/auth/tokensContent-Type: application/json{"auth": {"identity": {"methods": ["password"],"password": {"user": {"name": "username","password": "********","domain": {"name": "domainname"}}}},"scope": {"project": {"name": "xxxxxxxxxxxxxxxxxx"}}}}
- Request URI
- Request Methods
- Request Header
- Request Body