Making an API Request
This section describes the structure of a RESTful API request, and uses the IAM API for 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}
Parameter |
Description |
---|---|
URI-scheme |
Protocol used to transmit requests. All APIs use HTTPS. |
Endpoint |
Domain name or IP address of the server running the REST service. The endpoint varies between services in different regions. It can be obtained from Regions and Endpoints. |
resource-path |
API access path for performing a specified operation. Obtain the value from the URI of an API. . |
query-string |
Query parameter, which is optional. Ensure that a question mark (?) is included before a query parameter that is in the format of "Parameter name=Parameter value". For example, limit=10 indicates that a maximum of 10 pieces of data is to be viewed. |

To simplify the URI display, each API is provided with only 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
HTTP-based request methods, which are also called operations or actions, specify the type of operations that you are requesting.
- 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 target resource does not exist, PATCH may create a resource.
For example, in the URI of the API for , the request method is POST. The request is as follows:
Request Header
You can also add additional fields to a request, such as the fields required by a specified URI or an HTTP method. For example, add Content-Type that defines a request body type to request for the authentication information.
Table 2 lists common request header fields.
Parameter |
Mandatory |
Description |
---|---|---|
Content-Type |
Yes |
Message body type (or format). You are advised to use the default value application/json. |
X-Auth-Token |
Mandatory for token authentication |
User token. It is the response to the API for obtaining a user token (only this API does not require authentication). After the request is processed, the value of X-Subject-Token in the response header (Header) is the token value. |
X-Project-Id |
No |
Subproject ID, which is 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-Sdk-Date |
Mandatory for AK/SK authentication |
Request sending time. When AK/SK authentication is enabled, this field is automatically specified when SDK is used to sign the request. For details, see Authentication. The format is YYYYMMDD'T'HHMMSS'Z'. The value is the current GMT time of the system. |
Authorization |
Mandatory for AK/SK authentication |
Signature authentication information, When AK/SK authentication is enabled, this field is automatically specified when SDK is used to sign the request. For details, see Authentication. |
X-Language |
No |
Request language |
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