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.
Request URI
The format of a request URI is as follows:
{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 for the REST service endpoint. The endpoint varies depending on services in different regions. It can be obtained in Endpoint. For example, the endpoint of IAM in the CN-Hong Kong region is iam.ap-southeast-1.myhuaweicloud.com. |
|
resource-path |
Access path of an API for performing a specified operation. 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. |
For example, to obtain a token in the CN-Hong Kong region, obtain the endpoint of IAM (iam.ap-southeast-1.myhuaweicloud.com) for this region and the resource-path (/v3/auth/tokens) in the URI of the API used to obtain a user token. Then, construct the URI as follows:
https://iam.ap-southeast-1.myhuaweicloud.com/v3/auth/tokens
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:
|
Method |
Description |
|---|---|
|
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. |
POST https://iam.ap-southeast-1.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.
Tabla 3 describes the common request header fields to be added to the request.
|
Header |
Description |
Mandatory |
Example |
|---|---|---|---|
|
Content-type |
Request body type or format. The default value is application/json. |
Yes |
application/json |
|
Content-Length |
Length of the request body. The unit is byte. |
Mandatory for POST and PUT requests but must be left blank for GET requests |
3495 |
|
X-Project-Id |
Project ID. This parameter is used to obtain the token for each project. |
No |
e9993fc787d94b6c886cbaa340f9c0f4 |
|
X-Auth-Token |
User token. It is a response to the API used to obtain a user token. This API is the only one that does not require authentication. |
Mandatory for token-based authentication |
None |
|
X-Sdk-Date |
Time when the request is sent. The time is in YYYYMMDD'T'HHMMSS'Z' format. The value is the current Greenwich Mean Time (GMT) time of the system. |
Mandatory for AK/SK-based authentication, optional for PKI token-based authentication |
20190307T101459Z |
|
Authorization |
Authentication information. The value is obtained from the request signature result and is required when the AK/SK are used to encrypt the signature. Type: string Default value: none |
Mandatory for AK/SK-based authentication |
SDK-HMAC-SHA256 Credential=ZIRRKMTWPTQFQI1WKNKB/20150907//ec2/sdk_request, SignedHeaders=content-type;host;x-sdk-date, Signature=55741b610f3c9fa3ae40b5a8021ebf7ebc2a28a603fc62d25cb3bfe6608e1994 |
|
Host |
Information about the requested server. The value can be obtained from the URL of the service API. This value is host name[:port number]. If the port number is not specified, the default port is used. The default port number for https is 443. |
Mandatory for AK/SK-based authentication |
code.test.com or code.test.com:443 |
In addition to supporting authentication using tokens, APIs support authentication using AK/SK, which uses SDK to sign a request. During the signature, the Authorization (signature authentication) and X-Sdk-Date (time when a request is sent) headers are automatically added to the request. For details about AK/SK authentication, see API Request Signing Guide.
POST https://iam.ap-southeast-1.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 the Content-Type header field. The request body transfers content except the request header. If the request body contains Chinese characters, these characters must be encoded in 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.
If an API is 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 user_name, domain_name, and user_password with the actual username, account name, and login password, respectively. ap-southeast-1 is the project name. For details, see Obtaining a Username, Obtención de un nombre de cuenta y su ID, and Obtaining a Project Name.
The scope parameter specifies where a token takes effect. In the example, the token takes effect only for the resources in a specified project. ModelArts uses a region-specific endpoint to call this API. Set scope to project. 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-1.myhuaweicloud.com/v3/auth/tokens
Content-Type:application/json
{
"auth": {
"identity": {
"methods": ["password"],
"password": {
"user": {
"name": "Username",
"password": "User password",
"domain": {
"name": "Domain name"
}
}
}
},
"scope": {
"project": {
"name": "ap-southeast-1"
}
}
}
}
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 the calling of other APIs.
