Obtaining an AK/SK Pair

If an AK/SK pair is already available, skip this step. Find the downloaded AK/SK file, which is usually named credentials.csv.

As shown in the following figure, the file contains the username, AK, and SK.

Figure 1 Content of the credential.csv file

Figure 2 Obtaining an access key

Obtaining the URI

Before calling an API, you need to obtain the API URI. The procedure is as follows:

1. Log in to the ModelArts management console. In the left navigation pane, choose Service Deployment > Real-Time Services. By default, the system switches to the Real-Time Services page.
2. Click the name of the target service. The service details page is displayed.
3. Obtain the API of the service.
   Figure 3 Obtaining the API of the service
   

Preparing Environment (Python)

This section uses Python as an example to describe how to use the APIG SDK. For details about how to download and use the SDK in other languages, see the API Gateway Developer Guide.

1. Obtain the Python installation package (version 2.7.9 or 3.X) from the Python official website and install it. After Python is installed, you can run the pip install requests command to install the requests library using the Python package manager pip.
   

   If a certificate error occurs when you use pip to install the requests library, download and execute the file using Python to upgrade pip. Then run the preceding command to install the library.

2. Obtain IntelliJ IDEA from the IntelliJ IDEA official website and install it. Install the Python plug-in on IntelliJ IDEA. See Figure 4.
   Figure 4 Installing the Python plug-in
   
3. Download the ApiGateway-python-sdk.zip. The following table describes the directory structure of the decompressed package.

   Table 1 Directory structure of the decompressed package

   Name	Description
   apig_sdk\__init__.py	SDK code
   apig_sdk\signer.py
   main.py	Sample code
   backend_signature.py	Sample code for the backend signature
   licenses\license-requests	Third-party library license file

4. Create a project.
   1. Open IDEA and choose File > New > Project. On the displayed New Project page, select Python and click Next.
      Figure 5 Creating a project
      
   2. Click Next. The following page is displayed. Click ..., select the path for the decompressed SDK package, and click Finish.
      Figure 6 Selecting the SDK path after decompression
      
5. After the project is created, the directory structure is shown in the following figure. main.py is sample code. Modify the parameters to suit your requirements before use. For details about the sample code, see API Calling Example.
   Figure 7 Directory structure of a new project
   

API Calling Example

1. Add apig_sdk to the project.

   1 2	from apig_sdk import signer import requests

2. Generate a new signer and enter the AK and SK. For details about how to obtain the AK and SK, see Obtaining an AK/SK Pair.

   1 2 3

   sig = signer.Signer() sig.Key = "UATBQ1PQO1D5ORNVCDAA" sig.Secret = "ap6H7L******0QvHCNk"

3. Generate a request object and specify the method, request URI, header, and body.

   r= signer.HttpRequest(method, uri, header, body)

   Table 2 HttpRequest parameters

   Parameter	Sub-Parameter	Mandatory	Description
   method	N/A	Yes	The value can be GET, POST, PUT, or DELETE.
   uri	N/A	Yes	Enter the API URI of the real-time service. For details about how to obtain the URI, see Obtaining the URI.
   header	x-stage	Yes	API release environment, which can only be RELEASE.
   	Content-Type	No	Content type, which can only be application/json. For details about the multipart/form-data request body, see Table 3.
   	x-sdk-content-sha256	No	Signature mode. This parameter can be set to UNSIGNED-PAYLOAD, indicating that signature authentication is not performed on the request body. This parameter is mandatory when the body is input as a file.
   body	N/A	No	The JSON format is supported, for example, "{\"xxx\":\"xxx\"}".

   1. If the request body is in JSON format:

      r = signer.HttpRequest("POST",
                             "https://1684994b180244de9d141c00d3e52c73.apig.exampleRegion.huaweicloudapis.com/v1/infers/exampleServiceId",
                             {"x-stage": "RELEASE","Content-Type":"application/json"},"{\"xxx\":\"xxx\"}")

   2. If the request body is input as a file, construct the request body in multipart/form-data format.

      Request body format: files = {"Request parameter": ("Load path", File content, "File type", Request header)}

      Table 3 files parameters

      Parameter	Description
      Request parameter	Enter the parameter name of the real-time service.
      Load path	Path in which the file is stored.
      File content	Content of the file to be uploaded.
      File type	Type of the file to be uploaded, which can be one of the following options: txt: text/plain jpg/jpeg: image/jpeg png: image/png
      Request header	You are advised to set this parameter to {}. The request header is specified by header in HttpRequest.

      The following figure shows an example of accessing a real-time service with request parameter images.

      Figure 8 Accessing a real-time service
      

      1 2 3

      r = signer.HttpRequest("POST","https://63fb035aeef34368880448a94cb7f440.apig.cn-north-4.huaweicloudapis.com/v1/infers/76c41384-23ab-45f9-a66e-892e7bc2be53", {"x-stage": "RELEASE", "x-sdk-content-sha256": "UNSIGNED-PAYLOAD"}) files = {"images": ("flower.png", open("flower.png", "rb"), "image/png", {})}

4. Execute the following function to add the X-Sdk-Date header and Authorization header used for signature to the request:

   1	sig.Sign(r)

5. Call the API and check the result.

   resp = requests.request(method,url, headers, data, files)

   Table 4 Request parameters

   Parameter	Description
   method	Request method of the signed request object.
   url	Request URL of the signed request object.
   headers	Headers of the signed request object.
   data	Body of the request object, which can only be in JSON format.
   files	Request body in multipart/form-data format.

   1. If the request body is in JSON format:

      1 2 3

      resp = requests.request(r.method, r.scheme + "://" + r.host + r.uri, headers=r.headers, data=r.body) print(resp.status_code, resp.reason) print(resp.content)

   2. If the request body is input as an image:

      1 2 3

      resp = requests.request(r.method, r.scheme + "://" + r.host + r.uri, headers=r.headers, data={}, files=files) print(resp.status_code, resp.reason) print(resp.content)