Using an API Tool to Call an API Which Uses App Authentication

APIs using app authentication can be bound to different apps, which provides the highest security level. To use an API tool to call an API which uses app authentication, you need to manually generate authentication information using demo.html in the JavaScript SDK package.

This section uses Postman as an example to describe how to use an API tool to call an API which uses app authentication. The procedure is as follows:

Obtaining App and API Information: Prepare key information of the app and API.
Obtaining the JavaScript SDK Package: Download the JavaScript package and verify its integrity.
Generating Authentication Information: Generate authentication information manually using demo.html in the JavaScript SDK package.
Calling an API: Use Postman to call the API.

Prerequisites

An API or API workflow using app authentication has been published. The published API is available in DataArts Catalog.
An App has been created and the API has been authorized to the app. That is, the API developer has completed the operations in Authorizing an API Which Uses App Authentication to Apps, or the API caller has completed the operations in Applying for API Authorization.
The static parameter defined in input parameters of the API has been configured during API authorization.
Postman has been installed. If it has not been installed, download it from the Postman official website and install it.

Notes and Constraints

Before calling an API which uses app authentication, you must perform the operations in Authorizing an API Which Uses App Authentication to Apps or Applying for API Authorization.
If a static parameter is defined in input parameters of the API, the static parameter value must be set during API authorization. Otherwise, an error indicating that the static parameter value is missing will be reported when the API is called using a tool.
To call an API in DataArts DataService locally, you need to bind an EIP to the DataArts DataService Exclusive cluster when creating the cluster.
The validity period of the authentication information generated using demo.html is 15 minutes. When the validity period expires, the authentication information becomes invalid.

Obtaining App and API Information

Log in to the DataArts Studio console by following the instructions in Accessing the DataArts Studio Instance Console.
On the DataArts Studio console, locate a workspace and click DataArts DataService.
In the left navigation pane, choose an edition, for example, Exclusive Edition. The Overview page is displayed.
Obtain the AppKey and AppSecret of the app authorized by the API. (If multiple apps have been authorized, you only need to obtain information about one of them.)

In the navigation pane on the left, choose Apps. Locate the app to which the API has been authorized, click the app name to access its details page, and record the AppKey and AppSecret.

Figure 1 Recording the AppKey and AppSecret
Obtain the URL, request method, and input parameters of the API to be called.

In the navigation pane on the left, choose APIs. Locate the API to be called, click the API name to access its details page, and record the URL, request method, and input parameters of the API.
- URL for calling the API: The exclusive edition supports both private and public IP addresses. To use the public IP address, you need to bind an EIP to the cluster during cluster creation. If you want to call an API in DataArts DataService Exclusive locally, you need to use a public IP address to ensure network connectivity.
- Input parameters: In this example, an API with various input parameter locations is created to describe how to enter various input parameters during an API call. Static is a static parameter that does not change with the value transferred by the API caller. Therefore, you do not need to set Static when calling an API.
  Figure 2 Recording the URL, request method, and input parameters

Obtaining the JavaScript SDK Package

On the DataArts DataService console, choose SDKs in the navigation pane. On the displayed page, download the JavaScript SDK.

Figure 3 Downloading the JavaScript SDK
Verify integrity of the SDK package. In Windows, open the CLI and run the following command to generate the SHA-256 value of the downloaded SDK package. In the command, D:\javascript-sdk.zip is an example local path and name of the SDK package. Replace it with the actual value.
```
certutil -hashfile D:\javascript-sdk.zip SHA256
```
The following is an example command output:
```
SHA-256 hash value of D:\javascript-sdk.zip
43da0b54d6b04d1f5ed7f278c2918c2a63a1ddb8048e2d1c5db60baafb17663c
CertUtil: -hashfile command executed.
```
Compare the SHA-256 value of the downloaded SDK with that in the command example. If they are the same, no tampering or packet loss occurred during the package download.

Generating Authentication Information

Decompress the SDK package, double-click the demo.html file, set the following parameters, and click Send request to view the returned value:
- Key and Secret: AppKey and AppSecret of the app authorized by the API, which can be obtained by referring to Obtaining App and API Information.
- Method and Url: API request method and calling URL, which can be obtained by referring to Obtaining App and API Information.
  If input parameters include Path and Query parameters, you need to change the {path} variable in the API calling URL to the value of the Path parameter, and add the value of the Query parameter to the end of the API calling URL in the following format: ?Query parameter name=Query parameter value, for example, ?query=1 in this example.
- Headers: Leave it empty even if it has been defined.
- Body: Use braces ({}) to enclose a string in "Body parameter name":Body parameter value format, for example, {"body":4} in this example.
Figure 4 Generating authentication information

Record the content of X-Sdk-Date, Authorization, and X-Authorization in the return. In this example, you need to copy the following content:

...
X-Sdk-Date: 202********55Z
...
Authorization: SDK-HMAC-SHA256 Access=4e7********d6c, SignedHeaders=host;x-sdk-date, Signature=4bf2********4e2
X-Authorization: SDK-HMAC-SHA256 Access=4e72********d6c, SignedHeaders=host;x-sdk-date, Signature=4bf2********4e2
...

Calling an API

Start Postman and add an API request.
Configure the API request as follows:
- Request method and calling URL: Obtain them by referring to Obtaining App and API Information. The values must be the same as those in Generating Authentication Information.
  Figure 5 Request method and calling URL
- Params: If the Query parameter has been added to the end of the calling URL in the ?Query parameter name=Query parameter value format, the value of Query Params is automatically generated. Otherwise, you need to enter a value.
  Figure 6 Params
  If you want to customize the calling result, set the following Query parameters:
  - (Optional) Pagination configuration: By default, the system assigns pagination data to the APIs created using configuration or a script/MyBatis. If you want to obtain specified pagination data, modify the following parameters. pageSize indicates the page size, and pageNum indicates the page number.
    Figure 7 Pagination parameters
    
    For APIs created using a script/MyBatis with custom pagination configuration, the pagination logic is written to the data acquisition SQL statement during API creation. Therefore, the pagination settings cannot be modified during an API call.
  - (Optional) Sorting configuration: By default, the system provides the default sorting based on the ranking parameters. By default, the custom ranking mode is ascending. To change the sorting, modify the pre_order_by parameter. The value of pre_order_by is in either of the following formats: Ranking parameter name:ASC (ascending order) or Ranking parameter name:DESC (descending order). Separate multiple ranking parameter descriptions by semicolons (;).
    Figure 8 Ranking parameters
    You can change the value of pre_order_by as follows:
    
    Delete an optional ranking parameter. The parameter is no longer used for ranking.
    
    Change the ranking mode of a ranking parameter whose ranking mode is custom to ascending or descending. The ranking parameter is sorted based on the new ranking mode.
    The value of pre_order_by cannot be changed in any of the following ways. Otherwise, the change does not take effect or an error is reported during API calling.
    
    If a mandatory ranking parameter is deleted, the parameter is still used for ranking and the deletion does not take effect.
    
    Adjustment of the sequence of ranking parameters will not take effect. The sequence of ranking parameters configured during the creation of an API through configuration, a script, or MyBatis will still be used.
    
    If you change the ranking mode of a ranking parameter whose ranking mode is ascending or descending, the API cannot be called. Such a change is not allowed.
  - (Optional) Number of returned records: If Return Total Records is enabled during API creation, it takes a long time to obtain the total number of data records if the data table corresponding to the API contains a large amount of data. In this case, if you do not want the system to calculate and return the total number of data records during an API call, you can modify the use_total_num parameter. The use_total_num parameter specifies whether to calculate and return the total number of data records. If its value is 1, the total number of data records is returned. If its value is not 1, the total number of data records is not returned.
    Figure 9 Number of returned records
- Headers: Enter X-Sdk-Date, Authorization, X-Authorization, and their values recorded in 2 in sequence, and enter header and its value.
  Figure 10 Headers
- Body: Select the raw format and use braces ({}) to enclose a string in "Body parameter name":Body parameter value format, for example, {"body":4} in this example.
  Figure 11 Body
After configuring the API request, click Send to send a request to the server and check the returned result. If "errCode":"DLM.0" is returned, the API is successfully called. If the API call fails, rectify the fault based on the error message.

If the API call fails and message "Could not get any response" is displayed, disable SSL certificate verification or proxy as prompted, and try again.

Figure 12 Calling an API