Expose Integration Flow Endpoint as API and Test the Flow

Beginner

20 min.

SAP Integration Suite, Beginner, Tutorial, SAP Business Technology Platform, SAP BTP, Cloud Foundry runtime and environment

Define the endpoint of the integration flow developed in the last tutorial as an application programming interface (API).

You will learn

How to define and expose an integration flow endpoint as an API
How to assign a policy to your API

Karunaharan VMay 15, 2024

Created by

December 3, 2020

Contributors

Prerequisites

You have created and deployed an integration flow that reads product details using an OData connection. For more information, see Design and Deploy Your First Integration Flow.

Context

In this tutorial, you will define the endpoint of the integration flow developed in the last tutorial as an application programming interface (API).

In addition, you will assign a policy template to the API to define how the API is called. A policy defines, for example, how an API can be called. In this tutorial, you assign a policy that defines an authentication of the API according to OAuth 2.0 client credentials grant. It is a secure way to control access to an API.

After you have performed these steps, finally, you will call the API to fetch the product details.

Step 1
In this step, you copy the endpoint address of the integration flow.

Open your integration flow.

In the Deployment Status tab of the property sheet, choose the URL.

In the Endpoints tab, choose Copy icon.

Step 2

In this step, you define and expose an integration flow endpoint as an application programming interface

Choose Settings > APIs to provision the API Management capability. This provisioning might take a few seconds to complete. After the provisioning is complete, refresh your webpage.

The page is available only if you’re provisioning the capability as a first-time user.
Choose Configure > APIs > Create to create an API.

On the Create API dialog, next to Select: choose URL and specify the following parameters:

IMPORTANT : Paste only the endpoint URL till /http/products Otherwise, the scenario will not run appropriately.

Parameter	Settings
URL	Paste the integration flow endpoint address you have copied in step 1. It ends with `/http/products/details`. Note: paste only the endpoint URL till `/http/products` instead of `/http/products/details`.
Name	`RequestProductDetails`
Title	`Product Details API`
API Base Path	`/products`

Select Create.

On the landing page, choose Resources tab and then Add.
In field Tag enter Product Details, and in the field Path Prefix enter /details.
Under Operations, delete all tabs except the POST tab and choose OK.

The API Resource is displayed.
Choose Deploy to create and activate the API Proxy for your integration flow.
Choose the POST operation to display more details on the API. A default API definition in Open API specification format is also generated.
To update the generated API definition in Open API format, choose Edit > Edit in API Designer.

The API designer is opened.
In the editable section on the right part of the screen, make the following changes.

Change Payload to productIdentifier and add a row as shown in the following screenshot.

TIP: Instead of copying the example, type it manually.

Choose Save.
Choose RequestProductDetails and then the Resources tab. Then, choose Edit > Edit in API Designer.

Now choose the POST request. You notice the API changes, in particular, the request body contains now one element with a product identifier.
When you choose Try Out and then Execute, since no authentication details have been configured, you get an error message with error code 401 (not authorized).

With this step, you have successfully created an API Proxy for your integration flow and generated an API documentation for your REST API in OpenAPI format.

Step 3
In this step, you’ll copy the client ID, client secret, and token URL from the service key that you automatically generated in your SAP BTP account. See: Set Up Integration Suite Trial.

In your SAP BTP subaccount, navigate to your service instance page. Choose Services > Instances and Subscriptions.

Under the Instances section, look out for the service instance that was created. Choose the key under the Credentials column to open the service key.

TIP: In trial accounts, the default name that the booster provides for the service instance is default-it-rt-integration-flow. In free tier accounts, the instance name is user-defined.

Copy the values of clientid, clientsecret and tokenurl parameters. These are the credentials that you use to make a request to your integration flow.
Step 4
In this step, you assign a policy template to your API to specify authentication details for the API call. In particular, you use a policy template that defines that the caller of the API authenticates itself using OAuth 2.0 client credentials grant.

This grant type works in the following way: In a first call, the API client provides the values of clientid and clientsecret (from the service key generated in Step 1) to a token service (the URL of the token service is also contained in the service key definition). The token service provides an access token to the API client. In a subsequent call, the API client calls the integration flow endpoint providing the access token. If the access token is valid, the API client is authorized to call the integration flow.

Choose Discover > APIs.

Search for the package Connect to SAP Business Technology Platform Services and select it.

Navigate to Artifacts tab.

Under Actions, choose Copy.

After the success message is displayed, navigate to the Configure > APIs.

Choose the API that you created in the previous step.

Choose Edit.

Select Policies.

The Policy Editor opens.

Choose Policy Template –> Apply.

Select the template Cloud_Platform_Connectivity and choose Apply.

Open the node Target Endpoint.

Choose PreFlow.

In the editor, the OAuth workflow defined by the policy is visualized as a graphical model.

Now, you need the values copied from the service key: clientid, clientsecret and tokenurl.

In the graphical model of the Policy Editor, choose the getcredential shape.

Paste the value of clientid and clientsecret as shown in the following image.

In the Policy Editor, choose the getoauthtoken shape.

Paste the value of tokenurl as shown in the following screenshot.

Note: Make sure that you append ?grant_type=client_credentials to the token URL that you pasted.

Select Update.

Select Save.

Select Click to Deploy.

Confirm the deployment.

You have assigned a policy template now.

Which of the following values are mandatory to authorize the API client and to call an integration flow as an HTTP endpoint?
clientid
roles
clientsecret
url
tokenurl
Step 5
In this step you try out the API to get product details as a response from the remote component.

Go to the Resources tab.

Choose Try Out.

Choose Execute.

As result, you see the response from the WebShop with the product details for the given product identifier.
Step 6
You have successfully set up your Integration Suite tenant, designed a simple integration flow that reads data from a remote component, and defined the integration flow endpoint as an API. Finally, you have successfully called the API to get product details as a response from the remote component.

This scenario showed you how to use Integration Suite, and in particular, its Cloud Integration and API Management capabilities seamlessly integrated, end-to-end.