Five Ways to Consume a REST Service with PeopleSoft

PeopleSoft includes facilities for providing and consuming REST. A service provider is a listener. A provider waits for requests and responds accordingly. To provide web services, we must register metadata with Integration Broker. The process is pretty well fixed. Consumption, on the other hand, is much more flexible. Consuming a REST service means invoking (or calling) someone else's listener. The consumer initiates the conversation. In a consumption scenario, we might be sending data, receiving data, or both.

Here are five ways a PeopleSoft developer might invoke a REST service:

1. Metadata

This is the traditional PeopleSoft approach and follows the same pattern as providing services through Integration Broker. Here are a few of the metadata items a developer would create:

• Documents,
• Messages,
• Service, and
• Service Operation.

After creating and registering somewhat reusable metadata, the developer would then write PeopleCode to:

• Create Document structures,
• Invoke the service, and
• Parse the response.

Even though this approach requires the most effort and offers the least reuse, it takes full advantage of Integration Broker's capabilities, including logging, security, etc.

Metadata, in general, offers the following benefits:

• Reuse (ability to use the same definition multiple times),
• Documentation (describes an object),
• Reporting (query and analysis), and
• Transformation (ability to upgrade and transform based on architecture changes).

Pure code solutions are much harder to query and transform. Metadata is what allowed PeopleSoft to switch from a Windows-based Client/Server solution to its Pure Internet Architecture in (mostly) one release. Metadata is what allowed Integration Broker to transform from an XML-focused solution into an SOA solution in one release (the 8.48 transform). If these benefits sound appealing, then metadata may be the right choice for you.

2. Application Services Framework

Created initially as a REST provider to support digital assistants, the Application Services Framework can now consume REST services. The Application Services Framework is a developer-friendly configuration layer tightly integrated with Integration Broker metadata. Rather than directly working with SOA-oriented metadata, the Application Services Framework allows developers to create solutions using REST terminology and REST patterns.

To use the Application Services Framework for consumption, a developer would:

• Register the target service with the Application Services Framework, which includes describing the URL, parameters, headers, and payload (both request and response).
• Write PeopleCode to invoke the endpoint service.

This is one of the most important chapters in our updated Integration Tools curriculum. You may find basic information (including code samples) on consuming a REST service in PeopleBooks.

3. %IntBroker.ConnectorRequestURL

If your request is a simple URL with no special headers (request or response headers) and any parameters may be passed through the URL, then this is the most straightforward approach:

Local string &response = %IntBroker.ConnectorRequestURL("http://rest.example.com/endpoint");

Unfortunately, this solution offers no logging, header control, or any typical Integration Broker or integration features. It is strictly for the simplest GET requests. Nevertheless, by using URL definitions, this alternative may be one of the better alternatives for cross-environment migrations.

4. Code-only

The challenge with the first option, Metadata, is that it requires creating, migrating, and maintaining a significant number of definitions that provide little (if any) value for REST. For example, the URL of a PeopleSoft REST consumer service becomes part of the metadata. If you have different targets between DEV, TEST, and PROD, then you must modify the metadata after every migration. Implementing a true PeopleSoft Metadata-focused solution (such as option 1) may require you to violate development best practices by making changes after each migration.

Since all approaches require PeopleCode, why not skip the Integration Broker metadata in favor of your own reusable best practice-based metadata? You may find an example of this approach in our blog post Simple Code-only REST Request. With this approach, you are responsible for managing URLs, Credentials, etc., but you may store them in a manner that allows for reuse and better migration management. For example, you might create URL definitions that point to different endpoints in DEV, TEST, and PROD.

It is important to note that this approach DOES use metadata, but it reuses generic PeopleTools-delivered definitions, so we don't have to create new definitions.

As mentioned earlier, code doesn't report or transform well, so this alternative may miss out on future automated transforms, such as the 8.48 automated transform. Likewise, integrations launched in this manner won't log details in the Synchronous Service Operation Monitor. Nevertheless, this approach is becoming one of our favorite alternatives to overly complicated metadata.

5. Java

Using Java allows a PeopleSoft developer to bypass Integration Broker altogether. We put this option last because it should be the choice of last resort. However, it is probably the most flexible option available, allowing for everything from simple low-level sockets to convenient libraries, such as Apache's HttpClient (now included with PeopleTools).

There are many reasons to choose this option, but here are the two most common:

• Processing binary data: Integration Broker is pretty much an XML workhorse. Everything passing through Integration Broker is wrapped in XML at some point. Unfortunately, that might not work well with binary data. Therefore, skipping Integration Broker may be appropriate.
• Processing large amounts of data: Integration Broker works with DOM. It requires all data to be loaded in memory at one time. This makes it a poor choice for handling large datasets. An alternative is to use stream processing with an event-based parser, such as a SAX parser. With Java, you can read bytes, process them through an event-based processor, and then discard the processed bytes.

The challenge with using Java directly from PeopleCode is that many Java methods and constructors use overloading. As a workaround, we devised a strategy for invoking Java through JavaScript from PeopleCode. With a small PeopleCode fragment, we can invoke a JavaScript, and JavaScript handles Java really well. Details about this strategy are available in our Blog Post JavaScript on the App Server: Scripting PeopleCode.

The following is a sample JavaScript we used at Reconnect 2024 to stream-processed a large amount of JSON data from a REST service.

At JSMpros, we teach all five options in our Integration Tools and Integration Tools Update courses. Check out our website for on-demand and live course offerings. Alternatively, subscribe to gain access to all of our on-demand courses.