To design a complex Appian integration to call a RESTful API, you need to have some prerequisites, such as:
Define the HTTP method that the integration will use. The HTTP method is the action that the integration will perform on the API, such as GET, POST, PUT, PATCH, or DELETE. The HTTP method determines how the data will be sent and received by the API, and what kind of response will be expected.
Understand the content of the expected body, including each field type and their limits. The body is the data that the integration will send to the API, or receive from the API, depending on the HTTP method. The body can be in different formats, such as JSON, XML, or form data. You need to understand how to structure the body according to the API specification, and what kind of data types and values are allowed for each field.
Understand the different error codes managed by the API and the process of error handling in Appian. The error codes are the status codes that indicate whether the API request was successful or not, and what kind of problem occurred if not. The error codes can range from 200 (OK) to 500 (Internal Server Error), and each code has a different meaning and implication. You need to understand how to handle different error codes in Appian, and how to display meaningful messages to the user or log them for debugging purposes.
The other two options are not prerequisites for designing the integration, but rather considerations for implementing it.
Understand whether this integration will be used in an interface or in a process model. This is not a prerequisite, but rather a decision that you need to make based on your application requirements and design. You can use an integration either in an interface or in a process model, depending on where you need to call the API and how you want to handle the response. For example, if you need to update a case in real-time based on user input, you may want to use an integration in an interface. If you need to update a case periodically based on a schedule or an event, you may want to use an integration in a process model.
Understand the business rules to be applied to ensure the business logic of the data. This is not a prerequisite, but rather a part of your application logic that you need to implement after designing the integration. You need to apply business rules to validate, transform, or enrich the data that you send or receive from the API, according to your business requirements and logic. For example, you may need to check if the case status is valid before updating it in the legacy system, or you may need to add some additional information to the case data before displaying it in Appian.
