Preparing a WebHook in Fn

The Fn Project works best with functions written in Java. When calling a function, the framework would be able to automatically transform the body of the request as a parameter of the entrypoint method. In the following example, the JSON from the request will be converted into a string for the handleRequest method, the entrypoint method of this Fn function:

public Object handleRequest(String body) {
    if (body == null || body.isEmpty()) {
        body = "{}";
    }
     Input input;
    try {
        val mapper = new ObjectMapper();
        input = mapper.readValue(body, Input.class);
    } catch (IOException e) {
        return new Error(e.getMessage());
    }
     if (input == null) {
        return new Error(body);
     }
     /* process the rest of business logic */
}

Here's the list of data transfer object (DTO) classes to properly encode and decode Parse's WebHook messages inside an Fn function. With help from Project Lombok and Jackson, we can dramatically...