Chapter 5 Designing the integration Layer • Restful: These services work with resources instead of operations. Communication between client and server happens using a Unified Resource Identifier (URI) over HTTP protocol using HTTP methods such as GET whenever someone needs to get the representation of an existing resource. PUT is used to add a new resource into the system. POST is to modify the existing resource, and DELETE is to remove the resource from the system. • While calling SOAP services from the client, the dispatcher in the web services would first deserialize the SOAP message, and then identify the operation from the message to be performed. Actions are mapped with the service methods, but while calling Restful services you have to identify the resources like a transaction, then the HTTP method (GET, PUT, POST, and DELETE) will identify the method to be called. Each method in web services is mapped with the HTTP method. • Integrating methods: Integration methods are decided on the basis of available interface and requirements of the integration patterns. We further explore integration methods in detail in this chapter. • Security: API layer security would raise the accessibility of the service calls. You need to ensure that only authenticated users of the application can access the API. It will differ on the basic of architectural pattern. • Monolithic architecture: In this architecture, the entire application is a process; the security module is implemented to provide authentication and authorization to the user. When a user logs in to the application, the security module of the application authenticates the user. After verifying the user details, a session is created for the user and a unique session ID is provided with the session. The session stores login user information such as name, permissions, and roles. The server is responsible for managing the session, and sends the session ID to the client and back to the server in subsequent requests. This session ID would be used to verify the user details. 152