UNIT 9

Development of Interface-based Programming

9.1 Development of Interface-based Programming :

WSDL Bindings:

WSDL binding describes how the service is bound to a messaging protocol especially SOAP messaging protocol.

The binding element has two attributes:

     Name attribute – defines the name of the binding.

     Type attribute – points to the port for binding.

Binding to SOAP

Example :A request-response operation

9.2 Reusable Web Services Infrastructure.

• Reusable interfaces by design need to be flexible.

For example, filter string parameters should enable a developer to dynamically query any SQL database or NoSQL document store. In the same transaction the service should support arrays of objects and related objects in return. This supports a huge number of access patterns “out of the box” without the need for further customization.

• A server-side scripting and customization engine should modify requests and responses to handle formula fields, workflow triggers, special access controls, field validation, and custom usage limitations.
• The scripting engine can be used to implement custom services when necessary. Access to external web services is another way to extend the functionality of a reusable REST API services platform.

Making Comprehensive and Reusable APIs Work for You

• When a company adopts a strategy based on comprehensive and reusable interfaces.
• System administrators set up the back-end infrastructure and specify user access rights, and then application designers can safely build anything they want on top of that platform.
• This “decouples” client-side application development from server-side security, user management, and administration.
• Client-side developers can use the same REST API for each new project.
• They can now tap into a universal data access layer to power their applications — the back-end work is already taken care of for them.
• They might use different parameters or data objects, but the programming style is the same.
• A well-designed API can also minimize the differences between SQL, NoSQL, and file storage. Add filter string to file storage and you get NoSQL.
• Add object enforcement and metadata to NoSQL and you get SQL. Consistent and well-designed services provide a much easier way to learn the API and write applications. 
• The applications written on a service platform also benefit from the virtualization provided by the service layer.