A web service client is a software component that interacts with a web service to access its resources and functionalities. According to our reference, a web service client accesses resources through a web service interface on behalf of a user via an application. Let's delve into this definition.
Understanding the Components
To fully understand what a web service client is, it helps to break down its components:
- Web Service: A standardized way of exposing application functionalities over a network, typically using protocols like HTTP, SOAP, REST, and standards like XML and JSON.
- Client: An application or component that requests services from the web service. This is the "user" in this context.
- Interface: The defined contract (usually in WSDL for SOAP or API documentation for REST) that specifies how the client should communicate with the web service.
- Resources: Data or functionalities that the web service exposes.
How a Web Service Client Works
The web service client acts as an intermediary between the user and the web service. Here's a simplified workflow:
- User Action: The user performs an action within the application, triggering the need for a web service interaction.
- Client Request: The web service client formulates a request, adhering to the web service's interface.
- Service Processing: The web service receives the request, processes it, and generates a response.
- Client Response Handling: The web service client receives the response, parses it, and presents the information to the user.
Examples
Let's consider a practical example based on the reference:
- Airline Reservation System: Imagine an airline reservation system. A web service client might be used to check a frequent flyer's accumulated points per hour of flight.
- The client sends a request to the "GetPoints" web service, including the user's frequent flyer number.
- The web service retrieves the point balance from its database.
- The web service sends the point balance back to the client.
- The client displays the point balance to the user.
Other examples include:
- Mobile App connecting to a Payment Gateway: A mobile app uses a web service client to send credit card information to a payment gateway for processing.
- E-commerce website integrating with a Shipping Provider: An e-commerce website uses a web service client to get real-time shipping rates from a provider like FedEx or UPS.
Key Characteristics of a Web Service Client
- Abstraction: It hides the complexity of the web service implementation from the user.
- Platform Independence: It can be written in various programming languages and run on different platforms, as long as it adheres to the web service interface.
- Loose Coupling: The client and web service are loosely coupled, meaning changes to one do not necessarily require changes to the other.
Benefits of Using Web Service Clients
- Reusability: Functionality exposed by the web service can be reused across multiple applications.
- Interoperability: Enables communication between applications written in different languages and running on different platforms.
- Scalability: Web services can be scaled independently of the client applications.
