Client–server model: Difference between revisions

Revision as of 01:01, 14 February 2025

Revision as of 00:09, 25 February 2025

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{{Short description|Distributed application structure in computing}}{{More citations needed|article (some sections)|date=March 2024}}[[File:Client-server-model.svg|thumb|250px|A computer network diagram of clients communicating with a server via the Internet]]

The '''client–server model''' is a [[distributed application]] structure that partitions tasks or workloads between the providers of a resource or service, called [[Server (computing)|servers]], and service requesters, called [[client (computing)|client]]s.<ref>{{cite web|url=http://java.sun.com/developer/Books/jdbc/ch07.pdf|publisher=Sun Microsystem|title=Distributed Application Architecture|archive-url=https://web.archive.org/web/20110406121920/http://java.sun.com/developer/Books/jdbc/ch07.pdf|access-date=2009-06-16|archive-date=6 April 2011}}</ref> Often clients and servers communicate over a [[Computer networking device|computer network]] on separate hardware, but both client and server may be on the same device. A server [[Host (network)|host]] runs one or more server programs, which share their resources with clients. A client usually does not share any of its computing resources, but it requests content or service from a server and may share its own content as part of the request. Clients, therefore, initiate communication sessions with servers, which await incoming requests.

Examples of computer applications that use the client–server model are [[email]], network printing, and the [[World Wide Web]].

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==Example==

When a [[bank]] customer accesses [[online banking]] services with a [[web browser]] (the client), the client initiates a request to the bank's web server. The customer's [[login]] [[credential]]s mayare becompared stored inagainst a [[database]], and the webserver accesses thethat [[database server]] as a client. An [[application server]] interprets the returned data by applying the bank's [[business logic]] and provides the [[Input/output|output]] to the webserver. Finally, the webserver returns the result to the client web browser for display.

In each step of this sequence of client–server message exchanges, a computer processes a request and returns data. This is the request-response messaging pattern. When all the requests are met, the sequence is complete and the web browser presents the data to the customer.

This example illustrates a [[design pattern]] applicable to the client–server model: [[separation of concerns]].