HTTP is the foundation of data communication on the World Wide Web (WWW). Its primary purpose is to enable the transfer of web resources such as HTML documents, images, and other multimedia files between a client, typically a web browser and a server.
Because HTTP enables communication between user applications and the network, it is considered an application layer protocol, and as a connectionless protocol, it independently treats each request-response operation. In addition, HTTP uses a client-server model, is text-based, and typically operates over TCP/IP, making it suitable for web browsing and resource retrieval.
As you can see in the image above, the request-response cycle of the HTTP client-server involves several steps:
- Client Sends a Request: The client initiates communication by sending an HTTP request to a specific web server, specifying the desired resource, such as a web page or an image, and the HTTP method, such as GET, for retrieval.
- Server Processes the Request: The web server receives, processes, and retrieves the requested resource.
- Server Sends a Response: The server sends an HTTP response to the client containing the requested resource and metadata, such as status codes and headers.
- Client Receives the Response: The client's web browser renders the received content, displaying the web page or multimedia element to the user.