Editing HTTP (section)

=== Request and response messages through connections ===
Data is exchanged through a sequence of [[Request-response|request–response messages]] which are exchanged by a [[session layer]] transport connection.<ref name="rfc9110-3.3" /> An HTTP client initially tries to connect to a server establishing a connection (real or virtual). An HTTP(S) server listening on that port accepts the connection and then waits for a client's request message. The client sends its HTTP request message. Upon receiving the request the server sends back an HTTP response message, which includes header(s) plus a body if it is required. The body of this response message is typically the requested resource, although an error message or other information may also be returned. At any time (for many reasons) client or server can close the connection. Closing a connection is usually advertised in advance by using one or more HTTP headers in the last request/response message sent to server or client.<ref name="rfc9112-9.1">{{cite IETF |rfc=9112 |sectionname=Connection Management: Establishment |section=9.1 |title=RFC 9112, HTTP/1.1}}</ref>