What is the HTTP protocol?

Hypertext Transfer Protocol (or HTTP) is the basis of data transfer for the World Wide Web. Such protocols are structured text that uses logical links (hyperlinks) between nodes that contain certain data. Thus, it is a way of exchanging or transmitting hypertext.

The HTTP protocol acts as a request-response function in the client-server model of calculations. So, the web browser acts as a client, and the hosting site is a server. The client sends an HTTP request message to the server that provides specific resources (for example, HTML files and other materials), and then returns a response message. The response contains information about the request, and can also contain the requested content in the body of the message.

The browser is the main example of a user agent (client). Other types of custom agents include software used for indexing by search providers, mobile applications and other resources that use or display web content.

The HTTP protocol is designed to provide intermediate elements of the network to enhance or provide communication between clients and servers. Sites with large traffic often benefit from the cache of web servers that display content on behalf of upstream resources, reducing download times. The cache of web browsers allows the user to reduce network traffic. A proxy server that uses the HTTP protocol on the local network can provide communication for clients that do not allow global address routing by relaying messages from external servers.

An HTTP session is a sequential process from queries and responses. The client initiates the request by creating a TCP connection to a specific port on the server, and the latter listens to this port and waits for the request message. When it is received, the server sends a response message in the status bar . The body of this message is usually a requested resource, although an error message or other information may be displayed.

If you consider the purpose of the HTTP protocol, it should be noted that it defines methods to indicate the desired action performed on the identified resources. In this case, the type of information displayed (previously existing data or generated dynamically) depends on the implementation of the server. Often, such a resource corresponds to a file or script located on the hosting.

Some methods that use the HTTP Hypertext Transfer Protocol are intended only for searching information and should not change the state of the server. In other words, they do not have a serious impact, with the exception of relatively harmless effects - caching or increasing visitor statistics.

On the other hand, the HTTP protocol can also use methods that are designed for actions that can affect either the server or other external resources - activate financial transactions or perform e-mail transmission. Occasionally, such methods are used by web robots or some sites and can make requests regardless of the main task.