Learn about the Hypertext Transfer Protocol (HTTP), including the request-response cycle, methods, and status codes.
Hypertext Transfer Protocol (HTTP) is the foundation of data communication for the World Wide Web. It's a client-server protocol, meaning requests are initiated by the recipient, usually a web browser (the client). A complete document is reconstructed from the different sub-documents fetched, such as text, layout description, images, videos, scripts, and more. The core of HTTP is the request-response cycle. When you type a URL into your browser, it sends an HTTP request to a server. This request includes a method (like GET to retrieve data or POST to submit data), the path to the requested resource, and headers containing additional information. The server receives this request, processes it, and sends back an HTTP response. The response contains a status code, headers, and often a body with the requested resource (like an HTML file or JSON data). Common HTTP methods (or verbs) include GET (requests a representation of the specified resource), POST (submits an entity to the specified resource, often causing a change in state or side effects on the server), PUT (replaces all current representations of the target resource with the request payload), and DELETE (deletes the specified resource). HTTP status codes are crucial for understanding the result of a request. They are grouped into categories: 1xx (Informational), 2xx (Success, e.g., 200 OK), 3xx (Redirection), 4xx (Client Error, e.g., 404 Not Found), and 5xx (Server Error, e.g., 500 Internal Server Error).