Some Important Terms:
- Hypertext Transfer Protocol (HTTP) – A standard for making requests and responses between clients and servers.
- HTTP Servers – Computers running software like Apache or NGIX that understand HTTP requests and responses.
- HTTP Requests – Made from a client to a server. Several Request Methods like GET, POST, PUT, DELETE are available. More than just requesting information, can also do things like post new posts or pages in the case of WordPress or edit existing content.
- HTTP Responses – Made from a server to a client in response to a request.
- HTTP Messages – The bundle of data passed in requests and respones are referred to as messages. Includes  Request or Status Line,  Headers,  Message Body (optional)
- HTTP Status Line (w Responses) – Includes: HTTP Version, Status Code (1XX informational, 2XXX success, 3XX redirect, 4XX client error, 5XX server error)Examples:
HTTP/1.1 200 OK
HTTP/1.1 404 Not Found
- HTTP Headers – Includes metadata for each request and response sent. Standard header fields (or metadata options) exist and custom header fields can be created as well.
- HTTP Message Body – Optional data passed along with a request or response. For a POST request it could be the new post information like title and content. For a response we might get an HTML webpage or media asset or JSON in the case of the WP API.
A Brief History of HTTP
- 1989 – Tim Berners-Lee and his team at CERN
– Started with ability for a client to send a GET request to a server
- 1991 – V 0.9
- 1996 – V 1.0 – Opened a new connection for each request
- 1997 – V 1.1 – Allowed for single connection to be used for multiple requests
- 2015 – V 2.0 – Streams and Multiplexing
To Learn How to Make HTTP Requests