HTTP protocols

Brief History of HTTP

The Hypertext Transfer Protocol (HTTP) is one of the most ubiquitous and widely adopted application protocols on the Internet: it is the common language between clients and servers, enabling the modern web. From its simple beginnings as a single keyword and document path, it has become the protocol of choice not just for browsers, but for virtually every Internet-connected software and hardware application.

We will take a brief historical tour of the evolution of the HTTP protocol. A full discussion of the varying HTTP semantics is outside the scope of this lesson, but an understanding of the key design changes of HTTP, and the motivations behind each, will give us the necessary background for our discussions on HTTP performance, especially in the context of the many upcoming improvements in HTTP/2.

HTTP 0.9: The One-Line Protocol

The original HTTP proposal by Tim Berners-Lee was designed with simplicity in mind as to help with the adoption of his other nascent idea: the World Wide Web. The strategy appears to have worked: aspiring protocol designers, take note.

In 1991, Berners-Lee outlined the motivation for the new protocol and listed several high-level design goals: file transfer functionality, ability to request an index search of a hypertext archive, format negotiation, and an ability to refer the client to another server. To prove the theory in action, a simple prototype was built, which implemented a small subset of the proposed functionality: