The Miracle of HTTP

The web is now all pervasive in the majority of peoples lives, sometimes its explicit when we are surfing the web and sometimes is implicit for example in relation to the rise of the Internet of Things.

The complexity of the implementation of the web is on a scale that can cause you to wonder how this thing always keeps working. The perceived speed of advances in the capability of the web can lead you to think that the technology is constantly evolving and refining.

Whilst this may be true for the technologies that enable us to implement things on the web, many of the underlying technologies that underpin the web and keep it working have remained surprisingly static since its inception.

Once of these technologies is the Hypertext Transfer Protocol (HTTP).

What Did HTTP Ever Do For Me?

HTTP is a request\response protocol that allows clients, for example your desktop browser, to request data from a server, for example the server allowing you to read this blog.

It acts within the application layer of the Internet Protocol suite and handles the transfer of resources, or hypermedia, on top of a transport layer connection provided by protocols such as the Transmission Control Protocol (TCP).

It is a descriptive protocol that allows requests to describe what the user wants to do with the indicated resource, to this end each request uses an HTTP verb such as GET, POST, PUT and DELETE and each response uses status codes such as OK, NOT FOUND, FORBIDDEN to form an exchange that describes the interactions during a session.

Each request and response also contains certain Header Fields that can be used to further describe both the contents of the request\response and the parties sending them.

If you were to see an exchange of HTTP requests between your browser and a web site you would be surprised at how much it is human readable, understandable and intuitive. This speaks volumes for the initial design of the protocol and it's elegant simplicity.

Without HTTP we wouldn't have a way to allow the enormous amount of data on the internet to be queried for, retrieved, uploaded or managed.

The Brief History of HTTP

Given the importance of HTTP you may think that it has been under constant revision and refinement as the use and the size of the web grows.

Actually this is not the case, the first published version of the HTTP protocol (v0.9) was published in 1991. This was followed by v1.0 in 1996 and v1.1 in 1997, with v1.1 of the protocol still being the prevalent driving force behind the majority of web usage.

Over the intervening years there have been clarifications and refinements to v1.1 and the built in extensibility designed into the protocol has allowed improvements to be made, but still the protocol delivering the majority of the benefits we derive from the web has remained largely unchanged since what most would consider the birth of the public use of the internet.

This really does go to show the benefit of designing for simplicity, if you develop robust and descriptive technology this can be the mother of invention when creative people pick up the tool you've provided them and combine it with their imagination.

What The Future Holds

So does all this mean that HTTP is done and dusted with all problems solved? Well no, our use of the web and the nature of the data we channel through it have changed since the 90's and while HTTP is able to service our demands there is scope for improvement.

HTTP/2, derived from Google's experiments with the SPDY protocol, is a major release and update to the HTTP protocol. It focuses on performance and efficiency improvements to adapt HTTP to the ways in which we now use the web.

Officially standardised in 2015 the backwards compatibility of HTTP/2 with HTTP v1.1 allows the adoption of the new protocol to spread without fundamentally breaking the web.

As of 2018 around 30% of the top 10 million web sites support HTTP/2 with most major browsers also providing support for the new version of the protocol.

The substantial effort involved in being able to successfully advance a fundamental protocol such as HTTP whilst not breaking the web speaks to the relative slow progression of new versions of the protocol.

Its easy to take the web for granted without admiring the engineering that originally built the basis for all the future innovation that has subsequently changed all our lives. Anyone that has worked in an technological industry will to speak to the difficulty in getting things right and the normality of deciding this isn't going to work and being forced to start-over.

Whilst it would be misleading to assume this never happened during the development of HTTP, the small number of published versions of the protocol combined with the explosive and transformative impact of the web truly is something to behold and admire.

Next time your using the web, or an app, or talking to your smart speaker tip your hat to the engineering that not only made it all possible but that also provided the stability for the evolution that got us to this point.