One of the least known concepts in dynamic web development is known as the Edge Side Include or ESI for short. Similar to that of the Server Side Include while at the same time also similar to that of the Client Side Include, the ESI is solely used for the purpose of the scaling of the web infrastructure. In today’s day and age, virtually every single website out there is now running on some form of generated content. This dynamic content whether it is structural or navigational is an important part of the web development process and insures that the expansion of a website is a simpler task.
As more dynamically generated content is added to a website, the ability of the website’s caching system to keep up becomes increasingly difficult. As a result of this caching issue, Akami along with several other major development corporations, developed the concept of the edge side include and within no time, they submitted it to the World Wide Web Consortium for its approval.
This submission first occurred with the submission of the ESI Language Specification 1.0 back in 2001. Although the World Wide Web Consortium has since acknowledged the receipt of the draft proposal, they have yet to adopt it into the standards of web development.
Basically, these edge side include elements are inserted into the actual HTML code during the creation of the dynamic content by the web page script itself. These tags are XML based and instructs the server’s processor to take a particular action with regards to the content. It is used for the overall assembly of the web page in question and is used for the inclusion of data or content. In all simplicity, the closest correlation is to that of a mixture between the PHP include command and the Microsoft iFrame tag in which the XML can require the inclusion of a particular file or force a continuance of the remainder of the page assembly following an error.
While there is still yet to be an approval for the implementation of the Edge Side Include, development of the concept continues. For those who have any experience in the development of the web has heard of the name Akami in the past as they are known for their load bearing systems which are currently being used by Yahoo! as well as several other major websites all over the world. Original Authors: Nick
Edit Update Authors: M.A.Harris
Updated On: 30/01/2009