Comet Programming in Web Development

Comet programming is a web application model, which is used in web application development as an alternative to a page-by-page web model and allows web developers to sidestep the constraints of conventional polling techniques. Software development companies resort to Comet programming when being engaged in the development of event-driven web apps, since Comet programming techniques give an opportunity to update page components and enable real-time client-server interaction.

Comet programming: brief outline on its advent

Comet programming had been in use before the actual term for this set of web development techniques was coined. Previously, comet programming techniques were called Ajax Reverse, Two-way-web and HTTP streaming. The predecessor of the Comet web application model was a constraint to a quick page refresh as it was limited only to page-by-page updates whereas Comet programming techniques ensured the development of web applications with asynchronous refresh of separate page elements via a persistent HTTP connection, at the same time Comet client-server interaction enables handling other simultaneous calls in the meantime.

Comet programming techniques

Comet programming techniques fall into 2 broad categories:

• Streaming is a Comet programming technique implemented via Hidden iFrame (inline frame) or XHR server push approaches. These methods imply browser-side event processing and have two major hurdles for a wide utilization in web development: there is no efficient mechanism for fixing errors and no control over the status of the request calling process.
• Long Polling is a far easier and more productive Comet programming technique with several workarounds for streaming Comet problems and page-by-page model constraints. A call for updates is initiated on the client side and the connection remains open until the server has some data to push in response. After that, the client polls the server for further chunks of new data. Long Polling Comet technique allows circumventing the browser cashing of stale data as well as connection overloads.

Thus Comet Programming based on Long Polling is far more appealing and common method for dynamic web application development. In this case web professionals make use of native browser features such as JavaScript and premium web development technologies like Ajax to manage heavy inbound traffic and the demand for frequent data updates during the development of web applications.