2PAF - is push technology possible?

Temp 07.02.2003 12:49

Explanation of terms: Server push and Client pull

Most chats use client pull to update the text. The browser (client) reloads the text frame every some seconds, mostly using the meta refresh tag. The disadvantages: you can see the new texts only after the next refresh, unnecessary usage of server resources due to often connection establishment and unnecessary traffic (old messages must be also transfered). Besides, a regular refresh of a frame is just disturbing.

It seems that there are two things called server push according to HTML chats. One of them is a technology only supported by Netscape browsers up to now. It is not the technology GTChat uses. Instead GTChat uses the feature of all popuplar browsers, that webpages are displayed even before they are completely transfered. The chat does not close the connection but send the text line after line as soon the users write it. Therefore the time delay and traffic are minimal.

There are some disadvantages as well. For an HTTP connection you need a perl process on the server. If the server has a limit for script execution time this process is killed and the user must log in again.

Another problem are proxy servers, that cannot work with permanent connections. In Germany those are mostly proxy servers of T-Online which fortunately are not mandatory for T-Online users. But for users who must use proxy servers of this kind GTChat provides a client pull mode (you have to select "safe mode" when you log in).

цитата с сайта:http://www.gtchat.de/main_en.html

Александр, возможно ли с помощью организовать эту самую пуш технологию?
Если да, то намекните как? Ну можно конечно и в подробностях расписать:)

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