[7180] in www-talk@info.cern.ch

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Re: Automatic Page Updates

daemon@ATHENA.MIT.EDU (Marc Salomon)
Tue Jan 10 17:10:06 1995

Date: Tue, 10 Jan 1995 23:09:03 +0100
Errors-To: listmaster@www0.cern.ch
Reply-To: marc@library.ucsf.edu
From: "Marc Salomon" <marc@library.ucsf.edu>
To: Multiple recipients of list <www-talk@www0.cern.ch>

<allocca@OpenMarket.com>
|>Is there any way in HTTP for a Server to automatically update a page
|>without requiring the user of the client to click on anything?

<mogens@CS.Stanford.EDU>
|Currently no.  HTTP is connectionless, and that makes it hard to
|do things after a transaction is completed.

Except perform another transaction :)

The problem is that the data change on the server side and there is no
way in the current HTTP model for the server to contact a client to
inform them of this.

A solution that would be within the http model would be for the server to
inform the client that the content of this document changes rapidly and a
interval for refreshed.  Something like:

C: GET /stock_quote.html HTTP/1.1
S: HTTP/1.1 200 OK
   Content-type: text/html
-->Refresh: <time_interval>
   Last-modified: Wednesday, 07-Dec-94 22:03:38 GMT
   Expires: Wednesday, 07-Dec-94 22:03:39 GMT
   Content-length: 1721

This would allow the client to set a timer and perform a GET on the URL
every time_interval so you would have the perception of a dynamically
updated document.  The updates would be dependent on the alarm clock, of
course, instead of any real change in the content of the document, but I
think its the closest you are going to get under the current scheme.

-marc

-- 

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