$Web_Expire
Set expiration date/time of Web response
$Web_Expire sets the expiration date and time for the Web Server response entity being returned by the application. Using $Web_Expire, you can control how long a browser caches an entity returned by your application.
$Web_Expire requires one argument and returns a numeric status code. It is also callable.
Syntax
%rc = $Web_Expire( exp_time )
Syntax terms
| exp_time | A date/time expressed in seconds since 12 AM on January 1, 1900. You can use the $Web_Datens function to get the current date in this format, and manipulate it using standard User Language expressions. |
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Return codes
| Code | Meaning |
|---|---|
| 0 | Completed successfully |
| -1 | Not a web thread |
| -4 | Invalid datetime value |
Examples
Use $Web_Expire to control how long a browser caches an entity returned by your application.
* Get current date in binary %X = $WEB_DATENS * Add one week to the current date %X = %X + 7*24*60*60 * Ensure browser doesn't cache returned data * longer than one week %RC = $Web_Expire( %X ) * Changed my mind, only cache URL for 1 hour. * The previous $Web_Expire call is forgotten. %X = %X - (7*24-1)*60*60 %RC = $Web_Expire( %X )
In the above example, $Web_Expire is called to set the expiration date for the response entity. A second $Web_Expire demonstrates that you can override the $Web_Expire value any time you wish.