Caching

Well there is page caching and more granular caching including function caching (such as database queries).

Page Caching

Pages are cached server-side… eventually as content and also as a whole page (including “skin” and anything from the render engine).

Server-side page caching duration (cache lifetime) is defined by the $HS_config['cachingLifetime'] setting in config_site.php.

Defining non-cachable blocks

Idea 1 (orig.)

To define something as non-cacheable simply print (such as by closing any open <?php ?> tags) the following:

[?php[
//Your code goes here. For example:
print('Copyright '.date(Y).' Alan Hogan');
//Note that you do NOT need <?php ?> tags; they are inserted
//for you.  Think of [php[ /* ... */ ]php] as the same thing, but
//superdynamic and uncacheable.
]?]

Idea 2 (somewhat standard)

Maybe we will support

<nocache> /* code */ </nocache>

syntax like some other CMSes do.

Idea 3 (pretty friggin sweet)

Actually use PHP syntax, but surround non-cacheable bits with the /*nocache*/ ... /*endnocache*/ markers.

Code blocks that should be executed for both “compiling” (cacheable) and dynamic (non-cacheable) operations should be surrounded with /alwaysrun/ … /endalwaysrun/

The advantages of this:

Normal code editors & highlighters will work as expected
Don’t have to open and close <?php ?> tags all the time. NOTE: Code between the /*nocache*/and /*endnocache*/ markers should contain only complete PHP commands, that is:
```
print "Hello";
/*nocache*/ 
print "Current date and time is ".date("Y-m-d H:i:s')."";
/*endnocache*/
print "Good bye";
```
is good while
```
print "Hello"
/*nocache*/ 
."Current date and time is ".date("Y-m-d H:i:s').""
/*endnocache*/
."Good bye"; 
```
is bad, because in the latter case, after “compiling” the PHP interpreter will not have a whole statement to execute, and nothing will ever get printed.

As an aside, there is no reason not to embed HTML in nocache blocks, e.g. like:
```
/*nocache*/ 
?> 
if($foo) {
 Currently we are foo!
<?php 
}
/*endnocache*/
```
However one issue to keep in mind is that /*nocache*/ ... /*endnocache*/, if not surrounded by backticks (`) to let it know it’s code, will actually be considered italic by Markdown, and converted to /nocache/ … /endnocache/.

Module Caching

Names of things being cached should not have any underscores (_). Those are reserved to separate logical hierarchies; that is, within the “modules” group of caches, if a module is the “timebomb” module (I made that up), and it caches a “clock” then its name is “clock”, not “my_clock” or anything… so the effective name that cache_light sees is “timebomb_clock”. That should make sense because clock is owned by timebomb; it is beneath it in a hierarchy.