Caching a custom snippet - Best practice

33 Posts

hvoort Reply #1, 10 years, 7 months ago

Hi all,

What are the best practices for caching a snippet with some custom data calls?

I'm interested in the caching the output of a custom snippet after some db-calls and data processing stuff. First I've a question about caching details by not using the not-cache flag [[!any]], second I'm interested in the comparison of the cache flag and the use of cacheManager in a snippet.

1.
Does caching using the cache flag at a snippet takes into account arguments? e.g. [[snippet? &arg=`1`]] and [[snippet? &arg=`2`]]. Are these snippet calls cached separately?

2.
Assuming the cache flag takes into account the arguments (as asked in 1.);

Which caching method is better?

Without the cache flag at the snippet call; [[snippet? &arg=`1`]]. If so, how can I clear this snippet cache when custom objects change?
With the cache flag, using the cacheManager; [[!snippet? &arg=`1`]] using $modx->cacheManager within the snippet.

I appose option 1 is quicker, because it saves a snippet call including some cache calls, and the cache is saved together with the resource (??).

Thanks in advance!

Huub

I love flexibility

14 Posts

yuka123 Reply #2, 10 years, 7 months ago

http://rtfm.modx.com/revolution/2.x/developing-in-modx/advanced-development/caching

This is a good read on Caching I think.

Usually I just use getCache snippet (available on addons), and wrap a custom snippet, cache it to custom partition. Then you can create an action menu to just clear that partition, or do that elsewhere..

http://modx.com/blog/2012/10/29/optimization-with-getcache-and-custom-cache-partitions/

This is also a good read.

Alex

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2,475 Posts

Everett Reply #3, 10 years, 7 months ago

See http://rtfm.modx.com/xpdo/2.x/advanced-features/caching/caching-tutorial-lifetimes

If you don't use a custom partition, the cached stuff will get cleared when the site's cache is cleared. Otherwise, you should write a CMP to clear your custom partition or create a plugin to clear the custom partition (e.g. tie it to the regular cache-clearing event), e.g. something simple like

$cache_dir = 'your_custom_partition';
if ($modx->event->name == 'OnBeforeCacheUpdate') {
    $dir = MODX_CORE_PATH .'cache/'.$cache_dir;
    $objects = scandir($dir);
    foreach ($objects as $object) {
        if ($object != '.' && $object != '..') {
            if (filetype($dir.'/'.$object) != 'dir') {
                @unlink($dir.'/'.$object);
            } 
        }
    }
    reset($objects);
}

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33 Posts

hvoort Reply #4, 10 years, 6 months ago

Thanks both for the replies!

I am familiar with the custom caching partitions, the reason I raised this question is because I'm interested in the normal behavior of the snippet caching by MODx. When using a snippet call with dynamic parameters it looks like only the result of the first request to the snippet is cached, and the snippet code itself.

An Example:

A document content contains: [[foo? &arg=`[[!getUrlParam? &name=`bar`]]`]]
Then this page is requested with parameter bar filled (index.php?id=42&bar=1)
Now this page is requested with another value in that parameter (index.php?id=42&bar=2)
Then looking into the resource cache (/core/cache/resource/web/resources/42/*.cache.php)
! - I found the snippet code itself (of foo), the snippet call with the first parameter value [[foo? &arg=`1`]], and the snippet call with the getUrlParam call in it [[foo? &arg=`[[!getUrlParam? &name=`bar`]]`]].

What I'm missing is the caching of all the other snippet outputs, dependent on their input values. Is this default behavior, and why does the system not uses a cache for snippet outputs?

===================
Btw: I'm now using a custom cache partition for the snippet result, but was (and still am) wondering if a normal snippet cache (described above the horizontal line) has a better performance.

I love flexibility