[wp-hackers] Transient key best practice

[Nikola Nikolov]

Otto - doesn't setting transient's expiry time automatically remove it from
the database once it's time's up? I haven't looked into core precisely how
this works, but it would make sense for expired transients to get
removed(during cron or whenever).


On Mon, Sep 9, 2013 at 11:25 PM, Otto <otto at ottodestruct.com> wrote:

> It is a very bad idea to use mutating keys for transients. You run the
> risk of storing transients in ways such that you never actually try to
> get them again, thus creating lots and lots of entries in the database
> for those transients, for no reason.
>
> The important part of a caching mechanism is that you read from the
> cache. If your key is constantly changing in a way that makes doing
> this read less likely, then your cache isn't very useful, is it?
>
> I would absolutely not include cache time or number of items in the
> key, because these can change and then you'll never look up that
> cached data again, leaving it orphaned.
>
> -Otto
>
>
> On Mon, Sep 9, 2013 at 2:38 PM, Micky Hulse <mickyhulse.lists at gmail.com>
> wrote:
> > Hello,
> >
> > I'm writing a class that gets a JSON response from YouTube's API and
> > caches the parsed data into a WP transient.
> >
> > I was tentatively planning on creating transient keys that look like:
> >
> > namespace_youtube:playlist_or_user|||cache_time|||number_of_items
> >
> > Where:
> >
> > 1. "namespace_youtube" = Make sure I don't stomp on other keys and
> > easier to find.
> >
> > 2. "playlist_or_user" = Will be either a playlist ID or a username.
> >
> > 3. "cache_time" = How long to cache this transient.
> >
> > 4. "number_of_items" = Number of videos that were cached in this
> transient.
> >
> > 5. "|||" = Just an easy delimiter for me to search on if I need to
> > get/parse transient keys.
> >
> > Goal:
> >
> > I want the ability to cache multiple different types of YouTube API
> > calls and have them be cached based on playlist ID or username, how
> > long it was it's supposed to be cached for and the number of items
> > cached. In other words, there might be times where I need to request
> > the same playlist but vary it's output by the cache time and number of
> > items requested from the API.
> >
> > Question(s):
> >
> > Based upon my goal, does the above transient key naming convention make
> sense?
> >
> > What's common transient caching naming practice for situations like I
> > describe above?
> >
> > For when it comes to transients, is there a way to have simpler
> > transient key (just simply "namespace_youtube", for example) naming
> > convention yet vary, and have the ability to access, the data stored
> > in that transient?
> >
> > Please let me know if I need to clarify my questions.
> >
> > Thanks!
> > M
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