[support] Issues with initializing Variables on startup..

Tue Jan 29 17:04:46 UTC 2008

Yes true, I was mistaken about the variables being instatitated. But
these values are initially loaded from the database by the variable_init
function, called in the drupal bootstrap process before settings.php is
loaded.  Yes you can override these in settings.php, in which case the
database value doesn't matter, but hey are still meant to be site
configuration values that do not change.  As the settings.php file
indicates you don't normally use this method, unless you're rally trying
to something vhost specific.  They are not intended to house global
variables that you intend to change during the page load.   Variable_set
is designed to change the database given values and is functioning as
designed.  It's used by the admin pages to alter the site specific
values.   

90% of all use cases are handled using variable_get() to get the site
specific configuration settings from the database and loaded in cache.
It's only in weird multi-site hosting cases that you would ever be
overriding the values retrieved by variable_get in settings.php.  It is
not the preferred method of handling values that you expect to change
during a page load or between page loads on a site. 

Conf_init() in my inspection of the source code on drupal_api
initializes conf to an array() not a string. Where do you see this
behavior? 

Dave

________________________________

From: support-bounces at drupal.org [mailto:support-bounces at drupal.org] On
Behalf Of Scott Matthews
Sent: Tuesday, January 29, 2008 8:19 AM
To: support at drupal.org
Subject: Re: [support] Issues with initializing Variables on startup..

I don't believe you fully understood me.

First off, variable_get does NOT retrieve from the database.  if you
look in the code it ONLY retrieves from that $conf variable that
variable_set stores the variable in when it sets to the database.  If,
as you suggest David, it really should retrieve from the database then
it is not working as defined.

function variable_get($name, $default) {

  global $conf;

  return isset($conf[$name]) ? $conf[$name] : $default;

}

Second, according to the comments in the settings.php, you can initially
override any variables stored in the database in the settings.php file
by setting the same variable that variable_get and variable_set uses:

/**

 * Variable overrides:

 *

 * To override specific entries in the 'variable' table for this site,

 * set them here. You usually don't need to use this feature. This is

 * useful in a configuration file for a vhost or directory, rather than

 * the default settings.php. Any configuration setting from the
'variable'

 * table can be given a new value.

 *

 * Remove the leading hash signs to enable.

 *

/# $conf = array(

#   'site_name' => 'My Drupal site',

#   'theme_default' => 'minnelli',

#   'anonymous' => 'Visitor',

# );

Scott Matthews

Senior Developer

(w) 617-227-1855 x164

(m) 617-710-8430

(f) 617-224-5388

smatthews at optaros.com

On Jan 29, 2008, at 11:04 AM, Metzler, David wrote:

I think you're confusing two completely independent constructs.  

Variable_get and variable_set are used to store system wide settings
that should persist in the database.  They are never (to my knowledge)
instantiated as PHP variables. The caching structure is meant to reduce
the number of database hits involved in loading variables, and should
not generally be accessed directly.  Multiple calls to variable_get
should leverage the cached variables as appropriate. 

The variables in settings.php can be used, you can define your own
global variables there, but if you want them to persist between page
loads you need to do that yourself.  IN your hooks you can reference
these variables after defining them as globals, but be careful with
namespace collisions.  I usually create a global variable that has the
same name as my module and store everying inside it (as an associative
array).  

Finally session variables can be used and will persist in the database
for the duration of a session.  

Hope that clarifies things.  It sounds like drupal is behaving as
designed here. 

Dave

________________________________

From: support-bounces at drupal.org [mailto:support-bounces at drupal.org] On
Behalf Of Scott Matthews
Sent: Tuesday, January 29, 2008 7:37 AM
To: support at drupal.org
Cc: Ron Trevarrow
Subject: [support] Issues with initializing Variables on startup..

I found what Appears to be a bug (or two) with initializing variables in
Drupal.

It is suggested that you can uncomment and set initial variable values
in settings.php with the $conf array.  In doing so, and not seeing my
variables set when retrieving using variable_get, I discovered that
conf_init(), when called to initialize the configure file path, it sets
$conf to a string.  I know that since it initializes settings.php within
the context it conceptually SHOULD reset it to a variable, but it
doesn't.   I proved this by changing the variable array name in
settings.php, variable_get, variable_set, variable_init and conf_init to
$config_vars and the values I initialized in settings.php were reflected
when my application later retrieved them using variable_get.

This bug is currently hindering the flexibility of an application that
I'm writing that will be deployed to different environments.  I
initially tried to set the variables in the 'variable' table of the
Database in order to retrieve them with variable_get but that method
only accesses the cached variables in $conf (or in my case,
$config_vars.  Is this on purpose?  I see that variable_set will not
only set the cached variable but will also set into the database.  This
seems to be a bug as well to me.  Can someone clarify this for me?

Scott Matthews

-- 

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