is_real
I was recently trying to loop through some objects and convert them to arrays so that I could encode them to json strings.
I was running into issues when an element of one of my objects was a SoapClient. As it turns out, json_encode() doesn't like any resources to be passed to it. My simple fix was to use is_resource() to determine whether or not the variable I was looking at was a resource.
I quickly realized that is_resource() returns false for two out of the 3 resources that are typically in a SoapClient object. If the resource type is 'Unknown' according to var_dump() and get_resource_type(), is_resource() doesn't think that the variable is a resource!
My work around for this was to use get_resource_type() instead of is_resource(), but that function throws an error if the variable you're checking isn't a resource.
So how are you supposed to know when a variable is a resource if is_resource() is unreliable, and get_resource_type() gives errors if you don't pass it a resource?
I ended up doing something like this:
<?php
function isResource ($possibleResource) { return !is_null(@get_resource_type($possibleResource)); }
?>
The @ operator suppresses the errors thrown by get_resource_type() so it returns null if $possibleResource isn't a resource.
I spent way too long trying to figure this stuff out, so I hope this comment helps someone out if they run into the same problem I did.
is_resource
(PHP 4, PHP 5)
is_resource — Finds whether a variable is a resource
Parameters
-
var -
The variable being evaluated.
Return Values
Returns TRUE if var is a resource,
FALSE otherwise.
Examples
Example #1 is_resource() example
<?php
$db_link = @mysql_connect('localhost', 'mysql_user', 'mysql_pass');
if (!is_resource($db_link)) {
die('Can\'t connect : ' . mysql_error());
}
?>
add a note
User Contributed Notes
is_resource - [2 notes]
btleffler [AT] gmail [DOT] com ¶
2 years ago
tacomage at NOSPAM dot devilishly-deviant dot net ¶
8 years ago
Note that the use of is_resource isn't necessary in the example. mysql_connect (along with any other function that would return a resouce, I imagine) returns false on failure, so the same results could be obtained with:
<?php
$db_link = @mysql_connect('localhost', 'mysql_user', 'mysql_pass');
if (!$db_link) {
die('Can\'t connect : ' . mysql_error());
}
?>
Or even:
<?php
$db_link = @mysql_connect('localhost', 'mysql_user', 'mysql_pass')
or die('Can\'t connect : ' . mysql_error());
}
?>
You'd be more likely to use is_resource AFTER the initial conection, to make sure the variable you intend to use as a resource is, in fact, a connection resource. You might also use is_resource as a sanity-check prior to serializing an object, since resource variables can't be serialized.