Determine what namespace the function was called in

Question

I was wondering if it was possible to determine what the current namespace was when the function was being called. I have this function declaration:

Answer 1

If you were using closures instead of static functions you can always ask the reflection API

namespace A;
$closure = function($word = 'hello')
{
    return $word;
};

...

$r = new ReflectionFunction($closure);
print $r->getNamespaceName();

Answer 2

i don't know if i'm missing something, but with this:

http://php.net/manual/en/reflectionclass.getnamespacename.php, i think that you can get namespace of the object you are using.

Answer 3

What you are looking for is : ReflectionFunctionAbstract::getNamespaceName

If you want to know where you're coming from debug_backtrace() is your friend.

The following should solve your puzzle:

function backtrace_namespace() 
{
    $trace = array();
    $functions = array_map(
        function ($v) {
            return $v['function'];
        },
        debug_backtrace()
    );
    foreach ($functions as $func) {
        $f = new ReflectionFunction($func);
        $trace[] = array(
            'function' => $func, 
            'namespace' =>  $f->getNamespaceName()
        );
    }
    return $trace;
}

Just call it from anywhere to see the backtrace. I modified your "procedural" code file as follows:

namespace Foo;

function bar () 
{
    var_export(backtrace_namespace());
}

/** The unasked question: We need to use the fully qualified name currently. */
function go() 
{
    \Site\Action\add('hookname', 'Foo\\bar');
}

go();

The Result from including this file will be the following on stdout:

array (
    0 =>
    array (
        'function' => 'backtrace_namespace',
        'namespace' => '',
    ),
    1 =>
    array (
        'function' => 'Foo\\bar',
        'namespace' => 'Foo',
    ),
    2 =>
    array (
        'function' => 'call_user_func',
        'namespace' => '',
    ),
    3 =>
    array (
        'function' => 'Site\\Action\\add',
        'namespace' => 'Site\\Action',
    ),
    4 =>
    array (
        'function' => 'Foo\\go',
        'namespace' => 'Foo',
    ),
)

Now for bonus points the answer to the hidden question:

How do I resolve the calling namespace to avoid using fully qualified function name as argument?

The following will allow you to call the function as you intended:

 Site\Action\add('hookname', 'bar');

Without getting the dreaded:

Warning: call_user_func() expects parameter 1 to be a valid callback, function 'bar' not found or invalid function name

So before you redesign try this on for size:

namespace Site\Action;

function add($hook, $function) 
{
    $trace = backtrace_namespace();
    $prev = (object) end($trace);

    $function = "$prev->namespace\\$function";

    if (is_callable($function))
        call_user_func($function);
}

I see no reason why debug_backtrace should not be used, this is what it is there for.

nJoy!