How to check if a function is public or protected in PHP

Question

I am building an API where the user requests a 'command', which is passed into a class. Assuming the command matches a PUBLIC function, it will execute successfully. If the command matches a PROTECTED function, it needs to throw an error.

The idea is that functions can be disabled by changing them from PUBLIC to PROTECTED, rather than renaming them or removing them.

I currently do this, but it doesn't matter if the command is public or protected.

<?php
/**
 * Look for Command method
 */
$sMethod = "{$sCommand}Command";
if (method_exists($this, $sMethod))
{
    /**
     * Run the command
     */
    return $this->$sMethod($aParameters);
}

score 71 · Accepted Answer · answered Nov 12 '10 at 01:42

71

Simply use ReflectionMethod:

/**
 * Look for Command method
 */
if (method_exists($this, $sMethod))
{
    $reflection = new ReflectionMethod($this, $sMethod);
    if (!$reflection->isPublic()) {
        throw new RuntimeException("The called method is not public.");
    }
    /**
     * Run the command
     */
    return $this->$sMethod($aParameters);
}

answered Nov 12 '10 at 01:42

meze

14,975
4
47
52

I was going for this one, but you came before me :) – David Conde Nov 12 '10 at 01:45

score 12 · Answer 2 · answered Nov 12 '10 at 01:47

12

You can use the is_callable function to determine if the protection level should limit you: Example:

<?php
class FooBar {
    protected function Foo() { return; }
    public function Bar() { return; }
}

$foo = new FooBar();

var_dump(is_callable(array($foo, 'Foo')));
var_dump(is_callable(array($foo, 'Bar')));

answered Nov 12 '10 at 01:47

rhollencamp

533
4
13

9

I don't think is_callable works when I am calling from inside the same class (so protected methods ARE callable). – Stephen RC Nov 12 '10 at 02:03
1

you are correct - is_callable takes the current scope into consideration – rhollencamp Nov 13 '10 at 01:32
An example of how `is_callable()` returns different results depending on where the function is called: https://3v4l.org/fLaYN – dearsina Apr 07 '19 at 10:58

score 4 · Answer 3 · answered Jan 12 '17 at 22:27

Though you can not differentiate if the method is private or protected, you can test if public versus not using an external method using is_callable. I made a comparison with "meze" answer.

So:

function testIfCallable($object, $method) {
    return is_callable(array($object, $method));
}

function testIfCallable2($object, $method) {
    if (method_exists($object, $method))
    {
        $reflection = new ReflectionMethod($object, $method);
        return $reflection->isPublic();
    }

    return false;
}

class Test {

    private function privateMethod() {

    }

    protected function protectedMethod() {

    }

    public function publicMethod() {

    }

    public function testAccessibility() {
        if (testIfCallable($this, 'privateMethod')) echo "YYY<br>"; else echo 'NNN<br>';
        if (testIfCallable($this, 'protectedMethod')) echo "YYY<br>"; else echo 'NNN<br>';
        if (testIfCallable($this, 'publicMethod')) echo "YYY<br>"; else echo 'NNN<br>';
    }

    public function testAccessibility2() {
        if (testIfCallable2($this, 'privateMethod')) echo "YYY<br>"; else echo 'NNN<br>';
        if (testIfCallable2($this, 'protectedMethod')) echo "YYY<br>"; else echo 'NNN<br>';
        if (testIfCallable2($this, 'publicMethod')) echo "YYY<br>"; else echo 'NNN<br>';
    }       

    public function testSpeedAccessibility() {
        return $results = [
                testIfCallable($this, 'privateMethod'),
                testIfCallable($this, 'protectedMethod'),
                testIfCallable($this, 'publicMethod')
        ];
    }

    public function testSpeedAccesibility2() {
        return $results = [
                testIfCallable2($this, 'privateMethod'),
                testIfCallable2($this, 'protectedMethod'),
                testIfCallable2($this, 'publicMethod')
        ];
    }
}

The method testIfCallable shall be included in a Common class or something similar which you have in your own toolkit because global methods aren't recommended.

I use this in conjunction with the magic methods __get and __set to ensure a public "get/set" method exists.

Tests :

//Test functionality
$t = new Test();
$t->testAccessibility();
$t->testAccessibility2();

//Test speed
$start = microtime(true);
for($i = 0; $i < 10000; $i++) {
    $t->testSpeedAccessibility();
}
echo "Is Callable way: " . (microtime(true) - $start) . "ms<br>";

$start = microtime(true);
for($i = 0; $i < 10000; $i++) {
    $t->testSpeedAccesibility2();
}
echo "Reflection way: " . (microtime(true) - $start) . "ms<br>";

Outputs:

NNN
NNN
YYY
NNN
NNN
YYY
Is Callable way: 0.23506498336792ms
Reflection way: 0.45829010009766ms

Final thoughts

If you need to test between all the visibility possibilities, your only way to go is to use testIfCallable2, so the "meze"'s answer. Otherwise, my way is about twice faster. As your question was only between public or not, you could benefit using this. Saying that, if you don't use it often, the difference is not significant.

Keep in mind that the way you've set it up, with the functions calling `is_callable()` are on the "outside" of the class you're testing, will return different results from if your functions were "inside" the class: https://3v4l.org/fLaYN — dearsina, Apr 07 '19 at 10:57

How to check if a function is public or protected in PHP

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