How to make php function as string do real function?

Question

lets assume that i have function named printuser()

now if i have string like

$myFunction = 'printuser()';

how i can run this string as function ? so it should do the printuser() function

What problem are you trying to solve? There is probably a better way. — Andy Lester
– Andy Lester, Commented Nov 26, 2012 at 18:31

Madara's Ghost · Accepted Answer · 2012-11-26 18:18:12Z

3

Have a look at call_user_func. You'll need to change your string a little (no brackets).

answered Nov 26, 2012 at 18:18

Madara's Ghost

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1 Comment

user895378 Over a year ago

+1 call_user_func makes it explicit what you're trying to do in your code ... which is much better for poor Joe Programmer who has to maintain it down the road and doesn't inappropriately expose you to the dangers of eval.

cHao · Accepted Answer · 2014-05-16 19:30:19Z

1

If you just want $myFunction to specify which function to run, you can do something like

$myFunction = 'printuser';
$myFunction();

This is called a "variable function", and is slightly less dangerous than eval. (You can call any existing function, but you can't run arbitrary code.)

Be warned, though: if printuser doesn't exist, the script will die. You might consider checking for the function's existence before calling it.

$myFunction = 'printuser';
if (function_exists($myFunction))
    $myFunction();
else
    throw new BadFunctionCallException("Function '$myFunction' doesn't exist");

Replace the throw with whatever you want to do if the function isn't there. That's just an example.

edited May 16, 2014 at 19:30

answered Nov 26, 2012 at 18:19

cHao

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1 Comment

Rasha Sharif Over a year ago

Wow! it is great way to do it :)

ceejayoz · Accepted Answer · 2012-11-26 18:17:02Z

1

Use eval.
You almost never ever ever should do this. There's almost always a better, safer, more secure way.

answered Nov 26, 2012 at 18:17

ceejayoz

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ceejayoz Over a year ago

@MadaraUchiha Hence the "don't do this" note.

Baba · Accepted Answer · 2012-11-26 18:26:36Z

0

You can try

$myFunction = 'printuser()';
# Remove brakets
$myFunction = rtrim($myFunction, "()");
# Call Function Directly
$myFunction();

For validation you can use is_callable

is_callable($myFunction) and $myFunction();

Simple Demo

edited Nov 26, 2012 at 18:26

answered Nov 26, 2012 at 18:19

Baba

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Comments

Repox · Accepted Answer · 2012-11-26 18:29:09Z

0

A suggestion with a fail safe:

$function = str_replace("()", "", $input);
if( function_exists($function))
{
  $function();
}
else
{
  // ignore or show an error
}

answered Nov 26, 2012 at 18:29

Repox

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