2

I find myself in the situation where I need to call a PHP function stored as a string from another PHP function.

<?php
$phpcodestring = "<?php echo 'Hello World!' ?>";
echo $phpcodestring;
?>

How can I get Hello World to render to screen with the above structure?

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6 Answers 6

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2

Back up a few steps - why do you need to do that?

99.9% of the time there is a better way than eval().

Or you could use create_function() which internally uses something like eval() so isn't much better, especially when you are not defining the function body directly with a string literal so you can be sure there and then there is nothing potentially dangerous.

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3 Comments

I have PHP piece of code that exists in a WordPress theme options panel setting. I need to get this code into the interpreter and make it run.
@trnsrmr Ah WordPress, I should have known! Just hope there are no SQL injection holes.
I'd rather not doing anything that makes my theme more un secure. Will try and figure out a better way.
0

You can use the infamous eval() if you thoroughly trust the source of the string. How the hell did you find yourself in that situation?

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The PHP code I'm trying to run is stored as a string in a WordPress theme options panel.
0

Sounds like a case of eval().

eval("echo 'Hello world!';");

You should always consider whether it's a good idea or not, though. Security considerations of eval() can be daunting.

G

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3 Comments

I'd rather not create any security issues.
You just need to handle the inputs to eval carefully. It really, really is a last resort type of approach, though. Perhaps save the options panel setting as a file and include it?
Hmmm, will try and think of a better way.
0

You can use the eval() function: http://php.net/manual/en/function.eval.php

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0

eval($phpcodestring);

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2 Comments

This did not work. Here is my code: <?php $phpcodestring = "<?php echo 'Hello World!' ?>"; echo eval($phpcodestring); ?> Here is the error: Parse error: syntax error, unexpected '<' in /Users/jc/Sites/test.php(3) : eval()'d code on line 1
you musst strip the <?php and ?> in the code string and attach a semicolon at the end of the string like $phpcodestring = "echo 'Hello World!';";
0

An alternative approach would be to use create_function method, which is a poor implementation of lambda-style functions in PHP.

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2 Comments

Doesn't create_function have the same security flaws as eval?
@trnsfrmr it is, but the solution is a bit more 'elegant' IMO

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