Best way to automatically remove comments from PHP code

benlumley_39161 0
Viewed 51843

What’s the best way to remove comments from a PHP file?

I want to do something similar to strip-whitespace() - but it shouldn't remove the line breaks as well.

For example,

I want this:

<?PHP
// something
if ($whatsit) {
    do_something(); # we do something here
    echo '<html>Some embedded HTML</html>';
}
/* another long
comment
*/
some_more_code();
?>

to become:

<?PHP
if ($whatsit) {
    do_something();
    echo '<html>Some embedded HTML</html>';
}
some_more_code();
?>

(Although if the empty lines remain where comments are removed, that wouldn't be OK.)

It may not be possible, because of the requirement to preserve embedded HTML - that’s what’s tripped up the things that have come up on Google.

strip comments php
14 Answers

I'd use tokenizer. Here's my solution. It should work on both PHP 4 and 5:

$fileStr = file_get_contents('path/to/file');
$newStr  = '';

$commentTokens = array(T_COMMENT);
    
if (defined('T_DOC_COMMENT')) {
    $commentTokens[] = T_DOC_COMMENT; // PHP 5
}

if (defined('T_ML_COMMENT')) {
    $commentTokens[] = T_ML_COMMENT;  // PHP 4
}

$tokens = token_get_all($fileStr);

foreach ($tokens as $token) {    
    if (is_array($token)) {
        if (in_array($token[0], $commentTokens)) {
            continue;
        }
        
        $token = $token[1];
    }

    $newStr .= $token;
}

echo $newStr;
Ionut_G_Stan_588080

Use php -w <sourcefile> to generate a file stripped of comments and whitespace, and then use a beautifier like PHP_Beautifier to reformat for readability.

Paul_Dixon_65210 
$fileStr = file_get_contents('file.php');
foreach (token_get_all($fileStr) as $token ) {
    if ($token[0] != T_COMMENT) {
        continue;
    }
    $fileStr = str_replace($token[1], '', $fileStr);
}

echo $fileStr;
tom_222240

Following upon the accepted answer, I needed to preserve the line numbers of the file too, so here is a variation of the accepted answer:

    /**
     * Removes the php comments from the given valid php string, and returns the result.
     *
     * Note: a valid php string must start with <?php.
     *
     * If the preserveWhiteSpace option is true, it will replace the comments with some whitespaces, so that
     * the line numbers are preserved.
     *
     *
     * @param string $str
     * @param bool $preserveWhiteSpace
     * @return string
     */
    function removePhpComments(string $str, bool $preserveWhiteSpace = true): string
    {
        $commentTokens = [
            \T_COMMENT,
            \T_DOC_COMMENT,
        ];
        $tokens = token_get_all($str);


        if (true === $preserveWhiteSpace) {
            $lines = explode(PHP_EOL, $str);
        }


        $s = '';
        foreach ($tokens as $token) {
            if (is_array($token)) {
                if (in_array($token[0], $commentTokens)) {
                    if (true === $preserveWhiteSpace) {
                        $comment = $token[1];
                        $lineNb = $token[2];
                        $firstLine = $lines[$lineNb - 1];
                        $p = explode(PHP_EOL, $comment);
                        $nbLineComments = count($p);
                        if ($nbLineComments < 1) {
                            $nbLineComments = 1;
                        }
                        $firstCommentLine = array_shift($p);

                        $isStandAlone = (trim($firstLine) === trim($firstCommentLine));

                        if (false === $isStandAlone) {
                            if (2 === $nbLineComments) {
                                $s .= PHP_EOL;
                            }

                            continue; // Just remove inline comments
                        }

                        // Stand-alone case
                        $s .= str_repeat(PHP_EOL, $nbLineComments - 1);
                    }
                    continue;
                }
                $token = $token[1];
            }

            $s .= $token;
        }
        return $s;
    }

Note: this is for PHP 7+ (I didn't care about backward compatibility with older PHP versions).

user_4050420

In 2019 it could work like this:

<?php
/*   hi there !!!
here are the comments */
//another try

echo removecomments('index.php');

/*   hi there !!!
here are the comments */
//another try
function removecomments($f){
    $w=Array(';','{','}');
    $ts = token_get_all(php_strip_whitespace($f));
    $s='';
    foreach($ts as $t){
        if(is_array($t)){
            $s .=$t[1];
        }else{
            $s .=$t;
            if( in_array($t,$w) ) $s.=chr(13).chr(10);
        }
    }

    return $s;
}

?>

If you want to see the results, just let's run it first in XAMPP, and then you get a blank page, but if you right click and click on view source, you get your PHP script ... it's loading itself and it's removing all comments and also tabs.

I prefer this solution too, because I use it to speed up my framework one file engine "m.php" and after php_strip_whitespace, all source without this script I observe is slowest: I did 10 benchmarks, and then I calculate the math average (I think PHP 7 is restoring back the missing cr_lf's when it is parsing or it is taking a while when these are missing).

Admin1

The catch is that a less robust matching algorithm (simple regex, for instance) will start stripping here when it clearly shouldn't:

if (preg_match('#^/*' . $this->index . '#', $this->permalink_structure)) {

It might not affect your code, but eventually someone will get bit by your script. So you will have to use a utility that understands more of the language than you might otherwise expect.

Adam_Davis_29150
user_109918170
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