php - 在 X 段之后注入(inject)代码但避免使用表格

Question

我想在 X 段之后注入(inject)一些代码，这使用 php 很容易。

public function inject($text, $paragraph = 2) {

    $exploded = explode("</p>", $text);
    if (isset($exploded[$paragraph])) {
        $exploded[$paragraph] = '
            MYCODE
            ' . $exploded[$paragraph];

        return implode("</p>", $exploded);
    }
    return $text;
}

但是，我不想注入(inject)我的 $text在 <table> 里面，那么如何避免这种情况呢？

谢谢

Answer 1

我有时有点疯狂，有时我会选择懒惰的模式，但这次我想要一些朦胧的东西。

$input = 'test <table><p>wuuut</p><table><p>lolwut</p></table></table> <p>foo bar</p> test1 <p>baz qux</p> test3'; # Some input
$insertAfter = 2; # Insert after N p tags
$code = 'CODE'; # The code we want to insert

$regex = <<<'regex'
~
# let's define something
(?(DEFINE)
   (?P<table>                     # To match nested table tags
      <table\b[^>]*>
         (?:
            (?!</?table\b[^>]*>).
         |
            (?&table)
         )*
      </table\s*>
   )
   (?P<paragraph>                 # To match nested p tags
      <p\b[^>]*>
         (?:
            (?!</?p\b[^>]*>).
         |
            (?&paragraph)
         )*
      </p\s*>
   )
)
(?&table)(*SKIP)(*FAIL)           # Let's skip table tags
|
(?&paragraph)                     # And match p tags
~xsi
regex;

$output = preg_replace_callback($regex, function($m)use($insertAfter, $code){
    static $counter = 0; # A counter
    $counter++;
    if($counter === $insertAfter){ # Should I explain?
        return $m[0] . $code;
    }else{
        return $m[0];
    }
}, $input);

var_dump($output); # Let's see what we've got

Online regex demo <知识库> Online php demo

引用资料:

• Reference - What does this regex mean?
• What does the "[^][]" regex mean?
• Verbs that act after backtracking and failure
• Is there a way to define custom shorthands in regular expressions?