Topic: preg_replace help

[Swift-R]

Can someone explain what is wrong with this code?

$string = "blabla <'bl'a'> hello";
$result = preg_replace( "#<'([^'>]\S+)'>#", "'" . $this->escape_string( "$1" ) . "'", $string );

What this is supposed to do is to pick the text inside <' and '> and do a mysql_real_escape_string ($this->escape_string) to that text.
It is displaying the $string correctly, without the < and > but escape_string isn't working. It's supposed to return blabla 'bl\'a' hello instead of blabla 'bl'a' hello.

I have also tried to use the function strtoupper instead of $this->escape_string but it is still not working.

Any ideas?

[salathe]

You can't call preg_replace like that (and have it do what you're expecting). The replacement string will effectively be '$1' which of course just wraps the matched value in single quotes.

Instead, you should use a callback function with preg_replace_callback() like:

// The match gets fed into this function which returns the replacement string
public function escape_and_quote_match($match) {

return "'" . $this->escape_string($match[1]) . "'";
}

// How to call preg_replace_callback
$result = preg_replace("#<'([^'>]\S+)'>#", array($this, 'escape_and_quote_match'), $string);

[Swift-R]

You can't call preg_replace like that (and have it do what you're expecting). The replacement string will effectively be '$1' which of course just wraps the matched value in single quotes.

Instead, you should use a callback function with preg_replace_callback() like:

// The match gets fed into this function which returns the replacement string
public function escape_and_quote_match($match) {

return "'" . $this->escape_string($match[1]) . "'";
}

// How to call preg_replace_callback
$result = preg_replace("#<'([^'>]\S+)'>#", array($this, 'escape_and_quote_match'), $string);

Thank you!

$result = preg_replace_callback( "#<'([^'>]\S+)'>#", create_function( '$matches', 'return strtoupper($matches[1]);' ), $string);

But if I use $this->escape_string($matches[1]); it returns this error:

Using $this when not in object context in ... : runtime-created function on line 1

Guess I'll have to use your example.

[salathe]

That's correct, anonymous functions (those created using create_function) do not belong to a class/object so $this is meaningless in that case.