How can I remove the NULL character from string - php

Question

I have a PHP variable that contains a string which represents an XML structure. This string contains ilegal characters that dont let me build a new SimpleXMLElement object from the string. I dont have a way to ask the source of the content to modify their response, so I need to execute some cleaning on this string before I create a SimpleXMLElement object.
I believe the character causing the problem is a  (0x00 (00) HEX) character, and its located within one of the Text Nodes of this string XML.
What is the best way to remove this character or other characters that could break the SimpleXMLElement object.

Answer 1

$text = str_replace("\0", "", $text);
will replace all null characters in the $text string. You can also supply arrays for the first two arguments, if you want to do multiple replacements.

Answer 2

trim() will also remove null characters, from either end of the source string (but not within).
$text = trim($text);
I've found this useful for socket server communication, especially when passing JSON around, as a null character causes json_decode() to return null.

Answer 3

While it's probably not the primary target of your question, please have a look at PHP's filter functions: http://www.php.net/manual/en/intro.filter.php
Filter functions validate and sanitize values. Form the PHP site:
$a = 'joe#example.org';
$b = 'bogus - at - example dot org';
$c = '(bogus#example.org)';
$sanitized_a = filter_var($a, FILTER_SANITIZE_EMAIL);
if (filter_var($sanitized_a, FILTER_VALIDATE_EMAIL)) {
echo "This (a) sanitized email address is considered valid.\n";
}
$sanitized_b = filter_var($b, FILTER_SANITIZE_EMAIL);
if (filter_var($sanitized_b, FILTER_VALIDATE_EMAIL)) {
echo "This sanitized email address is considered valid.";
} else {
echo "This (b) sanitized email address is considered invalid.\n";
}
$sanitized_c = filter_var($c, FILTER_SANITIZE_EMAIL);
if (filter_var($sanitized_c, FILTER_VALIDATE_EMAIL)) {
echo "This (c) sanitized email address is considered valid.\n";
echo "Before: $c\n";
echo "After: $sanitized_c\n";
}
Result:
This (a) sanitized email address is considered valid.
This (b) sanitized email address is considered invalid.
This (C) sanitized email address is considered valid.
Before: (bogus#example.org)
After: bogus#example.org