Post meta escaping

gistfile1.txt

$str1 = '\\"';

update_post_meta($post->ID, "test", $str1);
$str2 = get_post_meta($post->ID, "test", true);

echo "$str1<br>$str2";

/*

Result:
\"
"

More realistic use case...
Input: {"key":"value with \"quotes\" in the content."}
Output: {"key":"value with "quotes" in the content."}

The problem is that the output has returned something different than the input, making JSON data unparsable.

Solution from [wp-hackers] list: serialize the string on the way in, unserialize on the way out. <sigh>

*/