PHP escape unescaped quote marks

Question

I know I can use the following to replace " with \\":

str_replace('"', '\"', $string);

But if some quotemarks are already escaped the above code breaks things as it replaces \\" with \\ \\".

So is there any way I can search and replace " only and ignore \\"?

Answer 1

Try something like this:

preg_replace('/(?<!\\)"/', '\"', $data);

Honestly though, escaping in this way is ugly. And if you need this, you are already doing something wrong.

You should highly consider refactoring your code to use proper escaping functions for what you are trying to achieve and so you won't need to worry about double-escaping :)