Detecting Google Bot to hide content - dangerous?

Question

I've been looking into various ways to reduce duplicate content on a client's website.

One method I've come across is using some code to check whether the client is a certain bot, or not. Using this information one can choose to display information to the client, or not.

Would this method be dangerous to use with Google for any reason?

Here's the code (PHP), for information:

if(strstr(strtolower($_SERVER['HTTP_USER_AGENT']), "googlebot"))

Answer 1

Please explain what you mean by "dangerous".

You are not disallowed to block web crawlers from going through your website if that is your intention AFAIK, you could easily do this with "robots.txt" instead of PHP implementation though.

However, if by "dangerous" you mean security exploits, then of course there is the whole deal with user agent spoofing, so I wouldn't advise to say give away more data than you would want just basing it on what user agent the request is hiding behind because that can be faked.