我使用filter_input的方式有什么问题？ [重复]

Question

This question already has an answer here:

• PHP's filter_input() strips $_SERVER data on external host, but works on localhost 2 answers

I am told that I should use filter_input rather than accessing $_SERVER directly

So I made this simple 2 line of code

    echo "filter:input " . filter_input(INPUT_SERVER,'REMOTE_ADDR');
    echo "SERVER:" .$_SERVER['REMOTE_ADDR'] ; 

Very simple. I expect they both produce the exact same thing.

This is what I got

filter:input SERVER:202.80.212.17

Clearly filter_input(INPUT_SERVER,'REMOTE_ADDR') produces empty string.

Why?

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Answer 1

It has been a bug in older versions of php. You can either use

echo "filter:input " . filter_input(INPUT_ENV, 'REMOTE_ADDR', FILTER_VALIDATE_IP);

Or use

echo "filter:input " . filter_input($_SERVER['REMOTE_ADDR']);