php isset do you need it in a form check?

Question

I trying to understand if a isset is required during form processing when i check $_REQUEST["input_name"] if no value is passed it doesn't cry about it and php doesn't throw out an error if you are trying to access a array item which doesn't exist....i can use if($_REQUEST["input_name"]).. what about "empty" even in those cases i can use if()

THnks

Answer 1

I wouldn't recommend using the $_REQUEST superglobal for capturing form input, unless you're testing a form. Use $_GET or $_POST instead, unless you have a really good reason.

Also, isset() and array_key_exists() both do the same trick with regard to array keys, although array_key_exists() is clearer in an arrays context.

I recommend using:

error_reporting(E_ALL); //E_ALL - All errors and warnings

within your development environment, as that can expose where better practices might be applied, such failure to declare variables before they are used, etc.

Answer 2

There are different type of error levels. Checking a variable that is not set only throws a notice. Your error reporting is probably set to ignore those. It is best practice to always use isset when you want to check if a variable has been set, although it does have its gotchas .

Doing only what you are doing above, for example, if $_REQUEST["input_name"] is the string "0", it will evaluate to false. Also it is not a good idea to use $_REQUEST to begin with, as it can be affected by stuff like cookies and such and it's usually a code smell for bad architecture.

Answer 3

using $_REQUEST is pretty much a hack. You should be using $_POST or $_GET (depending on what you are doing) and you should use isset().

Every book I've read on PHP seems to say that.

Answer 4

Generally, at least for testing, set error reporting to E_ALL (all errors and warnings) either in your php.ini or in code using error_reporting(E_ALL); ( Look into adding E_STRICT too.) Better to get an obvious notice about an error up front, than to have something subtle go wrong that you don't catch till later.

Avoid using $_REQUEST, which is too vague (it includes GET, POST AND cookie values), and use the $_POST or $_GET if those are what you really mean, and do check with isset($_POST["input_name"])

The short answer is "Yes." :)

Answer 5

if($_REQUEST["input_name"])

如果“ input_name”不存在，将引发通知（错误），因此建议使用isset（）。