File input validation

Question

You have a web page with a form that has an input field of type file. You have another web page that expects the data from the first page.

In the second page you need to check whether a file has been sent.

How do you do that?

I've been using the following statement but I'm not sure about it:

$_FILES["file"]["tmp_name"] == ""

Answer 1

Try array_key_exists("file", $_FILES)

Answer 2

I don't work with PHP file uploads often, but is there any reason that:

isset($_FILES['file'])

won't do the trick?

Answer 3

• http://www.w3schools.com/php/php_file_upload.asp

  <?php
  if ($_FILES["file"]["error"] > 0)
  {
      echo "Error: " . $_FILES["file"]["error"] . "<br />";
  }
  else
  {
      echo "Upload: " . $_FILES["file"]["name"] . "<br />";
      echo "Type: " . $_FILES["file"]["type"] . "<br />";
      echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />";
      echo "Stored in: " . $_FILES["file"]["tmp_name"];
  }
  ?>
  

Answer 4

Or you could just check if $_FILES is empty.

if(empty($_FILES))
{
return false; // or make something else
}