File input validation

You have a web page with a form that has an input开发者_Python百科 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"] == ""

• 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"];
  }
  ?>
  

Try array_key_exists("file", $_FILES)

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

isset($_FILES['file'])

won't do the trick?

Or you could just check if $_FILES is empty.

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