How do I make Opera upload files like other browsers?

Question

When uploading one file using <input type="file" /> in Opera, it works as expected. That is, you find the expected file data in $_FILES in PHP server side.

However, when I try to upload several files at once using Opera, by setting <input type="file" min="1" max="999" /> then all the files' contents are glued together in one long string and sent as POST data. All the files in this string are separated by headers such as this:

------------94QV8HRqBwta8NY4L2WH0r
Content-Disposition: form-data; name="file[]"; filename="xxx1069225496.xml"
Content-Type: text/xml

<?xml>
...

Opera follows the Webforms 2.0 standard, I know. But is there a simple way to make Opera send multiple files in the same fashion other browsers do, or will I have to write an interpreter to get files just from Opera?

Thanks for any help. Below is the HTML I'm currently using.

---

<div id="filearea">
    <input type="file" min="1" max="6000" accept="text/xml" name="file[]" style="padding: 1px; margin: 2px 0px;" />
</div>

---

This is how the var_dump of $_POST looks (I've erased any actual XML data, taking up space)

array(1) {
  ["file"]=>
  array(1) {
    [0]=>
    string(4209) "------------94QV8HRqBwta8NY4L2WH0r
Content-Disposition: form-data; name="file[]"; filename="1219854274.xml"
Content-Type: text/xml

<?xml version="1.0"?>
...

------------94QV8HRqBwta8NY4L2WH0r
Content-Disposition: form-data; name="file[]"; filename="xxx1069225496.xml"
Content-Type: text/xml

<?xml version="1.0"?>
...

------------94QV8HRqBwta8NY4L2WH0r
Content-Disposition: form-data; name="file[]"; filename="xxx1111008062.xml"
Content-Type: text/xml

<?xml version="1.0"?>
...

------------94QV8HRqBwta8NY4L2WH0r
Content-Disposition: form-data; name="file[]"; filename="1219854274.xml"
Content-Type: text/xml

<?xml version="1.0"?>
...
    "
  }
}

Answer 1

I just checked a PHP bug report, and it claimed that this works in Opera:

<input type="file" name="file" min="1" max="999" />

But that this does not:

<input type="file" name="file[]" min="1" max="999" />

Edit: After testing this, I believe the PHP person who marked the bug as bogus didn't know what he was talking about... I cannot get either way to work natively with PHP.

As far as I can tell, PHP does not support Opera's 'mixed' file uploads. This is not a bug on Opera's part, as they are implementing it per the RFC's specification. I believe the other browsers simply upload the files as if there were multiple input elements. You could easily add support for this by checking the _POST array:

   $file = $_POST['file'][0];

   while (preg_match('/^(-+[A-Za-z0-9]+)\s+/', $file, $matches))
   {
      $id = $matches[1];

      $i = strlen($matches[0]);
      $body = false;
      $headers = array();
      while (($j = strpos($file, "\n", $i)) !== false)
      {
         $line = substr($file, $i, $j - $i);
         $i = $j + 1;
         if (trim($line) == '')
         {
            $body = true;
            break;
         }

         list($key, $val) = explode(':', trim($line), 2);
         $headers[$key] = trim($val);
      }
      if (!$body) break;

      $j = strpos($file, $id, $i);

      $data = substr($file, $i, $j-$i);
      echo $data."<HR>"; // also check $headers

      $file = substr($file, $j);
   }

There may be some off-by one errors in the above code.