Question

I am trying to take a pic upload from a mobile device to a server. We are building with PhoneGap (Javascript), so we are having turn it into a string in order to send it to the server. I am having problems once I receive it, to turn it back into a readable image file.
Simply put, I need to take a string and a file name sent to me, decode it, convert it into a .png, then crop it into a circular image.

This is what I have going on currently

if (isset($_POST['file'])) 
{
    //Result variable
    $result = false;

    $pic = base64_decode($_POST['file']);
    $filename = $_POST['filename'];

    if (strlen($pic) > 9 )
    {
        $fh = fopen("/var/www/pics/events/".$filename, 'w') or die("can't open file");
        fwrite($fh, $pic);
        fclose($fh);
    }
}

I think I can get the rest of the code to work if I can figure out what I am doing wrong here that makes it not save properly as a image file? The file uploads correctly, but it stores with out an extension, and when I point to it in my browser, it comes up like it is supposed to be an image file, but never displays the image. That little broken picture icon with the colored shapes is what I get when I direct to it’s location.

Do I need to be aware of what image type is being sent during this process at all? How is it knowing if it is a .gif, .jpg/jpeg, .png, etc…?

Thanks in advance for any help!

Nathan

Answer 1

For Security reasons you should sanitize the file name to prevent directory traversal.

On a brighter note, make sure the file is saved with the proper extension; if you are already saving with the correct extension you could have an encoding issue from the app.

If neither of the previous possibilities are the case make sure that your String Size does not exceed the maximum POST size limit in your php.ini; if that is the case increase the size limit.