How to get a unique name for each uploaded file using uploadify

I am uploading files using jQuery uploadify plugin. All files are uploaded into same directory. When I try to upload a file twice, it give开发者_如何学Go me following error.

filename.gif (4.3KB) - IO Error

I want to upload a file with unique name every time. There are many other users uploading files in same directory. So there is a chance that two users share same file name. How can I avoid overwritten.

My Code:

$('.SingleFileUpload').uploadify({
        'uploader'  : '/uploadify/uploadify.swf',
        'script'    : '/uploadify/uploadify.php',
        'cancelImg' : '/uploadify/cancel.png',
        'folder'    : '/uploads',
        'auto'      : true,
        'queueID'   : 'fileQueue',
        'removeCompleted':false,
        'onComplete'  : function(event, ID, fileObj, response, data) {
                            $(event.target).closest('form').append( '<input type="hidden" name="uploaded_file" value="' + response + '">' );
                        }
      });

To start off, reject duplicate file names:

$targetFolder = '/uploads'; // Relative to the root

if (!empty($_FILES)) {
    $tempFile = $_FILES['Filedata']['tmp_name'];
    $targetPath = $_SERVER['DOCUMENT_ROOT'] . $targetFolder;
    $targetFile = rtrim($targetPath,'/') . $_FILES['Filedata']['name'];

    // Validate the file type
    $fileTypes = array('jpg','jpeg','gif','png'); // File extensions
    $fileParts = pathinfo($_FILES['Filedata']['name']);

    if (in_array($fileParts['extension'],$fileTypes)) {
        if (file_exists($targetFile)){
            echo 'File does already exist, choose another name!';
        }
        else {
            move_uploaded_file($tempFile,$targetFile);
            echo '1';
        }
    } else {
        echo 'Invalid file type.';
    }
}
?>

You can prefix all of your file names by the ID of the user + an underscore (or any character to separate the ID from the file name, to avoid UID1 + 2file == UID12 + file.

Instead of forcing the user to choose another name, you can also implement an automated name change: Either by adding a prefix and/or postfix, or by calculating the hash of the file. The last option also prevents duplicate files (same name, same contents) from appearing at the server.

I don't think using javascript is good or safe for this, one method I use is to name each file by calculate its SHA1 on server side.

I'm duplicating the filename and adding the copynr at the end. like: filename(2) filename(3) filename(4) etc.

$('#upload').uploadify({
        'uploader'       : 'resources/plugins/uploadify/uploadify.swf',
        'script'         : 'resources/plugins/uploadify/uploadify.php',
        'cancelImg'      : 'resources/plugins/uploadify/cancel.png',
        'folder'         : 'uploads/',
        'auto'           : true,
        'multi'          : false,
        'fileDesc'       : '*.jpg;*.jpeg;*.png;*.gif;',
        'fileExt'        : '*.jpg;*.jpeg;*.png;*.gif;',
        onComplete: function (evt, queueID, fileObj, response, data){
            alert(response); // = uploaded filename
        }

just the uploadify JS part (not using the check method!) Now the uploadify.php part

if (!empty($_FILES)) {
$tempFile = $_FILES['Filedata']['tmp_name'];
    $ext = '.'.pathinfo($_FILES['Filedata']['name'], PATHINFO_EXTENSION);
    $filename = substr($_FILES['Filedata']['name'],0,-strlen($ext));
$targetPath = $_SERVER['DOCUMENT_ROOT'] . $_REQUEST['folder'] . '/';
$targetFile =  str_replace('//','/',$targetPath) . $filename . $ext;

    while(file_exists($targetFile)){
        preg_match('/\([0-9]{1,}\)$/', $filename,$matches);
        if(!empty($matches)){
            preg_match('/[0-9]{1,}/', $matches[0],$nr);
            $filename = substr($filename,0,-strlen($matches[0])) . '('.(((int)$nr[0])+1).')';
        }else
            $filename .= '(2)';
        $targetFile = str_replace('//','/',$targetPath) .$filename . $ext;
    }

if(!is_dir($targetPath)) mkdir(str_replace('//','/',$targetPath), 0755, true);

move_uploaded_file($tempFile,$targetFile);
echo $filename.$ext;}

HTH