[SOLVED] make uploaded file names unique?

[chrisuk]

I have been working on an upload script and it occurred to me that there would be a problem if someone tried to upload a file that already exists.

 

Instead of producing an error message telling the user to rename their file, that i should append something to the uploaded filename to make it unique.

 

I'd thought for the purposes of the system i am making (relatively low number of users) that a timestamp down to the second would be a sufficient measure to ensure that this problem does not occurr.

 

At the minute, my script is as follows:

 

<? 

$target_path = "../uploads/";

$target_path = $target_path . basename( $_FILES['uploadedfile']['name']); 

$_FILES['uploadedfile']['tmp_name'];  

if(move_uploaded_file($_FILES['uploadedfile']['tmp_name'], $target_path)) {
    echo '<a href="<server>/uploads/';
    echo basename( $_FILES['uploadedfile']['name']). '">Click here to download your file</a>';
} else{
    echo "There was an error uploading the file, please try again!";
}
  
?>

 

(i have replaced the actual url with <server> for the sake of this example.

 

How would i incorporate a timestamp into the filename before it was uploaded?

 

I tried this:

 

<? 

$target_path = "../uploads/";

$now = date("jmyGis");

$target_path = $target_path . basename( $_FILES['uploadedfile']['$now']['name']); 

$_FILES['uploadedfile']['tmp_name'];  

if(move_uploaded_file($_FILES['uploadedfile']['now']['tmp_name'], $target_path)) {
echo '<a href="<server>/uploads/';
    echo basename( $_FILES['uploadedfile']['$now']['name']). '">Click here to download your file</a>';
} else{
    echo "There was an error uploading the file, please try again!";
}
  
?>

 

but it failed.

 

Any ideas? or is there a better way to do this?

 

thanks

[papaface]

Your way wont work. You simply need to seperate the file extention and then re-apply it later.

 

e.g.:

 

<?php
list($the_file_bit, $extension) = explode('.', $_FILES["upload"]["name"]); //get extention

//then later
$random  = rand();
$tmpname = $_FILES["upload"]["tmp_name"];
$location = "files/" . $rand . "." . $extension;

move_uploaded_file($tmpname,$location);

?>

[chrisuk]

Thanks for your reply.

 

I'm unsure how to apply this to my code though?

 

Thanks

[papaface]

Should be:

<?php

$target_path = "../uploads/";

$now = date("jmyGis");

list($the_file_bit, $extension) = explode('.', $_FILES["uploadedfile"]["name"]); //get extention

$filename = $now . $extension;

$target_path = $target_path . $filename; 

if(move_uploaded_file($_FILES['uploadedfile']['tmp_name'], $target_path)) {
echo '<a href="<server>/uploads/';
    echo basename( $_FILES['uploadedfile']['$now']['name']). '">Click here to download your file</a>';
} else{
    echo "There was an error uploading the file, please try again!";
}
  
?>

[bwochinski]

Might want to add a check for "." in the filename, that could mess things a little...

 

( and can we please use date("U") for the timestamp?? lol )

[craygo]

explode won't work if some numnuts puts a period in the filename

 

I have had good success with strrchr

<?php
<?php
$file = $_FILES["upload"]["name"];
$tmpfile = $_FILES["upload"]["tmp_name"];
if(file_exists($file)){
$filename = substr($file,0,strrpos($file, "."));
$filename .= rand();
$extension = strrchr($file, ".");
$newfilename = $filename.$extension;
move_uploaded_file($tmpfile, $newfilename);
} else {
move_uploaded_file($tmpfile, $file);
}
?>

 

Ray

 

[chrisuk]

Well my filename is now showing correctly with both methods but neither is moving the file to my uploads directory?

 

i tried defining the upload directory, "$target_path = "uploads/";" and then using that like i did before in the move_uploaded_files argument ie: move_uploaded_file($tmpfile, $newfilename, $target_path);

 

But I get Warning: Wrong parameter count for move_uploaded_file() in /home/ca3csn/public_html/COM313/tcnet/test/uploader.php on line 11

 

File names are right though, eg

 

File469823764.doc

 

Thanks for the help so far!

 

 

[craygo]

I through this together to test. Take it apart and use what you want, but it works fine for me

 

<?php
if(isset($_POST['submit'])){
$dir = "images/";
$file = $_FILES['uploads']["name"];
$tmpfile = $_FILES['uploads']["tmp_name"];
  if(file_exists($dir.$file)){
  $filename = substr($file,0,strrpos($file, "."));
  $filename .= rand();
  $extension = strrchr($file, ".");
  $newfilename = $filename.$extension;
    if(!move_uploaded_file($tmpfile, $dir.$newfilename)
    echo "Could not upload file";
    } else {
    echo "File uploaded";
    }
  } else {
    if(!move_uploaded_file($tmpfile, $dir.$file)){
    echo "Could not upload file";
    } else {
    echo "File uploaded";
    }
  }
} else {
?>
<form action="<?=$_SERVER['PHP_SELF']?>" method="post" enctype="multipart/form-data">
<p>Pictures:<br />
1 <input type="file" name="uploads" /><br />
<input type="submit" name=submit value="Send" />
</p>
</form>
<?php
}
?>

 

Ray

[chrisuk]

Thanks very much guys - I had to modify that a little ray, just due to the odd syntax error -but it's now working great. I've also removed the conditions so that the filename is always appended with a random value, as i want to write the output to a database so one variable name is better, as opposed to seperate ones for existing and new files.

 

Most appreciated