I want to let users upload pics to the server but I`m having problem figuring out how to tell $_FILES what the file name should be?

Here is my upload form that I tried to use :

 here $photo_id = $user_name.time() .


 <form enctype="multipart/form-data" action="upload.php" method="POST">
 <input type="file"  name"<?php echo md5($photo_id)?>" />
 <input type="submit" value="upload"/>
 </form>

Here is the part where I get stuck how do I name the file? I can`t use this way : $_FILES[$_POST[md5($photo_id)]]['name'] as you can see I have the same proble with $_POST giving such a weird expression . I wil开发者_如何学Gol also be updating mysql database with the filename .

Can anyone suggest a better way of naming files so that filesnames don`t clash . If I use a simple file name , it may coincode with some other file of same name and overwrite ? tHANKX!

It doesn't make sense to give the file field's name an altering value.

Give it a constant value:

<input type="file"  name="photo" />

If you want to suggest a file name, use a separate hidden field:

<input type="hidden" name="filename" value="<?php echo md5($photo_id)?>">

However note that this could be manipulated by the user. You will probably be better off doing the md5() later on server side, before actually storing the file - if you want to use it at all, because

Can anyone suggest a better way of naming files so that filesnames don`t clash . If I use a simple file name , it may coincode with some other file of same name and overwrite ?

there is a number of things you can do (there are excellent answers for this on SO already listing all the options and their advantages and disadvantages, but I can't find any of them right now!). One method that is fairly safe is combining the value of the photo's name or the user's ID, and the current microtime(). The danger of collisions this way is microscopic.

1'st look again at your HTML and correct errors

<form enctype="multipart/form-data" action="upload.php" method="POST">
<input type="file"  name="photo" />
<input type="submit" value="upload"/>
</form>

2'st after submit

<?php
     $uploadedFile = $_FILES['photo']['name']; // uploaded file - for db name and md5()
     $tmpName = $_FILES['photo']['tmp_name']; // uploaded tmp file
     // I assume you are not handling users for web form and you are storing them in a session, if you need additional input on form you can add some hidden values.
     $newFile = md5($uploadedFile.time().$_SESSION['user']);
     move_uploaded_file($tmpName, $uploads_dir/$newFile);
?>

You only need to use a simple name for the file input:

<form enctype="multipart/form-data" action="upload.php" method="POST">
<input type="file"  name"myFile" />
<input type="submit" value="upload"/>
</form>

Then when your form is submitted, the uploaded file can be referenced using $_FILES['myFile'].

The file will be uploaded to temporary storage, and you then have to use a function such as move_uploaded_file() to move it to permanent storage.

Something like:

$tmp_name = $_FILES['myFile']['tmp_name'];
$name = $_FILES['myFile']['name'];
move_uploaded_file($tmp_name, 'uploads/' . $name); // Move file to /uploads folder

http://uk.php.net/manual/en/function.move-uploaded-file.php has some more info

Update

If you want to make sure that you're not overwriting files with the same name, use file_exists().

if(file_exists($_FILES['myFile']['name']))
{
    // File already exists
}