在多个文件上传中管理php会话

Question

I'm working in a multiple image upload social web app. I'm assigning a $_session['file_id'] to each uploaded file as an array index (file id comes from db). But I only want users to upload a maximum of 4 images per post. So I'm counting the images.length before upload, and if it's == 4 , alerting the user he can't upload more files at the same time, else, the normal upload happens. For security purposes I have an unset($_session['file_id']) for making sure the 4 files won't be uploaded on errors, or user changes on javascript (a for loop on every upload, to count $_session['file_id']) . The problem I'm having is that the js itself ain't enought to make sure the file ain't uploaded 4 times, I guess ajax upload stay on queue, and check for file number before the 4th file is uploaded. Is there any other approach I can use direct on php, remembering I can't unset files for common users (4 files are already upload and waiting for send button), but I need plus to unset files if user reflesh, or quit the page? Thank your for your time.

JavaScript

var checkfilecount = 0;
$('#file').change(function() {
    checkfilecount++;
    checkfile = $("#images).length;
    if (checkfile < 4 && checkfilecount < 4) {
        $("#filesend").submit();
    }
    else {
        setTimeout(function(){
            alert("Sorry, You can`t upload too many files at once")
        },3000)
    }
})  

and on #postsend:

checkfilecount = 0;

PHP

if (isset($_SESSION['files_id'])) {
    $counting = 0; 
    foreach($_SESSION['files_id'] as $key => $val)
    {
        $counting++;
        if ($counting == 4) {
            unset($_SESSION['files_id']);       
            exit("error on session array"); 
        }   
    }   
}

Answer 1

Assign a random classname to the <input> s for example:

<form action="" method="post" enctype="multipart/form-data">
    <input type="file" name="file[]" class="fileuploadCounter">
    <input type="file" name="file[]" class="fileuploadCounter">
    <input type="file" name="file[]" class="fileuploadCounter">
    <input type="file" name="file[]" class="fileuploadCounter">
</form>

After init, $('.fileuploadCounter').length() will return the amount of elements with that class, in this example, four. See the jQuery documentation .

---

Old answer underneath

Change the name on the <input> tags to images[] , and count $_POST['images'] server side.

Eg:

 <form action="" method="post" enctype="multipart/form-data"> <input type="file" name="file[]"> <input type="file" name="file[]"> <input type="file" name="file[]"> <input type="file" name="file[]"> </form> <?php if($_SERVER['REQUEST_METHOD'] == "POST"){ if(isset($_FILES['file'])){ // Because we added [] in the name tag and they match names, $_FILES['file'] is now an array containing the images. if(count($_FILES['file']) > 4){ // More than 4 files } else { // Less then four! foreach($_FILES['file'] as $file){ move_uploaded_file($file["file"]["tmp_name"], "uploads/" . $files["file"]["name"]); } } } } ?>