Aborting upload request - php

Question

I'm having an issue where I am trying to support cancelling file uploads. I would like to know what the best practice for determine whether an upload is cancellable. So how can you determine when the file has completed uploading, versus the server generating/returning a response? I understand this is possible by tracking the file progress in HTML5, but since I have to support IE9, I am running out of ideas.
The end result is if you attempt to cancel a file upload that is nearing being completely upload, and issue the abort request, you end up aborting the response and the file is happily sitting on the server.
I am using jquery to submit the request, and am cancelling via the abort() method. I see in the browser console that the request was successfully aborted.
Am I missing something trivial?

Answer 1

PHP now has the ability to track the upload progress. See "Session Upload Progress".
Use this feature to write a short script: checkUpload.php, and use AJAX to return the status back to your IE9 page.
<?php
$_SESSION["upload_progress_123"] = array(
"start_time" => 1234567890, // The request time
"content_length" => 57343257, // POST content length
"bytes_processed" => 453489, // Amount of bytes received and processed
"done" => false, // true when the POST handler has finished, successfully or not
"files" => array(
0 => array(
"field_name" => "file1", // Name of the <input/> field
// The following 3 elements equals those in $_FILES
"name" => "foo.avi",
"tmp_name" => "/tmp/phpxxxxxx",
"error" => 0,
"done" => true, // True when the POST handler has finished handling this file
"start_time" => 1234567890, // When this file has started to be processed
"bytes_processed" => 57343250, // Number of bytes received and processed for this file
),
// An other file, not finished uploading, in the same request
1 => array(
"field_name" => "file2",
"name" => "bar.avi",
"tmp_name" => NULL,
"error" => 0,
"done" => false,
"start_time" => 1234567899,
"bytes_processed" => 54554,
),
)
);
Using PHP, it is also now possible to cancel the upload process. From that same manual page referenced above, comes the following text:
It is also possible to cancel the currently in-progress file upload, by setting the
$_SESSION[$key]["cancel_upload"] key to TRUE. When uploading multiple files in the same
request, this will only cancel the currently in-progress file upload, and pending file
uploads, but will not remove successfully completed uploads. When an upload is cancelled like
this, the error key in $_FILES array will be set to UPLOAD_ERR_EXTENSION.
The only thing not covered in the PHP documentation is how to get the total file size. There is a very good review of this process here: "PHP Master | Tracking Upload Progress"