Sessions
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Session Upload Progress

When the session.upload_progress.enabled INI option is enabled, PHP will be able to track the upload progress of individual files being uploaded. This information isn't particularly useful for the actual upload request itself, but during the file upload an application can send an POST request to a separate endpoint (via XHR for example) to check the status.

The upload progress will be available in the $_SESSION superglobal when an upload is in progress, and when POSTing a variable of the same name as the session.upload_progress.name INI setting is set to. When PHP detects such POST requests, it will populate an array in the $_SESSION, where the index is a concatenated value of the session.upload_progress.prefix and session.upload_progress.name INI options. The key is typically retrieved by reading these INI settings, i.e.

<?php
$key 
ini_get("session.upload_progress.prefix") . ini_get("session.upload-progress.name");
var_dump($_SESSION[$key]);
?>

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 a upload is cancelled like this, the error key in $_FILES array will be set to UPLOAD_ERR_EXTENSION.

The session.upload_progress.freq and session.upload_progress.min_freq INI options control how frequent the upload progress information should be recalculated. With a reasonable amount for these two settings, the overhead of this feature is almost non-existing

Example #1 Example information

Example of the structure of progress upload array.

<form action="upload.php" method="POST" enctype="multipart/form-data">
 <input type="hidden" name="<?php echo ini_get("session.upload_progress.name"); ?>" value="123" />
 <input type="file" name="file1" />
 <input type="file" name="file2" />
 <input type="submit" />
</form>

The data stored in the session will look like this:

<?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(
  
=> 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// Amount of bytes received and processed for this file
  
),
  
// An other file, not finished uploading, in the same request
  
=> array(
   
"field_name" => "file2",
   
"name" => "bar.avi",
   
"tmp_name" => NULL,
   
"error" => 0,
   
"done" => false,
   
"start_time" => 1234567899,
   
"bytes_processed" => 54554,
  ),
 )
);


Sessions
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PHP手册 - N: Session Upload Progress

用户评论:

wojbach at o2 dot pl (05-Mar-2012 08:41)

"session.upload-progress.name" -> whether here shouldn't be a underscore instead of a dash

powtac at gmx dot de (02-Mar-2012 04:35)

takeone (02-Dec-2011 03:12)

IE6 does not inherit session when you launch new browser from start menu or shortcut.It's the feature.
It is recommended that upload form and progress bar are on same window.

gerd dot randolf at web dot de (09-Nov-2011 03:29)

Note that this will be available from PHP 5.4 on. It won't work in PHP 5.3 or earlier.