How to detect that a file is being uploaded over FTP

by

There’s no generic solution to this problem.

Some FTP servers lock the file being uploaded, preventing you from accessing it, while the file is still being uploaded. For example IIS FTP server does that. Most other FTP servers do not. See my answer at Prevent file from being accessed as it’s being uploaded.

There are some common workarounds to the problem (originally posted in SFTP file lock mechanism, but relevant for the FTP too):

  • You can have the client upload a “done” file once the upload finishes. Make your automated system wait for the “done” file to appear.

  • You can have a dedicated “upload” folder and have the client (atomically) move the uploaded file to a “done” folder. Make your automated system look to the “done” folder only.

  • Have a file naming convention for files being uploaded (“.filepart”) and have the client (atomically) rename the file after upload to its final name. Make your automated system ignore the “.filepart” files.

    See (my) article Locking files while uploading / Upload to temporary file name for an example of implementing this approach.

    Also, some FTP servers have this functionality built-in. For example ProFTPD with its HiddenStores directive.

  • A gross hack is to periodically check for file attributes (size and time) and consider the upload finished, if the attributes have not changed for some time interval.

  • You can also make use of the fact that some file formats have clear end-of-the-file marker (like XML or ZIP). So you know, that the file is incomplete.

Some FTP servers allow you to configure a hook to be called, when an upload is finished. You can make use of that. For example ProFTPD has a mod_exec module (see the ExecOnCommand directive).

More Related Contents:

  1. Full Secure Image Upload Script
  2. How to upload file ( picture ) with selenium, python
  3. Multiple files upload in Codeigniter
  4. This application has no explicit mapping for /error
  5. Upload File to FTP Server on iPhone
  6. Uploading Files in ASP.net without using the FileUpload server control
  7. Google Forms file upload complete example
  8. Upload file to FTP using C#
  9. PHP – Upload utf-8 filename
  10. POST data using the Content-Type multipart/form-data
  11. How to upload file in Angular2
  12. PHP ftp_put fails
  13. Python Script Uploading files via FTP
  14. Preview Image before uploading Angularjs
  15. How to limit the number of dropzone.js files uploaded?
  16. How to avoid OutOfMemoryError when uploading a large file using Jersey client
  17. How to check if an uploaded file is an image without mime type?
  18. Upload file and download file from FTP
  19. Html helper for
  20. Ajax file upload
  21. multiple files upload using same input name in django
  22. ini_set(“upload_max_filesize”,”200M”) not working in php [duplicate]
  23. FtpWebRequest returns error 550 File unavailable
  24. File uploading using GET Method
  25. Multiple file upload with Symfony2
  26. Upload file bigger than 40MB to Google App Engine?
  27. Secure User Image Upload Capabilities in PHP
  28. the dreaded “Warning: imagecreatefromjpeg() : ‘/tmp/filename’ is not a valid JPEG file in /phpfile.php on line xxx”
  29. What’s the best way to create a single-file upload form using PHP?
  30. Remove selected file(s) before upload with Javascript

Leave a Comment