File upload problems via HTTP

When attempting to transfer large files over 1-2MB in size via HTTP, you will probably run into timeout problems. All scripting languages have a timeout set in our system. For example, PHP is set to 90 seconds and Perl is set to 300 seconds. When you post form data to a script (form data can contain files to upload), all of the data must be sent and received by the server before the script can start executing. Unfortunately, this time is counted as script execution time and is subject to the global timeout.

Normally, form data is very small in size and usually only contains contact information or a short message and can be uploaded in a matter of seconds, but if the form data contains files, the upload time increases. The amount of time it takes to upload this form data is based on the speed of the client -> server connection. On a broadband connection, you can safely say a 1-2MB file upload will upload without any problems. On a dialup connection, you will begin to encounter problems as your file size approaches 1MB.

While it is possible to change this timeout setting in PHP, HTTP is generally very unstable for large file transfer because of its connectionless nature. You cannot be guaranteed that your transfer will complete. We do not recommend and will not support the transfer of large files via HTTP unless you are using a file upload component such as AspUpload which operates in a manner that bypasses server timeout problems. ASPUpload will not fail on large file transfers. Another option is to utilize FTP which is a connection based protocol and can recover from errors encountered during the upload process.

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