FileReference upload & Anti-Virus Software

October 21st, 2008 • ActionScript, Flash

Lately I experienced some problems with FileReference upload while using Kapersky Anti-Virus Software. The software has a feature to scan HTTP traffic for viruses which btw. is enabled by default. It uses some kind of cache which forces FileReference Events to be inaccurately or not beeing dispatched at all. As there are even more Anti-Virus Tools and Firewalls out there having similar features you should be aware of this problems.

You will notice the first problem when you try to show the upload progress. The ProgressEvent.PROGRESS bytesLoaded property will provide the bytes in the cache instead of the actual uploaded bytes. As a result your progress display will shoot up to 100% immediately on a fast Computer.

Be also careful with the usage of DataEvent.UPLOAD_COMPLETE_DATA as it doesn’t get dispatched once in a while while using the HTTP traffic scanning. Basically I guess the returning data is absorbed by the proxy, which handles the Anti-Virus cache.

The last issue is very weird but apparently Event.COMPLETE is fired before the file is completly uploaded to the server, therefore the file is not available just after the COMPLETE event, in case you want to call a convert script or something similar right after the upload. My assumption is that the proxy generates an HTTP status code of 200 which triggers the flash event when the cache is filled.

Tags: AS3, FileReference, Flash

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