问题
I recently implemented Fine Uploader and it's been mostly successful. A few users are however are not able to upload. They are all using modern browsers (IE10, FF and Chrome). One let me remotely access their machine and I was able to try it on both Chrome and FF.
I got the same error on both:
[10:45:28.330] "[FineUploader 3.8.0] Received response status 403 with body: <?xml version="1.0" encoding="UTF-8"?>
<Error><Code>AccessDenied</Code><Message>Invalid according to Policy: Policy expired.</Message><RequestId>--removed--</RequestId><HostId>--removed--</HostId></Error>"
Is it something with the timezone settings on their computer where it's generating an invalid policy?
回答1:
The timezone settings will have no effect as times are UTC. However, if the time on the user's computer is not accurate (say, off by 5 or more minutes), then the policy will be expired, according to Amazon.
Fine Uploader sets an expiration date to 5 minutes (again, in UTC). The date used is generated in the browser, so your client machine's time will be used. If the client machine's clock is slow by 5 or more minutes, the policy will be seen as expired when Amazon handles it.
I'm fairly sure that the issue is due to a significant drift on your customer's machine clock. If you verify this, I suggest you instruct them to keep system clock synced with a time server.
Update: A new feature was added to Fine Uploader 5.5 that allows you to overcome extreme clock drift on user machines/browsers. See the clock drift section on the S3 feature page for more information.
来源：https://stackoverflow.com/questions/18520108/fine-uploader-getting-policy-expired-message-sending-to-s3-for-some