Can't upload post attachments

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Kyudos
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Re: Can't upload post attachments

Post by Kyudos » Thu Sep 05, 2019 4:21 am

I'm trying to understand from the code - where does plupload try to upload to? I see in the form data a name like "o_1djvqdn4e1ikb1b2k13udbo51mrsb.png", but I don't see anything like that on the server. I'm wondering if I have a destination directory missing or something?

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EA117
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Re: Can't upload post attachments

Post by EA117 » Thu Sep 05, 2019 3:41 pm

plupload itself is using /files/plupload/ as a staging area to receive the potentially-chunked file content prior to reassembly. (Using file names based on the plupload_salt from the phpbb_config table, and an MD5 hash of the filename.) The single-chunk or reassembled file then gets copied to /files/ using it's phpBB-assigned attachment file name (the GUID-based name you mentioned earlier, and like any attachment would even absent plupload).

Your web server can certainly be staging the POST content elsewhere first, prior to handing off anything to plupload. A Process Monitor trace of a successful upload (less than 5KB) and then filtering for all the WriteFile and SetRenameInformationFile operations should show you any temp files written and/or moved or renamed during the process, in addition to showing all the activity log writing, etc.

Kyudos
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Re: Can't upload post attachments

Post by Kyudos » Tue Sep 10, 2019 3:33 am

After much dicking around, we managed to trace this to a reverse proxy rule on the fire wall. I don't really understand why that was blocking things, but it is working - at last!

Thanks very much for your time and patience!

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EA117
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Re: Can't upload post attachments

Post by EA117 » Tue Sep 10, 2019 3:58 am

Nice... glad you figured it out. If it happens to be a well-known firewall and/or a default-defined rule that others would have, and/or if there was anything in the firewall logging (once you knew to look there) that could be a clue for other phpBB or plupload users in the future, maybe dropping that information here could end up helping someone else. If not, that's all good too.

Kyudos
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Re: Can't upload post attachments

Post by Kyudos » Tue Sep 10, 2019 9:39 pm

We have several Windows virtual servers, with various forms of external traffic being routed from external IPs to their internal network addresses.

The 'problem' rule on the took all HTTP and HTTPs traffic from the (Kerio) firewall and passed it to the reverse proxy table to sort out which server it should be sent to. The fix was to specifically take all the HTTP and HTTPs traffic destined for the Web server's external IP and pass it specifically and directly to the internal IP of the server, and give this rule preference to the original. In theory, the new rule doesn't do anything materially different to the first one, but obviously does do something different.

With the 'bypass' working, at this point I'm somewhat disinclined to investigate further! :D

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EA117
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Re: Can't upload post attachments

Post by EA117 » Tue Sep 10, 2019 10:00 pm

Kyudos wrote:
Tue Sep 10, 2019 9:39 pm
With the 'bypass' working, at this point I'm somewhat disinclined to investigate further! :D
No kidding. Enough time spent already, and these beers aren't going to drink themselves. 😜

Thanks for the explanation. Not sure if the ultimate "no response at all" situation was purely on the proxy's end (squelching some response the phpBB server had actually made), versus whether it was on phpBB's end with the unexpected and/or truncated data that was being delivered to phpBB. But at least we have something to think about next time someone makes a similar observation on the plupload processing.

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