Shouts being duplicated

[allyours]

This has been going on for maybe two  months now but shouts are being duplicated from time to time on their own. Sometimes as many as three or four times. Someone will make a shout then maybe a few minutes you could refresh the page and there would be a duplicate of the shout. I've even tried to remove a dupe only to find it duplicating again later on. Anyone else having a problem like this? I think our shoutbox number is 78.

[FiXato]

is it possible that those who make those duplicate posts, keep the page open after the post, and when they refresh to see new posts, they resubmit their posts?

[Adonis]

I don't think they are duplicated on their own. I just checked the database, and found that there are minutes between the first and second post. Sometimes there is an hour between the first post and last duplicate. Apache logs show that they are all sent by the browser with POST headers. This means that the browser sent the post request and the script simply acts on that. I also checked a few other boxes, and it seems (from as far as i could see it) this behaviour only happens with your box and only with a few of your users.

What fixato suggested might be what's happening. Maybe they have opened the shoutbox without opening your site, post a shout, and then refresh after some time. That causes (in IE at least) the browser to resend post headers. Usually IE shows a popup warning you about this.

I could build in a check that checks for reposts, but sometimes reposts are intended by the user.

[allyours]

Is this the popup message your talking about?

That occurred for me when I post, then refresh the browser. I seriously doubt they have opened the shoutbox without opening our site.
Some duplicate postings have happened to me and they weren't intentional. Refreshing browser or box might be in part the cause. As I went through my bin of deleted shouts it looks like it may have started sometime just before November (around Halloween).

[FiXato]

That is indeed the popup we were talking about.
When you click on retry then, it will post the same shout data again as you used for posting your message; in other words: it will post your message again.

[Adonis]

This even occurs when you refresh the the parent page, which holds the shoutbox iframe? I mean, i do get that message when i refresh the shoutbox page after posting a shout, but i do not get that message when i refresh the parent page hosting the shoutbox.

[allyours]

LOL OK, I'm not saying that by refreshing the page that it was the reason for duplicate posting but I made that screen shot by refreshing the page after posting a shout just to put it to the test. I did click Retry and when I looked at the shoutbox, there was no duplicate. If this indeed was the reason then it's not consistent.

EDIT:
OK, just put it to the test again. The other time I had tried to refresh before 60 seconds (within the flood control limit). This time I waited over a minute and YES, it did duplicate the shout. It still is very strange though because we've never had this problem before the time I mentioned in my previous post here.

I think I'm going to try and put this to the test on our beta2.

Update:
The beta2 didn't show the popup nor did it warn me about the repost limit which is set to 25 secs. The repost limit might have a bug in beta2. Oh, and it didn't duplicate my post either. There is no bug in the repost. It does work when trying to repost rather than page refresh.

Update2:
Ummm, OK. Strange things going on here. Maybe you know what's up. Went back to our home page where I mentioned that I did get the duplicate shout and I had deleted both copies (original and duplicate). Just thought I'd refresh that page and what do I see?
IP Mismatch. Shout not deleted.
What's up with that? 

[Adonis]

Update2:
Ummm, OK. Strange things going on here. Maybe you know what's up. Went back to our home page where I mentioned that I did get the duplicate shout and I had deleted both copies (original and duplicate). Just thought I'd refresh that page and what do I see?
IP Mismatch. Shout not deleted.
What's up with that? 

Well if you refresh, then your browser resends the headers. In a repost, it sends POST headers. In case you delete your shout, it sends GET headers. In this case you send the delete request again, your shout was already deleted, and since you can't delete an already deleted shout, it gives this error message. The message itself is primarily used for trying to delete a shout that's not yours.

[allyours]

Well if you refresh, then your browser resends the headers. In a repost, it sends POST headers. In case you delete your shout, it sends GET headers. In this case you send the delete request again, your shout was already deleted, and since you can't delete an already deleted shout, it gives this error message. The message itself is primarily used for trying to delete a shout that's not yours.

That makes sense to me. 
What doesn't seem to make sense though is why none of these repost and duplicate problems ever happened before late October? I'm sure that in the 2 years or so we have been using this shoutbox that there had to have been refreshing of page after posting.

I must be off to work now. I'll be checking back for any other updates on this. Thanks for the replies thus far. This is still a "rockin" shoutbox.

[Adonis]

I think i have an idea on why this happens now. Some time ago i had to implement the caching features that were meant for the new version, into the current version. This was needed because the server couldnt handle the 15 million or so shoutbox loads per month anymore. This caching feature handles things differently. It's not implemented on Xignashout though, since there isnt much load there.

I'll try think about a way to solve this resending of headers, because i understand it's causing troubles for you. I can't promise it will be a quick solution though.