Possible render bug - reports needed.

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matt_t_hat
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Possible render bug - reports needed.

Postby matt_t_hat » Mon Jul 10, 2006 9:12 am

There appears to be a bug and it may or maynot be assosiated with skins... but probably whereby installs of Nucleus sometimes return a blank page.

It has been reported with fresh installs and I have seen it happen intermitently with lordmatt.co.uk which is not a fresh install.

It is possible that this is a shared hosting issue, a failed to connect to something issue or something else.

I'm trying to build a picture of what is going on so that I can formally submit a bug report... however a "some-sorta-error" report is going to help no one.

Anyone else with expirence of this?
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roel
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Postby roel » Mon Jul 10, 2006 12:28 pm

What I've encountered is that sometimes templates are not populated upon installation. See:
http://nucleuscms.org/forum/viewtopic.php?t=12022
http://nucleuscms.org/forum/viewtopic.php?t=10853
http://nucleuscms.org/forum/viewtopic.php?t=9612

Is that also what you mean?
Is your question not solved yet?
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roel
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Postby roel » Fri Jul 14, 2006 2:24 pm

Here's another report of a blank front page after a new Nucleus install:
http://nucleuscms.org/forum/viewtopic.php?t=12820
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Postby matt_t_hat » Sat Jul 22, 2006 11:06 pm

It appears that it is one symptom many paths and one point of weakness.

The point of weakness is the skin parser which needs to throw errors on 403 with files and no text to parse situations.

These threads also cover this issue

these are rights issues:
http://nucleuscms.org/forum/viewtopic.php?t=12733
http://nucleuscms.org/forum/viewtopic.php?t=12539
http://nucleuscms.org/forum/viewtopic.php?t=12911

Damaged files:
http://nucleuscms.org/forum/viewtopic.php?t=12820

possibly related:
http://nucleuscms.org/forum/viewtopic.php?t=12849
http://nucleuscms.org/forum/viewtopic.php?t=12383

It seems that there are two "missing" functions in the parser.

(a) The parser needs to throw a 403 into the skin if the file can not be included.
(b) The parser needs to throw a "WTF-Error" on nothing to parse.

This will dort the sheep from the goats somewhat and help to run errors to ground much faster.

Possible actions to fix the white screen of doom.

Refresh the hell out of it for a while.
Walk away and have a coffe then repeat step one.
CHMOD all skin files and folders 777 - this seems to work for no real reason and is probably releated to the 403 issue.
Get your host to flush cache/reboot server
Get host to flush entries for IP address as they relate to you skins folder.
swear under you breath and return to refreshing
Randomly tweak stuff
irritate your host into checking for "bugs"/"hackers" or whatever.
Get your host to check bug reports on all PEAR packages (???apparently...)
Keep refreshing
Get your ISP to fluch thier cache (this'll take a little more effort)
If you have a dynamic IP force a new one.

Eventually this list will fix your issue but it does not help us track down the root causes.

I have expirenced script altered files getting incorrectly CHOWNed (is that the right term?) and have to ask for an itterative CHOWN back to my username about once every six months, this might be an issue.

The trick here is going to be identify how many bugs/problems/errors/mistakes/host-issues we have bundled into one "problem".
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Postby matt_t_hat » Sun Jul 23, 2006 11:20 am

I am told that this error was logged and that is why the skin files were not loading:

[Sun Jul 23 03:36:58 2006] [crit] [client 65.254.32.50] (13)Permission denied: /home/xxxxxxxx/public_html/skins/mono/.htaccess pcfg_openfile: unable to check htaccess file, ensure it is readable
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roel
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Postby roel » Sun Jul 23, 2006 12:40 pm

matt_t_hat wrote:It appears that it is one symptom many paths and one point of weakness.

*cut*

The trick here is going to be identify how many bugs/problems/errors/mistakes/host-issues we have bundled into one "problem".


I agree. But I'm not sure where to start. I don't recall encountering an issue like this myself.
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Postby matt_t_hat » Mon Jul 24, 2006 12:49 pm

roel wrote:
matt_t_hat wrote:It appears that it is one symptom many paths and one point of weakness.

*cut*

The trick here is going to be identify how many bugs/problems/errors/mistakes/host-issues we have bundled into one "problem".


I agree. But I'm not sure where to start. I don't recall encountering an issue like this myself.
I have set up about six or seven NucleusCMS sites since I found it and have encountered it twice. LordMatt.co.uk and Jokerzxiii.co.uk both are on the same server with all but one of the others which have had no problem. Skin-show which is on the lordmatt domain has only had a hacker problem (!) not this one.

That said lordmatt has the white sreen of publishing doom from time to time and one or two others laityonline.co.uk for example show it but not as often.

There is definitly some underlieing connection but as with all intermitent issues they are they devils own backside to trace.
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I have cracked it!!!

Postby matt_t_hat » Thu Aug 03, 2006 10:20 am

I think.

In addition to some lesser known CHMOD issues which need to be FAQ'd from chitchat (sticky) and the need to ensure index has the execute right there also seems to be a constipation issue.

That's right NucleusCMS needs laxitives.

Here they are.

include this at the very end (but before the ?>) of your index.php or other blog file.

Code: Select all

<?php
   echo "<!--start flush-->";
   @ob_flush();
   @flush();
   echo "<!--end flush-->";
?>


the two comments will appear at the end and php will do it's best to remember to send the body as well as the headers.

I'll let you know if this now covers all the issues.
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Postby matt_t_hat » Thu Aug 03, 2006 10:40 am

Yes this now works on a fragment file that was not working.

It seems the issue crops up when the server is not coping so well. I reduced the strain on the server with my big htaccess by moving the forcetypes near the top.

So the issue is this:

When a server is under powered it may not send the html before it times out. Adding the flush forces the script to compleate and send unless the server is beyond help in which case the browser will time out the connection.

It is possible that the parser is effected by the time outs internal to php/server amd so never finishes wich creates the white screen of doom issue.

This needs to be addressed so that NucleusCMS is not incorrectly blamed for bad servers.

Further more the need to put the forcetypes file near the top of a htaccess file needs to be streesed in the FAQ so that users with big htaccess files are not shooting themselves in the foot so to speak
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Postby xiffy » Wed Sep 20, 2006 10:58 pm

Okay, just a quick note to the many white pages threads.
I was reading some threads and remembered that you Matt had php version 5 installed.
Maybe it's smart to remind you and all others that php version 5 has error logging done to file, not screen. In php version 4 errors were outputted to screen on a 'production' server this is considered not done. So errors go to your server error log.
Most if not all white screens of death as you call them are php error's of php not beeing able to compile a file. The error was in version 4 thrown in your face. In version 5 you have to delve into your error log of the server.

I think it's to smart to start your investigations there. It might shed some light on this issues.
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Postby matt_t_hat » Fri Sep 29, 2006 2:32 pm

xiffy wrote:Okay, just a quick note to the many white pages threads.
I was reading some threads and remembered that you Matt had php version 5 installed.
Maybe it's smart to remind you and all others that php version 5 has error logging done to file, not screen. In php version 4 errors were outputted to screen on a 'production' server this is considered not done. So errors go to your server error log.
Most if not all white screens of death as you call them are php error's of php not beeing able to compile a file. The error was in version 4 thrown in your face. In version 5 you have to delve into your error log of the server.

I think it's to smart to start your investigations there. It might shed some light on this issues.


Extreamly well remembered however my live version is a standard php4 install (php5 is for home use only).

I have only anicdotal evidence for it but it looks like an issue as much with apache and the computer than anything "wrong". By reducing the htaccess file size I've reduced white screen errors by the same ammount.

This points to the process getting killed off and an empty txt/html being returned to the requesting browser.

There is the question of can we do anything about this?
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Postby matt_t_hat » Mon Oct 30, 2006 7:35 pm

Interesting message in my box.

While doing some spam blocking and filter reviews I found this message:

A message sent to you by an anonymous visitor
(Posted from a Nucleus weblog at http://lordmatt.co.uk/)

Message:

Hello

Sorry to disturb you this way, but I've got one small thing about this bug:
http://nucleuscms.org/forum/viewtopic.php?t=12797

I've this bug on one of my blogs.
It was strange because it concerned Internet Explorer only - my primary browser Opera was unaffected.
My provider told me that it was NP_Gzip that messed things
I disabled it and the problem dissapeared.

Regards
Zibi

-----------------------------
Powered by Nucleus CMS
(http://www.nucleuscms.org/)


This seems to support the theory that it is a very low level issue.
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Postby LordMatt » Sun Nov 17, 2013 9:25 am

Since all this I have learned that white screen only is more often a case of error before content. Unfortunately the only way to force error reporting on to the screen is by editing a core file. I can fix that if you let me near the dev code for a bit.

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