I've noticed in /var/log/apache2/error.log on one of the Debian servers I manage a lot of warnings and errors produced by tidy – HTML syntax checker and reformatter program.
There were actually quite plenty frequently appearing messages in the the log like:
...
To learn more about HTML Tidy see http://tidy.sourceforge.net
Please fill bug reports and queries using the "tracker" on the Tidy web site.
Additionally, questions can be sent to html-tidy@w3.org
HTML and CSS specifications are available from http://www.w3.org/
Lobby your company to join W3C, see http://www.w3.org/Consortium
line 1 column 1 - Warning: missing <!DOCTYPE> declaration
line 1 column 1 - Warning: plain text isn't allowed in <head> elements
line 1 column 1 - Info: <head> previously mentioned
line 1 column 1 - Warning: inserting implicit <body>
line 1 column 1 - Warning: inserting missing 'title' element
Info: Document content looks like HTML 3.2
4 warnings, 0 errors were found!
...
I did a quick investigation on where from this messages are logged in error.log, and discovered few .php scripts in one of the websites containing the tidy string.
I used Linux find + grep cmds find in all php files the "tidy "string, like so:
server:~# find . -iname '*.php'-exec grep -rli 'tidy' '{}' ;
find . -iname '*.php' -exec grep -rli 'tidy' '{}' ; ./new_design/modules/index.mod.php
./modules/index.mod.php
./modules/index_1.mod.php
./modules/index1.mod.php
Opening the files, with vim to check about how tidy is invoked, revealed tidy calls like:
exec('/usr/bin/tidy -e -ashtml -utf8 '.$tmp_name,$rett);
As you see the PHP programmers who wrote this website, made a bigtidy mess. Instead of using php5's tidy module, they hard coded tidy external command to be invoked via php's exec(); external tidy command invocation.
This is extremely bad practice, since it spawns the command via a pseudo limited apache shell.
I've notified about the issue, but I don't know when, the external tidy calls will be rewritten.
Until the external tidy invocations are rewritten to use the php tidy module, I decided to at least remove the tidy warnings and errors output.
To remove the warning and error messages I've changed:
exec('/usr/bin/tidy -e -ashtml -utf8 '.$tmp_name,$rett);
exec('/usr/bin/tidy --show-warnings no --show-errors no -q -e -ashtml -utf8 '.$tmp_name,$rett);
The extra switches meaning is like so:
q – instructs tidy to produce quiet output
-e – show only errors and warnings
–show warnings no && –show errors no, completely disable warnings and error output
Onwards tidy no longer logs junk messages in error.log Not logging all this useless warnings and errors has positive effect on overall server performance especially, when the scripts, running /usr/bin/tidy are called as frequently as 1000 times per sec. or more
