08.03.08

Trailing Whitespace Causes a Session to be Destroyed in CakePHP

Posted in PHP at 1:36 am by Guy

While working on a new project using CakePHP, I’ve came across a weird problem. In one of the controllers the the session always came out as invalid, as

$this->Session->valid()

always returned false. I tried debugging this weird stuff, and it looked like all the session variables are unset. Using

$this->Session->error()

to get the last error returned “Config doesn’t exist”. After further debugging “Config” turned out to be an internal array that is saved by CakePHP to the session and holds various internal data (some of it is used for validation like user-agent hash). I kept printing more and more debugging data as well as looking at CakePHP’s trac system.

I found an interesting bug (ticket #4217) and it looked very promising, as it almost fully described my problem. Unfortunately, the solution offered didn’t seem to work for me. But it inspired me to try and start the session manually using session_start() instead of using Cake’s startup and activate methods of the Session Component.

I found out that the session_id() returned empty string. Luckily calling session_start() directly from the controller, gave me a lead. The session seemed to work well but a nasty error about headers already been sent showed up.

I little more investigation lead up that I had a trailing newline after my closing PHP tag in that controller file. Deleting this trailing whitespace completely solved the problem. No need anymore to manually start the session. It’s pretty annoying that such a small thing like trailing new line can cause such seemingly unrelated problems in CakePHP’s session handling.

Maybe CakePHP should add a little debug notice when the session doesn’t start because header were already sent. This can be done by modifying the else statement in the __startSession() method in cake/lib/session.php (line 557 in version 1.2.0.6311). I wonder what the reason they had not to inform the developer when such event happens, as I don’t see why someone will deliberately try to start the session after sending the headers, I think it only happens by mistake (at least most of the time).

22.12.07

Vim Macros for Wrapping Strings for Gettext

Posted in PHP, vim at 1:52 pm by Guy

I’m working on a website and we decided to localize it using GNU gettext. Soon enough I found it tiring to wrap each string manually in _( and ) and also to do it in Smarty (using {t}string{/t}. So I decided that I need a macro that will let highlight the string that needs translation and the macro will wrap for me.

I ended up writing two macros one for PHP files (but it’s also good for C/C++ etc.) and one for smarty.

:vmap tg di_(<ESC>pa)<ESC>
:vmap ts di{t}<ESC>pa{/t}<ESC>

To use these macros just highlight the string for translation in vim’s visual mode and press tg (or ts), and your string will be wrapped for translation.

04.12.07

Multibyte String Truncate Modifier for Smarty - mb_truncate

Posted in PHP at 3:53 pm by Guy

When working with Smarty, a PHP templating engine, I discovered that while the regular truncate modifier works great on ASCII strings, it doesn’t work with multibyte strings, i.e. UTF-8 encoded strings. This leads to problems in internationalization (i18n), as UTF-8 is the popular encoding for non-Latin alphabets nowdays. The problem can be solved by modifying the built-in truncate modifier and create a new one that takes an additional argument, the charset of the string, and acts accordingly. The new modified modifier, mb_truncate is implemented below.
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