4. December 2014

Problem: Any link on Drupal site shows the same page after upgrade to Apache 2.4 and PHP 5.6

Upgrading old Linux server is challenging task. Many things could break or stop working.

One of problems was that Drupal sites with htaccess file stopped working and any URL was pointing to the same main page.

htaccess file is often use to allow creation of nice URL. It typical content was:

RewriteRule .* %{DOCUMENT_ROOT}/index.php/$0 [L]

This rule is not working with new Apache and PHP. It was necessary to replace it by:

RewriteRule ^(.*)$ index.php?q=$1 [L,QSA]

Reload Apache and Drupal site should work again.

29. June 2013

True/False gotcha Python vs Ruby vs PowerShell vs NodeJS vs PHP

Evaluation of conditions is very important part programming. True is ture, false is false…

Or not? It might surprise you, but not all languages evaluate numbers, empty strings or empty arrays in the same way.

Let’s examine several technologies. Python, Ruby, PowerShell, NodeJS and PHP.

Here is small code written in Python:

def test(value):
    if value:
        print "True"
    else:
        print "False"

test(0)
test(1)
test("")
test([])
test({})

Here is similar code written in Ruby:

def test(value)
    if value
        print "True"
    else
        print "False"
    end
end

test(0)
test(1)
test("")
test([])
test({})

Let’s compare it to PowerShell:

Function Test($value) {
    if ($value) {
        Write-Host "True"
    } else {
        Write-Host "False"
    }
}

Test(0)
Test(1)
Test("")
Test(@())
Test(@{})

Same logic in JavaScript for NodeJS:

function test(value) {
    if (value) {
        console.log("True");
    } else {
        console.log("False");
    }
}

test(0);
test(1);
test("");
test([]);
test({});

Code in PHP:

<?php 
function test($value) {
    if ($value) {
        echo "True";
    } else {
        echo "False";
    }
}

test(0);
test(1);
test("");
test(array());
test(array());
?>

Results are little bit surprising:

 

Python Ruby PowerShell NodeJS PHP
0 False True False  False False
1 True True True True True
“” False True False False False
[] False True True  True False
{} False True True  True False

You can test code on-line in Cloud9 IDE except PowerShell example 😉

8. May 2013

Vim mode in Cloud9 IDE

Cloud9 IDE is cloud base IDE for NodeJS, Python, Ruby or PHP projects.

The cool thing about this IDE is that code editor has support for Vim mode (it also supports Emacs) 🙂

vim-cloud9

Go to View, Keyboard Mode and select Vim.

Voila you can use many Vim features, like indentation by >> or many others.

Here is offical video from Cloud9 Youtube channel:

17. June 2012

How to solve some problems with Drupal after upgrade to PHP 5.4

I’ve found several interesting issue after upgrading PHP 5.3 to PHP 5.4 on Drupal 6 and Drupal 7 sites.

The first biggest problem was that Drupal was displaying Access denied message on all web pages. It was not possible to login to system. Even http://localhost/?q=admin didn’t work.

I had to create temporary session. It is quite easy when using Drush:

drush user-login

Drush displayed one time session for admin. This solved the problem with admin login.

The other issue was that there was Access denied message on every page. There were also other very useful messages flooding each page:

Notice: Undefined index: access in function _menu_link_translate() …

I spent some time searching for any hint how to resolve this weird behavior. It was necessary to delete all Drupal’s caches.

Configuration -> Development -> Performance -> Delete cache

After this clean up Drupal was working correctly.

Then I checked one older Drupal 6 site and there was nice big red warning:

Warning: strtotime() [function.strtotime]: It is not safe to rely on the system’s timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier.

The problem was that there was no default timezone in php.ini. It was sufficient to add timezone to /etc/php5/apache2/php.ini to section

[Date]
; Defines the default timezone used by the date functions
; http://php.net/date.timezone
date.timezone = "Europe/Prague"

You can find more info about timezones at php.net/date.timezone.

After reloading Apache configuration everything was ok.

19. February 2012

Tomcat 7 and curl – SSL23_GET_SERVER_HELLO:tlsv1 alert internal error

There is very annoying bug in Open SSL 1.0 which affects curl. When you try to access Tomcat 7 with https with curl you’ll get fancy error:

curl: (35) error:14077438:SSL routines:SSL23_GET_SERVER_HELLO:tlsv1 alert internal error

-k parameter is not working at all

You’re not able to invoke any request against Tomcat 7 with https in default configuration.

The solution is to restrict available ciphers in Tomcat’s https connector:

ciphers="SSL_RSA_WITH_RC4_128_SHA"

Restart Tomcat and curl will work.