Fatal error: Cannot pass parameter 1 by reference

Example for Fatal error: Cannot pass parameter 1 by reference

1. &
/***************Error*******************/
$a = test(array());

echo $a;
function test(&$value=array())
{
    return $value;
}
/**********************************/

/***************Correct*******************/
$value=array();
$a =test($value);
print_r ($a);
function test(&$value=array())
{ 
    return $value;
}
/**********************************/

How to keep ssh alive on centos

By default, the SSH servers are set to disconnect clients who has been inactive or idle after a certain period of time. In order to keep the ssh session alive, you may configure the ssh server.

You may change the ClientAliveInterval, TCPKeepAlive and ClientAliveCountMax options in the sshd configuration file. After you config your ssh, please do not forget to restart your ssh server.

#sudo vi /etc/ssh/sshd_config

ClientAliveInterval 100
TCPKeepAlive  yes
ClientAliveCountMax  99999

#sudo  /etc/init.d/sshd restart

htaccess to redirect to different domain name

In order to implement direction for different domain on htaccess, please use the following configuration.

RewriteEngine on

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{HTTP_HOST} ^www\.example\.com [NC]
RewriteRule ^aaaa/([0-9]+)\.html$ /index.php?action=A&sid=$1 [QSA,L]
RewriteCond %{HTTP_HOST} ^example\.com [NC]
RewriteRule ^bbbb/([0-9]+)\.html$ /index.php?action=B&sid=$1 [QSA,L]

Install PHP55 on centos 6 based remi repos

To install php55 on centos, you need download the remi repository. Please follow the following steps to complete:
1. Download repo
   sudo rpm -Uvh http://rpms.famillecollet.com/enterprise/remi-release-6.rpm

2. Confirm the remi.repo
    /etc/yum.repos.d/remi.repo

   [remi]
name=Les RPM de remi pour Enterprise Linux 6 - $basearch
#baseurl=http://rpms.famillecollet.com/enterprise/6/remi/$basearch/
mirrorlist=http://rpms.famillecollet.com/enterprise/6/remi/mirror
enabled=0
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-remi

[remi-php55]
name=Les RPM de remi de PHP 5.5 pour Enterprise Linux 6 - $basearch
#baseurl=http://rpms.famillecollet.com/enterprise/6/php55/$basearch/
mirrorlist=http://rpms.famillecollet.com/enterprise/6/php55/mirror
# WARNING: If you enable this repository, you must also enable "remi"
enabled=0
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-remi

[remi-php56]
name=Les RPM de remi de PHP 5.6 pour Enterprise Linux 6 - $basearch
#baseurl=http://rpms.famillecollet.com/enterprise/6/php56/$basearch/
mirrorlist=http://rpms.famillecollet.com/enterprise/6/php56/mirror
# WARNING: If you enable this repository, you must also enable "remi"
enabled=0
gpgcheck=1
............

3. Install PHP55
   sudo yum install --enablerepo=remi --enablerepo=remi-php55 php php-opcache php-devel php-mbstring php-mcrypt php-mysqlnd php-phpunit-PHPUnit php-pecl-xdebug

4. Confirm the version of php
    php --version

  PHP 5.5.16 (cli) (built: Sep  3 2014 20:08:58)
Copyright (c) 1997-2014 The PHP Group
Zend Engine v2.5.0, Copyright (c) 1998-2014 Zend Technologies 

Note
 Please use the following command if you have installed PHP on your server
   yum --enablerepo=remi-php55,remi update php\*

    

ISSN Number Checker

ISSN numbers consist of 8 digits. 

To check validity of an ISSN number enter the 8 digit ISSN number in the box below. 

You may also enter one issn with hyphen, e.g. 1694-0814

http://journalseeker.researchbib.com/?action=issnChecker

Error: Package: google-chrome-stable-XXXXXXX.x86_64 (google-chrome) Requires: libstdc++.so.6(GLIBCXX_3.4.15)(64bit)

When you install chrome on centos, you may require to install : libstdc++.so.6(GLIBCXX_3.4.15)(64bit).









The error may be like:
Error: Package: google-chrome-stable-35.0.1916.114-1.x86_64 (google-chrome)
           Requires: libstdc++.so.6(GLIBCXX_3.4.15)(64bit)

Now you may try to install chromium compiled for centos.


1. Download
    wget http://people.centos.org/hughesjr/chromium/6/x86_64/RPMS/chromium-31.0.1650.63-2.el6.x86_64.rpm

2.install
   rpm -ivh chromium-31.0.1650.63-2.el6.x86_64.rpm




Now you may use chrome on your centos.

MYSQL Unix time stamp conversion

When you want to convert the time stamp on mysql, please use the following code

1. time stamp to time
select FROM_UNIXTIME(1425933810);
+---------------------------+
| FROM_UNIXTIME(1425933810) |
+---------------------------+
| 2015-03-10 05:43:30       |
+---------------------------+
1 row in set (0.00 sec)

2. time to time stamp

select UNIX_TIMESTAMP('2015-11-06 10:10:10');
+---------------------------------------+
| UNIX_TIMESTAMP('2015-11-06 10:10:10') |
+---------------------------------------+
|                            1446772210 |
+---------------------------------------+
1 row in set (0.00 sec)

configure SVN server

Install
 # yum install mod_dav_svn subversion

Configure Apache
  #vi /etc/httpd/conf/httpd.conf

  LoadModule dav_module modules/mod_dav.so

Configure subversion
 # vi /etc/httpd/cond.d/subversion.conf


LoadModule dav_svn_module     /usr/lib/httpd/modules/mod_dav_svn.so
LoadModule authz_svn_module   /usr/lib/httpd/modules/mod_authz_svn.so
...

   DAV svn
   SVNParentPath /home/svn
< Location /repos>
   DAV svn
   SVNParentPath /home/svn
#
#   # Limit write permission to list of valid users.
#   < LimitExcept GET PROPFIND OPTIONS REPORT>
#      # Require SSL connection for password protection.
#      # SSLRequireSSL
#
#      AuthType Basic
#      AuthName "Authorization Realm"
#      AuthUserFile /path/to/passwdfile
#      Require valid-user
#
#       
#     Order Deny,Allow
#        Deny from all
#      Allow from 192.168.  
#
#  < /LimitExcept>
< /Location>  
 

Create repos
# mkdir /home/svn
# svnadmin create /home/svn/Test
# chown -R apache:apache /home/svn/Test

Restart the apache
 # service httpd reload

Note:
SVNPath: for single svn project
SVNParentPath: for multiple svn project
If you use  SVNParentPath, you should access sub-svn from the browser, or you will get
------------------------------------------------------------

Forbidden

You don't have permission to access /repos on this server.
--------------------------------------------------------------------------------------
You should access them by http://localhost/repos/sub-svn


p.s.
Create basic auth
htpasswd -c /path/to/passwdfile svn-admin

IP permisison   
       Order Deny,Allow
        Deny from all
        Allow from 192.168.10.126

Get the client browser language class to realize the Multi-regional and multilingual sites

/**
 * /Language.php
 * $Date::                           #$
 * @version $Rev$
 * @package Language
 */

namespace utility\i18n;

/**
 * Description of Language
 *
 * @package Language
 */
class Language
{

    /**
     * Language parameter
     */
    const LANGUAGE = 'hl';

    /**
     * Default Language
     */
    const DEFAULT_LANGUAGE = 'en';

    /**
     * Supported Language List
     *
     * @var array
     */
    private $supportedLanguage = array(
        'en' => 'English',
        'ja' => '日本語',
        'zh' => '中文',
        'ko' => '한국어',
    );

    /**
     *
     * @var string
     */
    private $languge = 'en';

    /**
     * Language Constructor
     */
    public function __construct()
    {
        $hl = isset($_GET[self::LANGUAGE]) ? $_GET[self::LANGUAGE] : @$_COOKIE[self::LANGUAGE];

        if (!$hl) {
            $hl = substr($_SERVER['HTTP_ACCEPT_LANGUAGE'], 0, 2);
        }

        $this->setLanguage($hl);
    }

    /**
     * Change the browser language
     *
     * @param string $hl
     * @return \utility\i18n\Language
     */
    public function setLanguage($hl)
    {
        if (!isset($this->supportedLanguage[$hl])) {
            $hl = self::DEFAULT_LANGUAGE;
        }
        $this->languge = $hl;

        return $this;
    }

    /**
     * Return the browser default language
     *
     * @return string
     */
    public function getLanauge()
    {
        return $this->languge;
    }

    /**
     * Return the default langauge name
     *
     * @return string
     */
    public function getLanguageName()
    {
        return $this->supportedLanguage[$this->languge];
    }

    /**
     * Return the supported language list of application
     *
     * @return array
     */
    public function getSupportedLanguage()
    {
        return $this->supportedLanguage;
    }

    /**
     * Return the language instance
     *
     * @staticvar null $instance
     * @return \self
     */
    static public function getInstance()
    {
        static $instance = null;

        if (!$instance) {
            $instance = new self;
        }
        return $instance;
    }

}

Usage


use utility\i18n\Language;


$language = Language::getInstance();
echo $language->getLanguageName();

PATH LOSS PREDICTION FOR GSM MOBILE NETWORKS FOR URBAN REGION OF ABA, SOUTH-EAST NIGERIA

PATH LOSS PREDICTION FOR GSM MOBILE NETWORKS FOR URBAN REGION OF ABA, SOUTH-EAST NIGERIA

difference between strtr and str_replace in php

strtr and str_replace may replace one string with other string or multiple strings.

But  they have little difference. You should take care of using them. Now I give some difference between them.

strtr usage

string strtr ( string $str , string $from , string $to )
string strtr ( string $str , array $replace_pairs )

str_replace usage
mixed str_replace ( mixed $search , mixed $replace , mixed $subject [, int &$count ] )

1. with two strings
$string = "1.10.0101";
echo strtr($string, '01', 'a'), '
'; // only replace 0 with a
echo str_replace('01', 'a', $string), '
'; //only replace 01 with a

output
1.1a.a1a1
1.10.aa

2. with array
$string = "1.10.0101";
echo strtr($string, array("1" => "10", "10" => "b")), '
'; //first replace 10 with b, then replace 1 with 10, but it will not replace the newly replaced value

echo str_replace(array("1", "10"), array("a", "b"), $string); // first replace 1 with a, then based on newly replaced string, replace 10 with b

output
10.b.0b10
a.a0.0a0a

3. str_replace can replace more string with one same string
$string = "1.10.0101"; 
echo strtr($string, array("1" => "x", "10" => "x")), '
';
echo str_replace(array("1", "10"), 'x', $string), '
';

output
x.x.0xx
x.x0.0x0x

Generating Random Passwords Class with PHP

 You may create one random string or strong random password by using the following php  class at will.


/**
 * Description of RandomString
 *
 * @package
 */
class RandomString
{
    /**
     *
     * @param int $length
     * @return string
     */
     static public function getRandom($length)
    {
        $randomData = base64_encode(file_get_contents('/dev/urandom', false, null, 0, $length) . uniqid(mt_rand(), true));      
        return substr(strtr($randomData, array('/' => '', '=' => '', '+' => '')), 0, $length);
    }

}