My Daily Coding updates

Displaying css dropdown menu over flash object in IE8

2012-10-09T16:24:00.000+05:30

To display a css dropdown menu over an embedded flash video in IE8, do the following:

add :
1. <param name="wmode" value="opaque"/> in <object> tag and
2. wmode="opaque" in <embed> tag.

This should take care of it.

Accordion menu - making a top level menu item work as a link

2012-06-28T10:37:00.001+05:30

I was working on five-six level JQuery accordion menu to build a side navigation menu. However, i wanted to make labels with a single level menu to behave as normal links rather than the default behaviour of opening up a sub-menu on clicking the top level label.

For this, you need to capture the click event of the top level label to make it work as a normal link. Following is the solution:

The HTML code looks like:

<div id="accordion">
    <h3 class="home">
        <a href="/home" class="heading" >Home</a>
    </h3>
    <h3>
        <a href="#custom" class="heading">Custom</a>
    </h3>
    <ul>
        <li><a href="/home/mydata1">My Bio1</a></li>
        <li><a href="/home/mydata2">My Bio2</a></li>
    </ul>

    <h3>
        <a href="/home/Account" class="heading">Account</a>
    </h3>
    <ul>
        <li><a href="/home/avatar">Avatar</a></li>
        <li><a href="/home/Account">Account</a></li>
    </ul>
    <h3>
        <a href="#custom2" class="heading">Custom2</a>
    </h3>
    <h3>
        <a href="#custom3" class="heading">Custom3</a>
    </h3>
    <h3>
        <a href="#custom4" class="heading">Custom4</a>
    </h3>
    <h3>
        <a href="#custom5" class="heading">Custom5</a>
    </h3>
</div>

The js code to set up Accordion with JQuery looks like:

$(document).ready(function(){

        $('#accordion').accordion({
                header: "h3.home",
                navigation: true,
                autoHeight: false,
                clearStyle: true,
                collapsible: true,
                alwaysOpen: true,
                animated: 'slide'
        });

        $('#accordion h3.home a').click(function(){
            $('#accordion a.heading').accordion("activate", -1);                                   window.location = $(this).attr('href');
            return false;
        });
});

The line: $('#accordion a.heading').accordion("activate", -1); closes every label/header that is open.

The line: window.location = $(this).attr('href'); sets the url to navigate to, to the href value.

2012-04-26T13:45:00.000+05:30

Sessions and Cookies:

Cookies Vs Sessions: The main difference between cookies and sessions is that cookies are stored on the client side while sessions are stored on the server side.

Cookies: A cookie is a file that is stored on the client computer when visiting a website. They are typically used to store user preferences e.g. Cookies store the order, in which users want their news to be printed etc. More often than not, they are used to store any non-sensitive data on client computer. When you create a cookie, you need to specify how long you want it to be valid, and once done, it will reside on the client computer till that date until it ‘expires.’ Once a cookie has been created, the visitor’s browser will automatically send it to the web server each time the visitor visits our site. PHP then reads this value into the superglobal array: $_COOKIE, which a developer can then use to read the concerned cookie’s value as $value = $_COOKIE[‘name’];

Usage:

Following is the syntax to create a cookie:

setcookie(name,value,expire,path,domain,secure,httponly);

where:

name => name of the cookie to be stored on the client’s computer.

value => value the cookie will hold.

expire => the expiry period of the cookie

path => the path on the server in which the cookie will be available on. Default value is the current directory that the cookie is being set in.

domain => the domain on which the cookie will be available.

secure => indicates that the cookie will be transmitted only over a secure http connection i.e. only over an https:// request.

httponly => This parameter was added in PHP 5.2 and above. When set to TRUE, the cookie will be accessible only via an http protocol. It cannot be accessed by Javascript anymore.

e.g. Let us set a cookie that will expire 2 days from now. It’s typical syntax will be:

$cookieValue = “test data”;

setcookie(‘testcookie’, $cookieValue,time()+172800,’/foo’,’example.com’,1);

The above declaration will create a cookie named “testcookie” with the given value and will expire after 2 days. 2 days = 24*60*60*2 = 172800 seconds. In addition, it will available within the directory /foo and all sub-directories such as /foo/test of the domain : example.com.

Please note: The secure parameter being set to 1, indicates that the cookie will be available only on a secured HTTP connection i.e. over an https:// request only.

Sessions: A session is nothing but a combination of a client-side cookie and server-side cookie. The client-side cookie contains a reference to the server side cookie which is stored on the web server. So, when a user visits a website, the client’s browser sends the reference code to the web server which in turn loads the corresponding data.

Advantages of such a combination of a client side and server side cookie representing a session are:

1. The server-side cookie can contain very large amounts of data with no hassle - client-side cookies are limited in size.

2. The client-side cookie contains nothing other than a small reference code - as this cookie is passed each time someone visits a page on your site, you are saving a lot of bandwidth by not transferring large client-side cookies around.

3. Session data is much more secure - only you are able to manipulate it, as opposed to client-side cookies which are editable by all.

Usage:

session_start();

$_SESSION[‘firstName’] = “Jim”;

print $_SESSION[‘firstName’];

unset($_SESSION[‘firstName’]);

session_destroy();

As shown above, when you call session_start(), PHP will check to see if the client computer’s browser has sent a session cookie, if it did, then PHP will load the session data. Otherwise, PHP will create a new session file on the server and send an ID back to the client computer to associate it with the new file. To remove a specific value from a session, use unset() function. It is important that you should unset only specific elements of the $_SESSION array, not the $_SESSION array itself, because doing so would leave you without any way to manipulate the session data at all.

Making a curl request behind a proxy

2011-12-27T18:29:00.003+05:30

Set following additional curl options in order to make a curl request behind an http proxy:

curl_setopt($ch, CURLOPT_HTTPPROXYTUNNEL,TRUE);
curl_setopt($ch, CURLOPT_PROXYAUTH,CURLAUTH_BASIC);
curl_setopt($ch, CURLOPT_PROXY,'proxyname or proxyIP:portnumber');

PHP coding standards

2010-08-28T15:44:00.003+05:30

While we create applications in any language, we tend to follow certain coding conventions. So does this apply to creating applications in PHP as well.

Here is a list of few coding standards that i follow:
1. Use camelCaps for Variable Names
2. Use lowercase for method / function names. For functions with multiple words, an underscore is used as a separator. For e.g. function get_display_text();
3. Use class constants instead of global constants wherever possible, by using the const modifier.
4. Use descriptive variable names in for loops as well.
For e.g. $count instead of $j
for($count=0;$count < 10;$count++){
your code here
}

and many more....

It would also be great if you could also pour in your thoughts on the coding conventions you follow while writing applications in php.

Executing PHP code from a .html file

2009-09-18T11:28:00.004+05:30

You can execute PHP on a .html page by adding following line in your .htaccess file :

AddType application/x-httpd-php .html

for executing PHP on a .htm page add this line instead :

AddType application/x-httpd-php .htm

The above code will make php executable on all your .html or .htm pages

If you want to make PHP executable only on one page, you may add following line in your .htaccess file:

<Files myhtmlpage.html> AddType application/x-httpd-php .html
</Files>

The above code would make PHP executable only on myhtmlpage.html and not on all html pages.

Workaround for Maximum Script Execution time limit

2009-04-22T12:22:00.003+05:30

We all know that the default execution time of a php script is set to 30 seconds, defined by the parameter max_execution_time in php.ini file.

A simple workaround to overcome the time limitation is a call to ini_set() as :

ini_set('max_execution_time','0')   //0 = no limit

This causes the current script to be executed without any maximum time limit. I found this workaround helpful in case of sending newsletters where bulk mailing is required. Hope it is helpful to you.

Singleton Design Pattern Example in PHP

2009-04-21T14:21:00.007+05:30

Here is a sample example class that implements Singleton Design Pattern in PHP:


require_once("properties.php");
class DbConnection
{
 private $connectionId;
 
 private function __construct($dbHost,$dbUser,$dbPassword,$dbName)
 {
  $this->connectionId = 
  mysql_connect($dbHost,$dbUser,$dbPassword,true);
  if($this->connectionId)
  {
   $this->selectDatabase($dbName);
  }
  else
  {
   throw new Exception(mysql_error());
  }
 }
 
 private function selectDatabase($db)
 {
  $dbSelected = mysql_select_db($db,$this->connectionId);
  if(!$dbSelected)
  {
   throw new Exception(mysql_error());
  }
 }
 
 function __destruct()
 {
  if(is_resource($this->connectionId))
  {
   $this->closeConnection();
  }
 }
 
 public function closeConnection()
 {
  mysql_close($this->connectionId);
 }
 
 public function getResourceId()
 {
  return $this->connectionId;
 }
 
 public static function getInstance()
 {
  static $dbConnObj;
  if(!isset($dbConnObj))
  {
   $dbConnObj = new DbConnection(HOSTNAME,DB_USER,DB_PWD,DB_NAME);
  }
  return $dbConnObj;
 }
 
 public function prepareQuery($args=null)
 {
  $resourceId = $this->getResourceId();
  $args = func_get_args();
  $query = array_shift($args);
  foreach($args as $argIndex=>$param)
  {
   $args[$argIndex] = mysql_real_escape_string($param,$resourceId);
  }
  return vsprintf($query,$args);
 }
 
 public function fetchRow($query)
 {
  $recordDetails = $this->executeQuery($query);
  return $recordDetails[0]? get_object_vars($recordDetails[0]) : null;
 }
 
 public function fetchVar($query)
 {
  $recordDetails = $this->fetchRow($query);
  if(count($recordDetails)>0)
  {
   $values = array_values($recordDetails);
  }
   
  if(isset($values[0]) && $values[0]!=='')
  {
   return $values[0];
  }
 }
 
 public function executeQuery($query)
 {
  $resourceId = $this->getResourceId();
  $result = @mysql_query($query,$resourceId);
  if( preg_match("/^\\s*(insert|update|delete|replace|alter)/i",$query) ){
   $returnVal = mysql_affected_rows($resourceId); 
  }
  else{
   $resultSet = array();
   while($row = @mysql_fetch_object($result))
   {
    $resultSet[] = $row; 
   }
   $returnVal = $resultSet;
  }
  return $returnVal;
 }
}

try{
 $dbConn = DbConnection::getInstance(); 
}catch(Exception $e){
 die("
Error:".$e->getMessage());
}

Note:
1. HOSTNAME
2. DB_USER
3. DB_PWD
4. DB_NAME are constants defined in

properties.php

File uploading issue

2009-02-03T19:15:00.010+05:30

Recently, I was writing a php script for uploading files.Strangely enough, I was able to upload all common types of files i.e.*.mpeg,*.avi,*.swf files but i was unable to upload flash files.

As i was aware that the default file upload size,controlled by upload_max_filesize php.ini directive is 2MB and the default maximum size of post Data that PHP accepts, controlled by post_max_size php.ini directive is 8MB, i tried changing value of upload_max_filesize using ini_set() function to 8MB. But there was no effect of this as i found that ini_set() doesn't necessarily change all the directives.

Then as a test, i made following changes directly in php.ini file:
1. set upload_max_filesize to 8MB
2. set post_max_size to 9MB
And voila, it worked. I was able to upload flash files(.flv) as well alongwith other video file types.

Note: Files are usually POSTed to the webserver using 'multipart/form-data' encoding format.What post_max_size does is,to set the upper limit on the amount of data that a script can accept.

Hence,post_max_size is the upload_max_filesize plus the sum of the lengths of all the other fields in the form.

Finally, after checking php manual and php.net link, i figured out following rules to follow before using ini_set() function

1. Make sure that the "CHANGEABLE" attribute of the php.ini directive whose value you would like to alter, is either PHP_INI_USER OR PHP_INI_ALL. Only those directives with these "CHANGEABLE" values can be modified with ini_set() function.

2. In the above case, make changes in php.ini as mentioned above.

Internationalization using PHP - phpfreaks link

2009-01-28T15:55:00.004+05:30

Forum Link on www.phpfreaks.com about Internationalization using PHP

Internationalization using PHP

MYSQL - query to find top 10 favourite locations in each city

2009-01-27T20:38:00.003+05:30

Here's a short example of using MYSQL CASE WHEN Control flow function alongwith User defined variables

SELECT CITY,Location,Most_Popular
FROM
(
SELECT @CITY,
CASE
WHEN (@CITY=CITYNAME FIELD AND @ROWNUM < 10) THEN (@ROWNUM:=@ROWNUM+1)
WHEN (@CITY != CITYNAME FIELD) THEN @ROWNUM:=1
ELSE @ROWNUM:=10
END AS CHANGED_CITY, @CITY:=CITYNAME FIELD, D.*
FROM (SELECT @ROWNUM:=0) R, (SELECT @CITY:='0') M,
(
SELECT CITY, Location, count(UserId Field) as Most_Popular
FROM Table Names
WHERE
Field Constraints
group by CITY,Location
order by CITY,Most_Popular Desc
)D
)D1
GROUP BY CITY,CHANGED_CITY
order by CITY,Most_Popular Desc;

Thanks to Ankit for helping me out on this...

MYSQL CASE WHEN EXAMPLE

2009-01-23T19:52:00.001+05:30

Here's a short example of using CASE WHEN control flow statement for grouping users who write reviews by age group:

select CASE
WHEN ( FLOOR(datediff(CURRENT_DATE,DOB)/365) > 15 AND FLOOR(datediff(CURRENT_DATE,DOB)/365) < 25) THEN '15-25'
WHEN ( FLOOR(datediff(CURRENT_DATE,DOB)/365) > 25 AND FLOOR(datediff(CURRENT_DATE,DOB)/365) < 35) THEN '25-35'
WHEN ( FLOOR(datediff(CURRENT_DATE,DOB)/365) > 35 AND FLOOR(datediff(CURRENT_DATE,DOB)/365) < 50) THEN '35-50'
ELSE 'Above 50'
END as Age_Group,
count(*) as Reviews
FROM
Table names
WHERE
Field Constraints
group by Age_Group;

NOTE:
DOB:Date of Birth field

Dear Readers

2009-01-23T11:47:00.001+05:30

Finally a blog to pen down my daily coding work...!! I have been thinking of setting up a blog for quite a long time where in i could write just about anything new that i keep learning about LAMP Stack and of course!! to keep a track of my coding tricks.....Keep watching this space for more posts...