Setup Cron Job with PHP without crontab that runs every minute.

Cron job is scheduling some tasks with in regular interval on server.To setup cron job we must know about the cron tab commonds and shell access to remote server. generelly every hosting providers provide some programs like cPanel. Here we run a cron job that runs every mintues automatically without cron tab unix / linux demon or without any externel progams.

Generelly Cron job will run atleast four hours gap on cPanel or Plesk ,so it is not possible to setup cron job every minute unless you have crontab demon on server , SSH account on server. Here we write a simple php script that calls itself at every minute.

Remmber this cron job runs with curl php extension.

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//This function runs with curl extension that calls or open remote file.
function call_remote_file($url){
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);   
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_exec($ch);
curl_close($ch);
}
 
function do_somework(){
//This function to run every minutes
@mail('mahesh@gmail.com','cron job','cron runned');
}
set_time_limit(0); 
// some web hosts will have only 30 sec max execution time so we keep it unlimited time
// this function only runs if safe mode is off
$url="http://www.maheshchari.com/cronjob.php"; //it is the script that runs exactly every minutes
call_remote_file($url);
do_somework();//in mean time run some work
sleep(60); // wait the script for 60 seconds or every minute
call_remote_file($url); // call this script itself after a minute
// This process continues every minute

To stop this cron job simple remove the file from server.

With this script we don’t need

• SSH /SFTP account
• No need of learning cron tab commonds.
• No script php exec permissions.
• No need to turn off php safe mode.

Download Demo

Popularity: 8% [?]

Check given link is real working

We see the most online enquiry ,guest books,help ticket system asks for the web address of the guest ,mostly of them are optional.i think in some case it required to given web address or page link really exists or not.Here we learn how to find the given link or url is really exists or it fake.For this we use simple fsocketopen function. we make a simple function that given below.It only check HTTP links.not HTTPS,FTP protocal urls. Remember the link parameter must be a valid web url address.we can do it with CURL php extension functions.but in case if it not available it won’t work. so given function is core PHP function.

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<?php 
function isRealLink($link){
 return (boolean)@fsockopen($link, 80, $errno, $errstr, 30);
}
?>

Popularity: 25% [?]

How to check browser cookie enabled with php javascript

Cookies are typically used by web servers to perform functions such as tracking your visits to websites, enabling you to log in to sites, and storing your shopping cart. Cookies can be used to interaction between Javascript and Server Side  Scripts like PHP.Cookies also used to transfer small amount of data between one page to other pages via HTTP headers .If user disables this cookies or user’s browser won’t support the interaction between JS and PHP fails.So we must ensure user must enable these Cookies.

In this article,we check the user’s browser Cookie enabled or not.This can be achieved by both client side Javascript and Server Side Script.

Checking with Javascript

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if (navigator.cookieEnabled == 0) {
  alert("You need to enable cookies for this site to load properly!");
}

Checking with PHP

If user disables Javascript we fail to check the Cookie enabled or not.So we check on the server side also.below PHP snippet check the Cookie enabled or not.

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function check_cookie(){
	if (setcookie("test", "test", time() + 360))
	{
		if (isset (@$_COOKIE['test']))
		{
			return true;
		}
	}
return false;
}

Popularity: 29% [?]

How to export tabular data from php / mysql to MS excel

In this article, I show how to build a PHP Web application that uses these Excel formats to export the contents of a mysql database table or array to an simple Excel spreadsheet.Microsoft Office 2003 for the Microsoft Windows® make simple Excel as simple xml data with predefined XSLT stylesheet. It also supports HTML table data and delemiter support.Here we take these two advantages.

First technique is just simple as we fetch the data from source like arrays or mysql table in HTML table,force the browser to download the file as xls file.When download completed we can open with MS Excel.

Code I

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<?php /* 
This example demonstrates 
how to convert PHP array data to MS Excel 2003 data to download <br>
user data base.
Here we create a simple HTML tabler data and we force the web browser as stream data
instead we simply displaying HTML table
thats all
 */
$data_headers=array('First Name','Last Name','Date of Birth');
$data_array[]=array('Mahesh','Chari','25-08-1983');
$data_array[]=array('Chari','Mahesh','25-08-1980');
$data_array[]=array('Guggilla','Mahesh','25-08-1970');
$data_array[]=array('Mahesh','Guggilla','21-08-1985');
$data_array[]=array('Mahesh Chari','Guggilla','20-08-1950');
$data_array[]=array('Chari','Guggilla','25-08-1950');
// here we prepare a simple HTML table string
$html_string='<table>';
$html_string.='<tr><td>'.implode('</td><td>',$data_headers).'</td></tr>';
	foreach($data_array as $k=>$v){
		$html_string.='<tr><td>'.implode('</td><td>',$v).'</td></tr>';
	}
$html_string.='</table>';
//make time dependent xls name that is always unique
$xlsfile = "excel_example".date("m-d-Y-hiA").".xls";
//stop the browser displaying the HTML table displaying
//force the browser to download as xcel document
//if you make comment below two lines as php comments ,you see a simple HTML table
header('Content-type: application/vnd.ms-excel');
header("Content-Disposition: attachment; filename=$xlsfile");
 
print  $html_string;?>

Download above Example script

Second technique is just simple as we fetch the data from source like arrays or mysql table in simple tab delimitted text ,force the browser to download the file as xls file.When download completed we can open with MS Excel.

Code II

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<?php 
/* 
This example demonstrates 
how to convert PHP array data to MS Excel 2003 data to download <br>
user data base.
Here we create a simple text format like CSV with a delimiter \t tab and new line delimiter for rows
thats all
 */
$data_headers=array('First Name','Last Name','Date of Birth');
$data_array[]=array('Mahesh','Chari','25-08-1983');
$data_array[]=array('Chari','Mahesh','25-08-1980');
$data_array[]=array('Guggilla','Mahesh','25-08-1970');
$data_array[]=array('Mahesh','Guggilla','21-08-1985');
$data_array[]=array('Mahesh Chari','Guggilla','20-08-1950');
$data_array[]=array('Chari','Guggilla','25-08-1950');
// here we prepare a simple  \t delimetered text format 
$delim_string='';
$delim_string.=implode("\t",$data_headers)."\n";
	foreach($data_array as $k=>$v){
	$delim_string.=implode("\t",$v)."\n";
	}
 
//make time dependent xls name that is always unique
$xlsfile = "excel_example".date("m-d-Y-hiA").".xls";
//stop the browser displaying the data as text
//force the browser to download as xcel document
header('Content-type: application/vnd.ms-excel');
header("Content-Disposition: attachment; filename=$xlsfile");
 
print $delim_string;
 
?>

Download above Example script

To make advanced excel format like colors,cell formats,work book you can code with PEAR excel package.some opensource packages are available. please refer below for advanced excel convertion.

• http://code.google.com/p/php-excel/
• http://pear.php.net/package/Spreadsheet_Excel_Writer/

Download above Examples scripts

Popularity: 28% [?]

Long URL Vs Short URL

We know the fact that present content available in the internet is from web applications not web site!  We see many advanced Server side scripts like PHP, Perl, and Java etc. that generates most of the dynamic content on the web.
For example http://www.wikipedia.org/ is a largest data collection or knowledge base. This data can be found through URL on the web. So URL is the key point to dynamic content. Generally we do this with a dynamic parameters append to URL and fetch the data from the server according to parameter. We can also use it for short time, like user activation, forgot password, reset password. So we have some information about URL.

Here we discuss about the length of the URL of the web site. As web developer we ensure that our web application work in all web browsers, all plat forms and all server. Off course it is difficult to ensure it, but we work at least an environment like lowest version of the browser, server, and operating system.

Dyamic URL

Example URL:
http://www.maheshchari.com/products/items.php?id=x&model=y&variety=z
http://www.maheshchari.com/activatepage.php?username=x&email=y&reset=z ….etc

Disadvantages

• the length of the URL must work at least IE6, that accepts max length of 2083.
• Some servers like Apache sends HTTP 413 error, not sure it depends for different versions and plat forms.Long URLs usually break when quoted in an e-mail message, and then don’t work.
• In the above URL the data x, y, z vary to different situations, so it may exceed limit.
• It leads some times as security issue.
• user can’t remember and type the URL

Best practices

• make ensure the data is less.
• user URL shortening web services.
• encode number of parameters to single parameters.

To make small URL with PHP see how we implement it below code

encoding to Short URL

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//making uniform data length link
//we encrypt user data to base 64 codeformat and urlencode format
$param=urlencode(base64_encode('username=x&email=y&reset=z'));
$url='http://www.websitename.com/activate.php?param='.$param;
echo $url;
//output is:http://www.websitename.com/activate.php?param=dXNlcm5hbWU9eCZlbWFpbD15JnJlc2V0PXo%3D 
//we can also  use available url shortening web services like tiny.url ..etc
//they provide like tinyurl.com/xeuess

Decoding to long URL

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// decoding and parse to GET method
$getparam=$_GET['param'];
$decoded_param=base64_decode(urldecode($getparam));
echo $decoded_param;
//output :username=x&email=y&reset=z
//we delete this $_GET['param']
//re assign global $_GET variable
parse_str($decoded_param,$_GET);
echo $_GET['username'];
//output is: x

Static URL

Example URL

http://www.maheshchari.com/articles/how-to-become-a-rich-man-with-in-one-day-by-author-example/

http://www.maheshchari.com/articles/worlds-largest-mountains-in-india-and-other-countries-polls-for-2000/

It is a well-known fact nowadays that without SEO a Web site stands many chances of not being indexed by search spiders. that results poor conversion rate.my colleague who is SEO expert had this type issue in past, that he used like above URL in his SEO or search engine optimization as it gives more chances of indexing in most search engine. but result is poor.but it wrong since he gave full URL and the page content is not much relevant to this URL. it may leads some times penalize or some times it may be spammed.

Best practices

• Keep URL small as possible as less than 5 to 6 words and make it for human readable not for bots
• Keep URL most relevant to the content.
• Keep highest keyword starting position even though grammatical mistake.
• There is some online web services available that suggests URL according to the content.
• Use URL shortening web services while campaign .

Popularity: 11% [?]

Regular Expressions Reference or Cheat Sheet

The regular expression, as a pattern, can match all kinds of text strings helping our web application validate, compare, sanitize data, compute, decide , format , data extraction  etc. It can do simple or very complex string manipulations. The list of possibilities is enormous when it comes to what you can achieve using regular expressions.Below table shows a quick referece to basic syntax , definations and examlple.

Popularity: 22% [?]

How to stop the web browser caching the document

All web documents, media and other web resources retrieved by a Web browser, are often saved, or cached, locally on the user’s hard drive. The next time that media or web resources is requested the Web browser may load the file from the cache instead of downloading it over the internet. This might be desirable for a some web document content doesn’t change often but undesirable for documents are updated frequently with new content or information.
All web servers sends to the browser with some basic information about the document before it sent .in the above example we can see some of them.for full details please refer here . we can use this server side headers to prevent browser caching .we learn here only PHP related headers.

preventing browser cache with javascript.

Here i am showing basic jQuery plugin that appends a random time to each links in document.

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(function($){
	$.fn.nocachelink=function(options){
	//itereate trough each element in given element collection
		return this.each(function(){
			var href=$(this).attr('href');
			if(href.lastIndexOf('?')!=-1){ //if query string is set or not for link
			href=href+'?'+new Date().getTime();
			}else{
			href=href+'&'+new Date().getTime();
			}
			$(this).attr('href',href); // update new href attribute
		});
	}
})(jQuery);

An example how to use it

$().ready(function(){
	$('.nocache').nocachelink();
});

preventing browser cache with meta tags.

to prevent cache by means of html meta tags add following tags to document head section.

<meta http-equiv="Pragma" content="no-cache">
<meta http-equiv="Expires" content="-1">
<meta http-equiv="CACHE-CONTROL" content="NO-CACHE">

preventing browser cache with server side headers.

we can also use HTTP headers by php also as below,remember you must add this lines to start of code.

//  @-silenced or error suppress operater
	@header( 'Expires: Wed, 11 Jan 1984 05:00:00 GMT' );
	@header( 'Last-Modified: ' . gmdate( 'D, d M Y H:i:s' ) . ' GMT' );
	@header( 'Cache-Control: no-cache, must-revalidate, max-age=0' );
	@header( 'Pragma: no-cache' );

preventing browsers cache with ajax calls.

we can also set headers with ajax response headers.

preventing browser cache with other methods.

By default all browser don’t cache SSL layered documents.
below example document won’t cached by browsers.

https://www.yourdomain.com

Popularity: 11% [?]

A simple function to find the real IP address of the client with php

As the internet growing as long as spamming,hacking,fishing,bots also increasing,there by normal user can easly decepted by with them. in many security application we need to find the real ip address to ban or record the ip related activities.here we use small function that returns and modify the PHP global remote address variable.

Usually we’ll use $_SERVER['REMOTE_ADDR'] to get clients IP address. But this doesn’t return the real IP address all time. Basically when someone using PROXY that valiable returns proxy IP the client using. So here’s a function you can use to detect real ip address of client. Here are extra Server variable which might be available to determine the exact IP address of the client’s machine in PHP, they are HTTP_CLIENT_IP and HTTP_X_FORWARDED_FOR

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function real_ip(){
	if(isset($_SERVER['HTTP_X_FORWARDED_FOR'])){
		$_SERVER['REMOTE_ADDR']=$_SERVER['HTTP_X_FORWARDED_FOR'];
	}elseif(isset($_SERVER['HTTP_X_REAL_IP']){
		$_SERVER['REMOTE_ADDR']=$_SERVER['HTTP_X_REAL_IP'];
	}
return $_SERVER['REMOTE_ADDR'];
}

Popularity: 10% [?]

how to find the given request from ajax with php

In my recent project ,i have to restrict a page from direct accessing from browser with typing address on browser .this page must only accessible with ajax only.thank god there is a solution to find this with php server global variable that works with php5.then i made it a simple following function.

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function is_Ajax() {
return (isset($_SERVER['HTTP_X_REQUESTED_WITH']) &&
($_SERVER['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest'));
}

Popularity: 8% [?]

image rollover effect with css background image

Here we use basic css back ground image to get rollover effect.the logic is simple and we can find it in comments in script itself.

• we create a empty link
• set back ground as test1.jpg and display to block and height and width to 150px.
• build a suido selctor hover to link and set back ground image to test2.jpg
• this works even javascript disabled browsers also

Download Script

image-rollover-css

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<html>
<head>
<title>image rollover with css</title>
<style type="text/css">
<!--
#imagerollover a {
	background-image: url(test2.JPG);
	display: block;
	background-repeat: no-repeat;
	height: 150px;
	width: 150px;
}
#imagerollover a:hover{
	background-image: url(test1.JPG);
}
-->
</style>
</head>
<body>
<div id="imagerollover"><a href="#test">&nbsp;</a></a></div>
</body>
</html>

Download Script

image-rollover-css

Popularity: 10% [?]