How to Detect a URL / Hyperlink within text - using PHP

By: irshido | Jul 18, 2011 | In: How To | Likes: 2 | Views:2426

PHP comes with numerous built in functions that come handy in many instances. 

In the below example, we are making use of the preg_match() and preg_replace() funtions that come built in with PHP, to detect and display URL's or Hyperlinks within text. Detecting URL's within text & displaying them is one of the essential things any web developer should be aware of. 

Lets take the below paragraph for example:

"The aim of http://www.TechDesk.info is to help everyone learn the latest trends in IT and help them familiarize themselves.."

as you can see there is a a url on the 1st line but it is displayed as normal text. The intention of this tutorial is to detect that url from the text and display it as a hyperlink using PHP

Example 01:

Checking for URL's on text Saved in a Variable

 

// define a variable that will hold characters of a URL

$hyperlink = "/(http|https|ftp|ftps)\:\/\/[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,4}(\/\S*)?/";  

//Store the text containing the URL's in the variable '$para' 

$para ="The aim of http://www.TechDesk.info is to help everyone learn the latest trends in IT and help them familiarize themselves..";

$para = preg_replace($hyperlink, '<a href="'.$url[0].'" rel="nofollow">'.$url[0].'', $para); 

//Check if there is a url in the post using the PHP preg_match function

if (preg_match($hyperlink, $para, $url)) {

// If a URL match is found, display it as a URL

$para = preg_replace($hyperlink, ''.$url[0].'', $para); 

}

// Display the results 

echo "$para" ;

?>

Example 02:

Checking for URL's from results retrieved from a MySQL database

 <?php

//define an empty variable 

$para ="";

// define a variable that will hold characters of a URL

$hyperlink = "/(http|https|ftp|ftps)\:\/\/[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,4}(\/\S*)?/";  

// Connect to the database

$db_host = "localhost";

$db_username = "user01";

$db_pass = "password123";

$db_name = "test_db";

@mysql_connect("$db_host","$db_username","$db_pass") or die ("could not connect to mysql");

@mysql_select_db("$db_name") or die ("Database connection failure! ");

// after connecting to the database

//select the row containing the text from the table ‘test_tbl’

$sql = mysql_query("SELECT paragraph  FROM test_tbl "); /

while($row = mysql_fetch_array($sql)){

      // save the result in a variable

       $para = $row["paragraph "];

          // Check if there is a url in the post

         if (preg_match($hyperlink, $para, $url)) {

         // make the urls found within the text as hyper links

         $para = preg_replace($hyperlink, '<a href="'.$url[0].'" rel="nofollow">'.$url[0].'</a>', $para);

          }

}

// Display the results 

echo "$para" ;

?>

 

 

 

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