Hello coders,

Here’s a function that validates a username. It can be used when you have a register form and the user should enter a valid username (that shouldn’t contain illegal characters).

<?php
function validate_username($username)
{
$check = eregi_replace('([a-zA-Z0-9_]+)', "", $username);

if(empty($check))
	{
	return true;
	}
	else
	{
	return false;
	}
}

$username = 'john_jones';

$validator = validate_username($username);

if($validator)
{
echo 'The username is valid.';
}
else
{
echo 'The username should contain only letters, numbers and underscores.';
}
?>

If you use ‘john#_$%jones’ as an username the function will return ‘false’.

If you have any comments / suggestions feel free to post them.

This function generates random passwords. It’s useful when you have to reset someone’s account or when you create accounts that need a default password.

<?php
/*
Credits: Bit Repository

http://www.bitrepository.com/web-programming/php/generating-a-random-password.html

*/
function generate_random_password($chars = 7, $type = '')
{
$letters_array = range('a','z');
$numbers_array = range(1,9);

srand((float) microtime() * 10000000); // if PHP Version < 4.2.0 

if($type == 'letters')
{
$array = $letters_array;
}
else if($type == 'numbers')
{
$array = $numbers_array;
}
else
{
$array = array_merge($letters_array, $numbers_array);
}

$rand_keys = array_rand($array, $chars);

$password = '';

foreach($rand_keys as $key)
	{
	$password .= $array[$key];
	}

return $password;
}

$password = generate_random_password();

// Outputs a 7 characters password (default)
echo $password;

$password = generate_random_password(10);

// Outputs a 10 characters password
echo $password;
?>

$new_password = generate_random_password(10,'numbers');

// Outputs a numeric password containing only numbers.
echo $new_password;

NOTE: You can add ‘letters’ for the second parameter if you want to have only letters in the password.

Read the rest of this entry…

Hi,

This function takes a regular phrase and formats it into a seo friendly string which can be part of an URL.

<?php
function friendly_seo_string($string, $separator = '-')
{
$string = trim($string);

$string = strtolower($string); // convert to lowercase text

// Recommendation URL: http://www.webcheatsheet.com/php/regular_expressions.php

// Only space, letters, numbers and underscore are allowed

$string = trim(ereg_replace("[^ A-Za-z0-9_]", " ", $string));

/*

"t" (ASCII 9 (0x09)), a tab.
"n" (ASCII 10 (0x0A)), a new line (line feed).
"r" (ASCII 13 (0x0D)), a carriage return. 

*/

$string = ereg_replace("[ tnr]+", "-", $string);

$string = str_replace(" ", $separator, $string);

$string = ereg_replace("[ -]+", "-", $string);

return $string;
}

$str = friendly_seo_string('Lorem Ipsum is simply dummy text.');

// Outputs: lorem-ipsum-is-simply-dummy-text
echo $str;
?>

This string can be added to a friendly URL like this:

http://www.yourdomain.com/info/lorem-ipsum-is-simply-dummy-text.html

Recommendation URLs:

http://www.webcheatsheet.com/php/regular_expressions.php

http://www.php.net/manual/function.ereg-replace.php

Greetings,

Let’s suppose you have a mysql database and you need to update only a part of a field’s value, not all.

This can be done using the following query:

UPDATE `table` SET `field` = REPLACE(`field`, "old_string", "new_string");

Here’s how it will look like in a PHP Code:

<?php
$db_host = 'db_host'; // usually localhost
$db_user = 'db_username';
$db_pass = 'db_password';
$db_name = 'db_name';

$db = mysql_connect($db_host, $db_user, $db_pass)
or die ("Unable to connect to Database Server.");

mysql_select_db ($db_name, $db) or die ("Could not select database.");

$table_name = 'lists';

$table_field_name = 'category';

$initial_string = 'man';
$new_string = 'boy';

$query = "UPDATE `".$table_name."`
SET `".$table_field_name."`=REPLACE(`".$table_field_name."`,
'".$initial_string."', '".$new_string."');";

/* NOTE: You can add conditions to this query in case you want to update
a specific field ID like this:

UPDATE `table_name`
SET `field_name` = REPLACE(`field_name` "old_string", "new_string")
where field_id='id_number_here';
*/

$sql_query = mysql_query($query) or die(mysql_error());

if($sql_query)
{
echo 'Table ' .$table_field_name. ' has been successfully updated.';
}
?>

Feel free to post any comments regarding this tutorial.

Hi,

In this tutorial we will show you how to show alternate colors between (table) rows. They are nice to use in a site’s design.

First let’s define each color:

<?php
// Define colors here

$color_one = '#FFFFFF';
$color_two = '#E6F2F7';

Let’s build our sample array.

$array = array('apple','pine','strawberry',
                    'pear','banana', 'cranberry','kiwifruit');

We will use a variable that will increment with each loop:

$i = 1; // starting value
?>

Let’s output our values in table rows:

<!-- Table with alternate colors -->
<table width="100%" cellspacing="0">

How we will determine which color to show for each row?

While looping trough the array, we will check if the variable $i is an either an odd or an even number. We will determine this by checking if ($i / 2) results in an integer. If it is, then $i is even ($color_one) . Otherwise, it is odd ($color_two).

<?php
foreach($array as $value)
{
/*
Check if ($i / 2) is an integer and determine which color to show.
We will divide the number by 2
*/

$color = (is_int($i / 2)) ? $color_one : $color_two;
?>

<tr>
<td bgcolor="<?=$color?>"><?=$value?></td>
</tr>

<?php
$i++; // Increment $i
}
?>

</table>

Here’s the complete code:

<?php
// Define colors here

$color_one = '#FFFFFF';
$color_two = '#BBCCED';

$array = array('apple','pine','strawberry',
                    'pear','banana', 'cranberry','kiwifruit');

$i = 1;

?>

<!-- Table with alternate colors -->

<table width="100%" cellspacing="0">
<?php
foreach($array as $value)
{
/*
Check if ($i / 2) is an integer and determine which color to show.
We will divide the number by 2
*/

$color = (is_int($i / 2)) ? $color_one : $color_two;
?>
<tr>
<td bgcolor="<?=$color?>"><?=$value?></td>
</tr>
<?php
$i++; // Increment $i
}
?>
</table>

The output will look like this:


You can use this in any loop (for, foreach, while). Make sure you have a variable that is incrementing with each row so you can determine the alternate color.

Hello,

In this short tutorial we will learn how to enable the mod_rewrite module in Apache Server.

Step 1
Locate the folder where apache is installed (in localhost is usually in: C:Program FilesApache Software FoundationApache2.2). Find the folder “conf”. You will find in it the file: httpd.conf.

Step 2
Find the line #LoadModule rewrite_module modules/mod_rewrite.so. Uncomment it so it will look like this:

LoadModule rewrite_module modules/mod_rewrite.so

Look for #AddModule mod_rewrite.c and uncomment it as well.

AddModule mod_rewrite.c

In the same file search for:

<Directory />
Options FollowSymLinks
AllowOverride None
</Directory>

and replace it with:

<Directory />
Options FollowSymLinks
AllowOverride All
</Directory>

You may have many other attributes between the ‘Directory’ tags. Make sure that AllowOverride is set to ‘All’.

Save the new httpd.conf and restart Apache.

Good luck!

This snippet can help you to get the extension of a filename:

<?php
... some code here ...
// Filename
$filename = 'public_html/root/internet.gif';
// Extension
$ext = strrchr($filename, ".");
echo $ext; // will return ".gif"
?>

Check if a string is numeric or not.

<?php
function validate_number($string)
{
if(is_numeric($string))
	{
	return true;
	}
	else
	{
	return false;
	}
}
?>

This function checks if an email address is valid or not. For example it is very useful if you have to validate a HTML form where someone should enter a real email address.

function ValidateEmail($email)
{
/*
(Name) Letters, Numbers, Dots, Hyphens and Underscores
(@ sign)
(Domain) (with possible subdomain(s) ).
Contains only letters, numbers, dots and hyphens (up to 255 characters)
(. sign)
(Extension) Letters only (up to 10 (can be increased in the future) characters)
*/

$regex = '/([a-z0-9_.-]+)'. # name

'@'. # at

'([a-z0-9.-]+){2,255}'. # domain & possibly subdomains

'.'. # period

'([a-z]+){2,10}/i'; # domain extension 

if($email == '') {
	return false;
}
else {
$eregi = preg_replace($regex, '', $email);
}

return empty($eregi) ? true : false;
}

$email = 'name@domain.com'; 

// will return true, since it matches the regex

if(ValidateEmail($email))
{
echo ''.$email.' is a valid e-mail address.';
}
else
{
echo ''.$email.' is not a valid e-mail address.';
}