PHP - Code Snippets

What’s the difference between unset() and unlink() ?

unset() sets a variable to “undefined” while unlink() deletes a file we pass to it from the file system.

How can we get the IP address of the client ?

There are many options but the easiest solution is

1	$_SERVER["REMOTE_ADDR"];

Difference between require, include, require_once and include_once ?

It is possible to insert the content of one PHP file into another PHP file (before the server executes it), with the include or require statement.

The include and require statements are identical, except upon failure:

require will produce a fatal error (E_COMPILE_ERROR) and stop the script
include will only produce a warning

What’s the difference between the include() and require() functions?

They both include a specific file but on require the process exits with a fatal error if the file can’t be included, while include statement may still pass and jump to the next step in the execution.

Clear the browser cache of CSS or JavaScript Using PHP

Snippets

Other than caching every hour, or every week, you may cache according to file data.

1	<script src="js/my_script.js?v=<?=md5_file('js/my_script.js')?>"></script>

or use file modification time:

1	<script src="js/my_script.js?v=<?=filemtime('js/my_script.js')?>"></script>

or use file modification every hour:

1	<script type="text/javascript" src="js/myscript.js?v=<?php echo date('YmdHis'); ?>"></script>

or Using Javascript

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function reloadScripts(toRefreshList/* list of js to be refresh */, key /* change this key every time you want force a refresh */) {

var scripts = document.getElementsByTagName('script');

for(var i = 0; i < scripts.length; i++) {

var aScript = scripts[i];

for(var j = 0; j < toRefreshList.length; j++) {

var toRefresh = toRefreshList[j];

if(aScript.src && (aScript.src.indexOf(toRefresh) > -1)) {

new_src = aScript.src.replace(toRefresh, toRefresh + '?k=' + key);

// console.log('Force refresh on cached script files. From: ' + aScript.src + ' to ' + new_src)

aScript.src = new_src;

}

Current Site URL – Codeigniter

Snippets

To get host url of current server simply replace

application\config\config.php

1	$config['base_url'] = '';

with

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// Home URL

$sysurl = ((isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] == "on") ? "https" : "http");

$sysurl .= "://" . $_SERVER['HTTP_HOST'];

$sysurl .= str_replace(basename($_SERVER['SCRIPT_NAME']), "", $_SERVER['SCRIPT_NAME']);

$config['base_url'] = $sysurl;

PHP: fopen error handling

Snippets

You should first test the existence of a file by file_exists().

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try

{

$fileName = 'uploads/Team/img/'.$team_id.'.png';

if ( !file_exists($fileName) ) {

throw new Exception('File not found.');

}

$fp = fopen($fileName, "rb");

if ( !$fp ) {

throw new Exception('File open failed.');

}

$str = stream_get_contents($fp);

fclose($fp);

// send success JSON

} catch ( Exception $e ) {

// send error message if you can

}

or simple solution without exceptions:

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$fileName = 'uploads/Team/img/'.$team_id.'.png';

if ( file_exists($fileName) && ($fp = fopen($fileName, "rb"))!==false ) {

$str = stream_get_contents($fp);

fclose($fp);

// send success JSON

}

else

{

// send error message if you can

}

Random String PHP

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function generateRandomString($length = 10) {

$characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';

$charactersLength = strlen($characters);

$randomString = '';

for ($i = 0; $i < $length; $i++) {

$randomString .= $characters[rand(0, $charactersLength - 1)];

}

return $randomString;

}

Output the random string with the call below:

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// Echo the random string.

// Optionally, you can give it a desired string length.

echo generateRandomString();

PHP function to make slug (URL string)

Snippets

Note: from WordPress

Use it like this:

1	echo sanitize('testing this link');

Code:

//taken from wordpress
function utf8_uri_encode( $utf8_string, $length = 0 ) {
    $unicode = '';
    $values = array();
    $num_octets = 1;
    $unicode_length = 0;

$string_length = strlen( $utf8_string );
    for ($i = 0; $i < $string_length; $i++ ) {

$value = ord( $utf8_string[ $i ] );

if ( $value < 128 ) {
            if ( $length && ( $unicode_length >= $length ) )
                break;
            $unicode .= chr($value);
            $unicode_length++;
        } else {
            if ( count( $values ) == 0 ) $num_octets = ( $value < 224 ) ? 2 : 3;

$values[] = $value;

if ( $length && ( $unicode_length + ($num_octets * 3) ) > $length )
                break;
            if ( count( $values ) == $num_octets ) {
                if ($num_octets == 3) {
                    $unicode .= '%' . dechex($values[0]) . '%' . dechex($values[1]) . '%' . dechex($values[2]);
                    $unicode_length += 9;
                } else {
                    $unicode .= '%' . dechex($values[0]) . '%' . dechex($values[1]);
                    $unicode_length += 6;
                }

$values = array();
                $num_octets = 1;
            }
        }
    }

return $unicode;
}

//taken from wordpress
function seems_utf8($str) {
    $length = strlen($str);
    for ($i=0; $i < $length; $i++) {
        $c = ord($str[$i]);
        if ($c < 0x80) $n = 0; # 0bbbbbbb
        elseif (($c & 0xE0) == 0xC0) $n=1; # 110bbbbb
        elseif (($c & 0xF0) == 0xE0) $n=2; # 1110bbbb
        elseif (($c & 0xF8) == 0xF0) $n=3; # 11110bbb
        elseif (($c & 0xFC) == 0xF8) $n=4; # 111110bb
        elseif (($c & 0xFE) == 0xFC) $n=5; # 1111110b
        else return false; # Does not match any model
        for ($j=0; $j<$n; $j++) { # n bytes matching 10bbbbbb follow ?
            if ((++$i == $length) || ((ord($str[$i]) & 0xC0) != 0x80))
                return false;
        }
    }
    return true;
}

//function sanitize_title_with_dashes taken from wordpress
function sanitize($title) {
    $title = strip_tags($title);
    // Preserve escaped octets.
    $title = preg_replace('|%([a-fA-F0-9][a-fA-F0-9])|', '---$1---', $title);
    // Remove percent signs that are not part of an octet.
    $title = str_replace('%', '', $title);
    // Restore octets.
    $title = preg_replace('|---([a-fA-F0-9][a-fA-F0-9])---|', '%$1', $title);

if (seems_utf8($title)) {
        if (function_exists('mb_strtolower')) {
            $title = mb_strtolower($title, 'UTF-8');
        }
        $title = utf8_uri_encode($title, 200);
    }

$title = strtolower($title);
    $title = preg_replace('/&.+?;/', '', $title); // kill entities
    $title = str_replace('.', '-', $title);
    $title = preg_replace('/[^%a-z0-9 _-]/', '', $title);
    $title = preg_replace('/\s+/', '-', $title);
    $title = preg_replace('|-+|', '-', $title);
    $title = trim($title, '-');

return $title;
}

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//taken from wordpress

function utf8_uri_encode( $utf8_string, $length = 0 ) {

$unicode = '';

$values = array();

$num_octets = 1;

$unicode_length = 0;

$string_length = strlen( $utf8_string );

for ($i = 0; $i < $string_length; $i++ ) {

$value = ord( $utf8_string[ $i ] );

if ( $value < 128 ) {

if ( $length && ( $unicode_length >= $length ) )

break;

$unicode .= chr($value);

$unicode_length++;

} else {

if ( count( $values ) == 0 ) $num_octets = ( $value < 224 ) ? 2 : 3;

$values[] = $value;

if ( $length && ( $unicode_length + ($num_octets * 3) ) > $length )

break;

if ( count( $values ) == $num_octets ) {

if ($num_octets == 3) {

$unicode .= '%' . dechex($values[0]) . '%' . dechex($values[1]) . '%' . dechex($values[2]);

$unicode_length += 9;

} else {

$unicode .= '%' . dechex($values[0]) . '%' . dechex($values[1]);

$unicode_length += 6;

}

$values = array();

$num_octets = 1;

}

return $unicode;

}

//taken from wordpress

function seems_utf8($str) {

$length = strlen($str);

for ($i=0; $i < $length; $i++) {

$c = ord($str[$i]);

if ($c < 0x80) $n = 0; # 0bbbbbbb

elseif (($c & 0xE0) == 0xC0) $n=1; # 110bbbbb

elseif (($c & 0xF0) == 0xE0) $n=2; # 1110bbbb

elseif (($c & 0xF8) == 0xF0) $n=3; # 11110bbb

elseif (($c & 0xFC) == 0xF8) $n=4; # 111110bb

elseif (($c & 0xFE) == 0xFC) $n=5; # 1111110b

else return false; # Does not match any model

for ($j=0; $j<$n; $j++) { # n bytes matching 10bbbbbb follow ?

if ((++$i == $length) || ((ord($str[$i]) & 0xC0) != 0x80))

return false;

}

return true;

}

//function sanitize_title_with_dashes taken from wordpress

function sanitize($title) {

$title = strip_tags($title);

// Preserve escaped octets.

$title = preg_replace('|%([a-fA-F0-9][a-fA-F0-9])|', '---$1---', $title);

// Remove percent signs that are not part of an octet.

$title = str_replace('%', '', $title);

// Restore octets.

$title = preg_replace('|---([a-fA-F0-9][a-fA-F0-9])---|', '%$1', $title);

if (seems_utf8($title)) {

if (function_exists('mb_strtolower')) {

$title = mb_strtolower($title, 'UTF-8');

}

$title = utf8_uri_encode($title, 200);

}

$title = strtolower($title);

$title = preg_replace('/&.+?;/', '', $title); // kill entities

$title = str_replace('.', '-', $title);

$title = preg_replace('/[^%a-z0-9 _-]/', '', $title);

$title = preg_replace('/\s+/', '-', $title);

$title = preg_replace('|-+|', '-', $title);

$title = trim($title, '-');

return $title;

}

Include all files with in the folder

Snippets

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foreach (glob("assets/lib/*.php") as $filename) {

include $filename;

}