unset() sets a variable to “undefined” while unlink() deletes a file we pass to it from the file system.
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:
requirewill produce a fatal error (E_COMPILE_ERROR) and stop the scriptincludewill only produce a warning
Clear the browser cache of CSS or JavaScript Using PHP
Other than caching every hour, or every week, you may cache according to file data.
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<script src="js/my_script.js?v=<?=md5_file('js/my_script.js')?>"></script> |
or use file modification time:
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<script src="js/my_script.js?v=<?=filemtime('js/my_script.js')?>"></script> |
or use file modification every hour:
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<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; } } } } |
PHP: fopen error handling
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 } |
PHP function to make slug (URL string)
Note: from WordPress
Use it like this:
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echo sanitize('testing this link'); |
Code:
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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 $title; } |
How can we get the IP address of the client ?
What’s the difference between the include() and require() functions?
They both include a specific file but on require the process exits with a fatal error if the file can’t be included, while include statement may still pass and jump to the next step in the execution.
Current Site URL – Codeigniter
To get host url of current server simply replace
application\config\config.php
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$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'] = $sysurl; |
Random String PHP
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function generateRandomString($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(); |