friendica/src/Util/Strings.php

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<?php
/**
* @file src/Util/Strings.php
*/
namespace Friendica\Util;
/**
* @brief This class handles string functions
*/
class Strings
{
/**
* @brief Generates a pseudo-random string of hexadecimal characters
*
* @param int $size
* @return string
*/
public static function getRandomHex($size = 64)
{
$byte_size = ceil($size / 2);
$bytes = random_bytes($byte_size);
$return = substr(bin2hex($bytes), 0, $size);
return $return;
}
/**
* This is our primary input filter.
*
* The high bit hack only involved some old IE browser, forget which (IE5/Mac?)
* that had an XSS attack vector due to stripping the high-bit on an 8-bit character
* after cleansing, and angle chars with the high bit set could get through as markup.
*
* This is now disabled because it was interfering with some legitimate unicode sequences
* and hopefully there aren't a lot of those browsers left.
*
* Use this on any text input where angle chars are not valid or permitted
* They will be replaced with safer brackets. This may be filtered further
* if these are not allowed either.
*
* @param string $string Input string
* @return string Filtered string
*/
public static function removeTags($string)
{
return str_replace(["<", ">"], ['[', ']'], $string);
}
/**
* @brief Use this on "body" or "content" input where angle chars shouldn't be removed,
* and allow them to be safely displayed.
* @param string $string
*
* @return string
*/
public static function escapeTags($string)
{
return htmlspecialchars($string, ENT_COMPAT, 'UTF-8', false);
}
/**
* @brief Generate a string that's random, but usually pronounceable. Used to generate initial passwords
*
* @param int $len length
*
* @return string
*/
public static function getRandomName($len)
{
if ($len <= 0) {
return '';
}
$vowels = ['a', 'a', 'ai', 'au', 'e', 'e', 'e', 'ee', 'ea', 'i', 'ie', 'o', 'ou', 'u'];
if (mt_rand(0, 5) == 4) {
$vowels[] = 'y';
}
$cons = [
'b', 'bl', 'br',
'c', 'ch', 'cl', 'cr',
'd', 'dr',
'f', 'fl', 'fr',
'g', 'gh', 'gl', 'gr',
'h',
'j',
'k', 'kh', 'kl', 'kr',
'l',
'm',
'n',
'p', 'ph', 'pl', 'pr',
'qu',
'r', 'rh',
's' ,'sc', 'sh', 'sm', 'sp', 'st',
't', 'th', 'tr',
'v',
'w', 'wh',
'x',
'z', 'zh'
];
$midcons = ['ck', 'ct', 'gn', 'ld', 'lf', 'lm', 'lt', 'mb', 'mm', 'mn', 'mp',
'nd', 'ng', 'nk', 'nt', 'rn', 'rp', 'rt'];
$noend = ['bl', 'br', 'cl', 'cr', 'dr', 'fl', 'fr', 'gl', 'gr',
'kh', 'kl', 'kr', 'mn', 'pl', 'pr', 'rh', 'tr', 'qu', 'wh', 'q'];
$start = mt_rand(0, 2);
if ($start == 0) {
$table = $vowels;
} else {
$table = $cons;
}
$word = '';
for ($x = 0; $x < $len; $x ++) {
$r = mt_rand(0, count($table) - 1);
$word .= $table[$r];
if ($table == $vowels) {
$table = array_merge($cons, $midcons);
} else {
$table = $vowels;
}
}
$word = substr($word, 0, $len);
foreach ($noend as $noe) {
$noelen = strlen($noe);
if ((strlen($word) > $noelen) && (substr($word, -$noelen) == $noe)) {
$word = self::getRandomName($len);
break;
}
}
return $word;
}
/**
* @brief translate and format the networkname of a contact
*
* @param string $network Networkname of the contact (e.g. dfrn, rss and so on)
* @param string $url The contact url
*
* @return string Formatted network name
*/
public static function formatNetworkName($network, $url = 0)
{
if ($network != "") {
if ($url != "") {
$network_name = '<a href="'.$url.'">'.ContactSelector::networkToName($network, $url)."</a>";
} else {
$network_name = ContactSelector::networkToName($network);
}
return $network_name;
}
}
/**
* @brief Remove intentation from a text
*
* @param string $text String to be transformed.
* @param string $chr Optional. Indentation tag. Default tab (\t).
* @param int $count Optional. Default null.
*
* @return string Transformed string.
*/
public static function deindent($text, $chr = "[\t ]", $count = NULL)
{
$lines = explode("\n", $text);
if (is_null($count)) {
$m = [];
$k = 0;
while ($k < count($lines) && strlen($lines[$k]) == 0) {
$k++;
}
preg_match("|^" . $chr . "*|", $lines[$k], $m);
$count = strlen($m[0]);
}
for ($k = 0; $k < count($lines); $k++) {
$lines[$k] = preg_replace("|^" . $chr . "{" . $count . "}|", "", $lines[$k]);
}
return implode("\n", $lines);
}
/**
* @brief Get byte size returned in a Data Measurement (KB, MB, GB)
*
* @param int $bytes The number of bytes to be measured
* @param int $precision Optional. Default 2.
*
* @return string Size with measured units.
*/
public static function formatBytes($bytes, $precision = 2)
{
$units = ['B', 'KB', 'MB', 'GB', 'TB'];
$bytes = max($bytes, 0);
$pow = floor(($bytes ? log($bytes) : 0) / log(1024));
$pow = min($pow, count($units) - 1);
$bytes /= pow(1024, $pow);
return round($bytes, $precision) . ' ' . $units[$pow];
}
/**
* @brief Protect percent characters in sprintf calls
*
* @param string $s String to transform.
*
* @return string Transformed string.
*/
public static function protectSprintf($s)
{
return str_replace('%', '%%', $s);
}
/**
* @brief Base64 Encode URL and translate +/ to -_ Optionally strip padding.
*
* @param string $s URL to encode
* @param boolean $strip_padding Optional. Default false
*
* @return string Encoded URL
*/
public static function base64UrlEncode($s, $strip_padding = false)
{
$s = strtr(base64_encode($s), '+/', '-_');
if ($strip_padding) {
$s = str_replace('=', '', $s);
}
return $s;
}
/**
* @brief Decode Base64 Encoded URL and translate -_ to +/
* @param string $s URL to decode
*
* @return string Decoded URL
*/
public static function base64UrlDecode($s)
{
if (is_array($s)) {
Logger::log('base64url_decode: illegal input: ' . print_r(debug_backtrace(), true));
return $s;
}
/*
* // Placeholder for new rev of salmon which strips base64 padding.
* // PHP base64_decode handles the un-padded input without requiring this step
* // Uncomment if you find you need it.
*
* $l = strlen($s);
* if (!strpos($s,'=')) {
* $m = $l % 4;
* if ($m == 2)
* $s .= '==';
* if ($m == 3)
* $s .= '=';
* }
*
*/
return base64_decode(strtr($s, '-_', '+/'));
}
/**
* @brief Pull out all #hashtags and @person tags from $string.
*
* We also get @person@domain.com - which would make
* the regex quite complicated as tags can also
* end a sentence. So we'll run through our results
* and strip the period from any tags which end with one.
* Returns array of tags found, or empty array.
*
* @param string $string Post content
*
* @return array List of tag and person names
*/
public static function getTags($string)
{
$ret = [];
// Convert hashtag links to hashtags
$string = preg_replace('/#\[url\=([^\[\]]*)\](.*?)\[\/url\]/ism', '#$2', $string);
// ignore anything in a code block
$string = preg_replace('/\[code\](.*?)\[\/code\]/sm', '', $string);
// Force line feeds at bbtags
$string = str_replace(['[', ']'], ["\n[", "]\n"], $string);
// ignore anything in a bbtag
$string = preg_replace('/\[(.*?)\]/sm', '', $string);
// Match full names against @tags including the space between first and last
// We will look these up afterward to see if they are full names or not recognisable.
if (preg_match_all('/(@[^ \x0D\x0A,:?]+ [^ \x0D\x0A@,:?]+)([ \x0D\x0A@,:?]|$)/', $string, $matches)) {
foreach ($matches[1] as $match) {
if (strstr($match, ']')) {
// we might be inside a bbcode color tag - leave it alone
continue;
}
if (substr($match, -1, 1) === '.') {
$ret[] = substr($match, 0, -1);
} else {
$ret[] = $match;
}
}
}
// Otherwise pull out single word tags. These can be @nickname, @first_last
// and #hash tags.
if (preg_match_all('/([!#@][^\^ \x0D\x0A,;:?]+)([ \x0D\x0A,;:?]|$)/', $string, $matches)) {
foreach ($matches[1] as $match) {
if (strstr($match, ']')) {
// we might be inside a bbcode color tag - leave it alone
continue;
}
if (substr($match, -1, 1) === '.') {
$match = substr($match,0,-1);
}
// ignore strictly numeric tags like #1
if ((strpos($match, '#') === 0) && ctype_digit(substr($match, 1))) {
continue;
}
// try not to catch url fragments
if (strpos($string, $match) && preg_match('/[a-zA-z0-9\/]/', substr($string, strpos($string, $match) - 1, 1))) {
continue;
}
$ret[] = $match;
}
}
return $ret;
}
/**
* @brief Check for a valid email string
*
* @param string $email_address Email address to be evaluated.
*
* @return boolean Value indicating whether or not the string is a valid email address.
*/
public static function isValidEmail($email_address)
{
return preg_match('/^[_a-zA-Z0-9\-\+]+(\.[_a-zA-Z0-9\-\+]+)*@[a-zA-Z0-9-]+(\.[a-zA-Z0-9-]+)+$/', $email_address);
}
/**
* @brief Normalize url
*
* @param string $url URL to be normalized.
*
* @return string Normalized URL.
*/
public static function normaliseLink($url) // normalise_link()
{
$ret = str_replace(['https:', '//www.'], ['http:', '//'], $url);
return rtrim($ret, '/');
}
/**
* @brief Normalize OpenID identity
*
* @param string $s OpenID Identity
*
* @return string normalized OpenId Identity
*/
function normaliseOpenID($s)
{
return trim(str_replace(['http://', 'https://'], ['', ''], $s), '/');
}
/**
* @brief Compare two URLs to see if they are the same, but ignore
* slight but hopefully insignificant differences such as if one
* is https and the other isn't, or if one is www.something and
* the other isn't - and also ignore case differences.
*
* @param string $a first url
* @param string $b second url
* @return boolean True if the URLs match, otherwise False
*
*/
public static function compareLink($a, $b)
{
return (strcasecmp(self::normaliseLink($a), self::normaliseLink($b)) === 0);
}
}