<?php
/**
* Shaarli utilities
*/
/**
* Logs a message to a text file
*
* The log format is compatible with fail2ban.
*
* @param string $logFile where to write the logs
* @param string $clientIp the client's remote IPv4/IPv6 address
* @param string $message the message to log
*/
function logm($logFile, $clientIp, $message)
{
file_put_contents(
$logFile,
date('Y/m/d H:i:s').' - '.$clientIp.' - '.strval($message).PHP_EOL,
FILE_APPEND
);
}
/**
* Returns the small hash of a string, using RFC 4648 base64url format
*
* Small hashes:
* - are unique (well, as unique as crc32, at last)
* - are always 6 characters long.
* - only use the following characters: a-z A-Z 0-9 - _ @
* - are NOT cryptographically secure (they CAN be forged)
*
* In Shaarli, they are used as a tinyurl-like link to individual entries,
* built once with the combination of the date and item ID.
* e.g. smallHash('20111006_131924' . 142) --> eaWxtQ
*
* @warning before v0.8.1, smallhashes were built only with the date,
* and their value has been preserved.
*
* @param string $text Create a hash from this text.
*
* @return string generated small hash.
*/
function smallHash($text)
{
$t = rtrim(base64_encode(hash('crc32', $text, true)), '=');
return strtr($t, '+/', '-_');
}
/**
* Tells if a string start with a substring
*
* @param string $haystack Given string.
* @param string $needle String to search at the beginning of $haystack.
* @param bool $case Case sensitive.
*
* @return bool True if $haystack starts with $needle.
*/
function startsWith($haystack, $needle, $case = true)
{
if ($case) {
return (strcmp(substr($haystack, 0, strlen($needle)), $needle) === 0);
}
return (strcasecmp(substr($haystack, 0, strlen($needle)), $needle) === 0);
}
/**
* Tells if a string ends with a substring
*
* @param string $haystack Given string.
* @param string $needle String to search at the end of $haystack.
* @param bool $case Case sensitive.
*
* @return bool True if $haystack ends with $needle.
*/
function endsWith($haystack, $needle, $case = true)
{
if ($case) {
return (strcmp(substr($haystack, strlen($haystack) - strlen($needle)), $needle) === 0);
}
return (strcasecmp(substr($haystack, strlen($haystack) - strlen($needle)), $needle) === 0);
}
/**
* Htmlspecialchars wrapper
* Support multidimensional array of strings.
*
* @param mixed $input Data to escape: a single string or an array of strings.
*
* @return string escaped.
*/
function escape($input)
{
if (is_array($input)) {
$out = array();
foreach($input as $key => $value) {
$out[$key] = escape($value);
}
return $out;
}
return htmlspecialchars($input, ENT_COMPAT, 'UTF-8', false);
}
/**
* Reverse the escape function.
*
* @param string $str the string to unescape.
*
* @return string unescaped string.
*/
function unescape($str)
{
return htmlspecialchars_decode($str);
}
/**
* Sanitize link before rendering.
*
* @param array $link Link to escape.
*/
function sanitizeLink(&$link)
{
$link['url'] = escape($link['url']); // useful?
$link['title'] = escape($link['title']);
$link['description'] = escape($link['description']);
$link['tags'] = escape($link['tags']);
}
/**
* Checks if a string represents a valid date
* @param string $format The expected DateTime format of the string
* @param string $string A string-formatted date
*
* @return bool whether the string is a valid date
*
* @see http://php.net/manual/en/class.datetime.php
* @see http://php.net/manual/en/datetime.createfromformat.php
*/
function checkDateFormat($format, $string)
{
$date = DateTime::createFromFormat($format, $string);
return $date && $date->format($string) == $string;
}
/**
* Generate a header location from HTTP_REFERER.
* Make sure the referer is Shaarli itself and prevent redirection loop.
*
* @param string $referer - HTTP_REFERER.
* @param string $host - Server HOST.
* @param array $loopTerms - Contains list of term to prevent redirection loop.
*
* @return string $referer - final referer.
*/
function generateLocation($referer, $host, $loopTerms = array())
{
$finalReferer = '?';
// No referer if it contains any value in $loopCriteria.
foreach ($loopTerms as $value) {
if (strpos($referer, $value) !== false) {
return $finalReferer;
}
}
// Remove port from HTTP_HOST
if ($pos = strpos($host, ':')) {
$host = substr($host, 0, $pos);
}
$refererHost = parse_url($referer, PHP_URL_HOST);
if (!empty($referer) && (strpos($refererHost, $host) !== false || startsWith('?', $refererHost))) {
$finalReferer = $referer;
}
return $finalReferer;
}
/**
* Validate session ID to prevent Full Path Disclosure.
*
* See #298.
* The session ID's format depends on the hash algorithm set in PHP settings
*
* @param string $sessionId Session ID
*
* @return true if valid, false otherwise.
*
* @see http://php.net/manual/en/function.hash-algos.php
* @see http://php.net/manual/en/session.configuration.php
*/
function is_session_id_valid($sessionId)
{
if (empty($sessionId)) {
return false;
}
if (!$sessionId) {
return false;
}
if (!preg_match('/^[a-zA-Z0-9,-]{2,128}$/', $sessionId)) {
return false;
}
return true;
}
/**
* Sniff browser language to set the locale automatically.
* Note that is may not work on your server if the corresponding locale is not installed.
*
* @param string $headerLocale Locale send in HTTP headers (e.g. "fr,fr-fr;q=0.8,en;q=0.5,en-us;q=0.3").
**/
function autoLocale($headerLocale)
{
// Default if browser does not send HTTP_ACCEPT_LANGUAGE
$attempts = array('en_US');
if (isset($headerLocale)) {
// (It's a bit crude, but it works very well. Preferred language is always presented first.)
if (preg_match('/([a-z]{2})-?([a-z]{2})?/i', $headerLocale, $matches)) {
$loc = $matches[1] . (!empty($matches[2]) ? '_' . strtoupper($matches[2]) : '');
$attempts = array(
$loc.'.UTF-8', $loc, str_replace('_', '-', $loc).'.UTF-8', str_replace('_', '-', $loc),
$loc . '_' . strtoupper($loc).'.UTF-8', $loc . '_' . strtoupper($loc),
$loc . '_' . $loc.'.UTF-8', $loc . '_' . $loc, $loc . '-' . strtoupper($loc).'.UTF-8',
$loc . '-' . strtoupper($loc), $loc . '-' . $loc.'.UTF-8', $loc . '-' . $loc
);
}
}
setlocale(LC_ALL, $attempts);
}
/**
* Generates a default API secret.
*
* Note that the random-ish methods used in this function are predictable,
* which makes them NOT suitable for crypto.
* BUT the random string is salted with the salt and hashed with the username.
* It makes the generated API secret secured enough for Shaarli.
*
* PHP 7 provides random_int(), designed for cryptography.
* More info: http://stackoverflow.com/questions/4356289/php-random-string-generator
* @param string $username Shaarli login username
* @param string $salt Shaarli password hash salt
*
* @return string|bool Generated API secret, 12 char length.
* Or false if invalid parameters are provided (which will make the API unusable).
*/
function generate_api_secret($username, $salt)
{
if (empty($username) || empty($salt)) {
return false;
}
return str_shuffle(substr(hash_hmac('sha512', uniqid($salt), $username), 10, 12));
}
