全局函數文件Common.php · php CI 框架源碼閱讀筆記

文件位置：Location:?./system/core/Common.php CodeIgniter?使用了一些全局定義的函數來完成操作，在任何情況下你都能夠使用這些函數。使用他們不需要載入任何類庫或輔助函數。這些函數主要用于加載基類和執行請求。 1、?第一個函數is_php? 判斷當前php版本是否大于指定的php版本，有些地方需要用到這個函數 2、?判斷文件夾是否有可寫權限is_really_writable() 因為函數is_writable()在window和unix中并不可靠，所以要對它進行重新封裝在Windows平臺，is_writable()函數在實際沒有文件寫權限時也返回真。那是因為，只有文件有只讀屬性時，操作系統才向PHP報告為假。在unix中當safe_mode為開啟狀態下也是不可靠的。這個函數依靠對文件的先行寫入來判斷是否真的具有寫權限。 3、?類注冊器load_class() 這是一個單例模式的函數，如果請求的類沒有找到會將它設置為一個靜態變量，如果以前存在就直接返回。 4、?is_loaded();?追蹤已經加載的類，這個函數被load_class?調用 5、?get_config();?加載主配置文件 6、?config_item()?返回指定的配置項 7、?show_error錯誤處理程序這個函數調用異常處理類并且使用application/errors/error_general.php模板來顯示錯誤 8、?show_404?404頁面處理程序? 這個函數和show_error函數相似使用application/errors/error_404.php模板來顯示的。 9、?log_message(‘級別’,?‘消息’)?記錄錯誤日志這個函數可以讓你將消息寫入記錄文件中。你必須在第一個參數中選擇三個“級別“中的任何一個,?指明它是那一類消息(調試?debug,?錯誤?error,?信息info)。?第二個參數是消息本身。他會調用system/libraries/log.php?進行處理如果這個config_item('log_threshold')?為0?則不進行任何處理，也就不會記錄錯誤日志了 10、set_status_header???設置http狀態頭 11、_exception_handler???異常處理程序 12、remove_invisible_characters??去除看不見的字符??這個函數能防止在ASCII字符之間插入空字符，如Java\0script.? 13、html_escape?把一些預定義的字符轉換為?HTML?實體它接受字符串和數組。有助于防止跨站腳本攻擊（XSS）。文件源碼： ~~~ <?php if ( ! defined('BASEPATH')) exit('No direct script access allowed'); /** * CodeIgniter * * An open source application development framework for PHP 5.1.6 or newer * * @package CodeIgniter * @author ExpressionEngine Dev Team * @copyright Copyright (c) 2008 - 2011, EllisLab, Inc. * @license http://codeigniter.com/user_guide/license.html * @link http://codeigniter.com * @since Version 1.0 * @filesource */ // ------------------------------------------------------------------------ /** * Common Functions * * Loads the base classes and executes 執行 the request. * * @package CodeIgniter * @subpackage codeigniter * @category Common Functions * @author ExpressionEngine Dev Team * @link http://codeigniter.com/user_guide/ */ // ------------------------------------------------------------------------ /** * Determines if the current version of PHP is greater 較大的 then the supplied 提供的 value * * Since there are a few 很少的 places where we conditionally 有條件的 test for PHP > 5 * we'll set a static variable. * * @access public * @param string * @return bool TRUE if the current version is $version or higher */ if ( ! function_exists('is_php')) { function is_php($version = '5.0.0') { static $_is_php; $version = (string)$version; if ( ! isset($_is_php[$version])) { $_is_php[$version] = (version_compare(PHP_VERSION, $version) < 0) ? FALSE : TRUE; } return $_is_php[$version]; } } // ------------------------------------------------------------------------ /** * Tests for file writability 可寫性 * * is_writable() returns TRUE on Windows servers when you really can't write to * the file, based on the read-only attribute. is_writable() is also unreliable 不可靠的 * on Unix servers if safe_mode is on. * * @access private * @return void */ if ( ! function_exists('is_really_writable')) { function is_really_writable($file) { // If we're on a Unix server with safe_mode off we call is_writable if (DIRECTORY_SEPARATOR == '/' AND @ini_get("safe_mode") == FALSE) { return is_writable($file); } // For windows servers and safe_mode "on" installations we'll actually // write a file then read it. Bah... if (is_dir($file)) { $file = rtrim($file, '/').'/'.md5(mt_rand(1,100).mt_rand(1,100)); if (($fp = @fopen($file, FOPEN_WRITE_CREATE)) === FALSE) { return FALSE; } fclose($fp); @chmod($file, DIR_WRITE_MODE); @unlink($file); return TRUE; } elseif ( ! is_file($file) OR ($fp = @fopen($file, FOPEN_WRITE_CREATE)) === FALSE) { return FALSE; } fclose($fp); return TRUE; } } // ------------------------------------------------------------------------ /** * Class registry * * This function acts as 扮演一個 a singleton.單例模式 If the requested class does not * exist it is instantiated and set to a static variable. If it has * previously 以前 been instantiated the variable is returned. * * @access public * @param string the class name being requested * @param string the directory where the class should be found * @param string the class name prefix * @return object */ if ( ! function_exists('load_class')) { function &load_class($class, $directory = 'libraries', $prefix = 'CI_') { static $_classes = array(); // Does the class exist? If so, we're done... if (isset($_classes[$class])) { return $_classes[$class]; } $name = FALSE; // Look for the class first in the local application/libraries folder // then in the native system/libraries folder foreach (array(APPPATH, BASEPATH) as $path) { if (file_exists($path.$directory.'/'.$class.'.php')) { $name = $prefix.$class; if (class_exists($name) === FALSE) { require($path.$directory.'/'.$class.'.php'); } break; } } // Is the request a class extension? If so we load it too if (file_exists(APPPATH.$directory.'/'.config_item('subclass_prefix').$class.'.php')) { $name = config_item('subclass_prefix').$class; if (class_exists($name) === FALSE) { require(APPPATH.$directory.'/'.config_item('subclass_prefix').$class.'.php'); } } // Did we find the class? if ($name === FALSE) { // Note: We use exit() rather then show_error() in order to avoid a // self-referencing loop with the Excptions class exit('Unable to locate the specified class: '.$class.'.php'); } // Keep track of what we just loaded is_loaded($class); $_classes[$class] = new $name(); return $_classes[$class]; } } // -------------------------------------------------------------------- /** * Keeps track 追蹤 of which libraries have been loaded. This function is * called by the load_class() function above * * @access public * @return array */ if ( ! function_exists('is_loaded')) { function &is_loaded($class = '') { static $_is_loaded = array(); if ($class != '') { $_is_loaded[strtolower($class)] = $class; } return $_is_loaded; } } // ------------------------------------------------------------------------ /** * Loads the main config.php file * * This function lets us grab 獲取 the config file even 甚至 if the Config class * hasn't been instantiated yet * * @access private * @return array */ if ( ! function_exists('get_config')) { function &get_config($replace = array()) { static $_config; if (isset($_config)) { return $_config[0]; } // Is the config file in the environment folder? if ( ! defined('ENVIRONMENT') OR ! file_exists($file_path = APPPATH.'config/'.ENVIRONMENT.'/config.php')) { $file_path = APPPATH.'config/config.php'; } // Fetch 取得、拿來 the config file if ( ! file_exists($file_path)) { exit('The configuration file does not exist.'); } require($file_path); // Does the $config array exist in the file? if ( ! isset($config) OR ! is_array($config)) { exit('Your config file does not appear to be formatted correctly.'); } // Are any values being dynamically replaced? if (count($replace) > 0) { foreach ($replace as $key => $val) { if (isset($config[$key])) { $config[$key] = $val; } } } return $_config[0] =& $config; } } // ------------------------------------------------------------------------ /** * Returns the specified 指定的 config item * * @access public * @return mixed */ if ( ! function_exists('config_item')) { function config_item($item) { static $_config_item = array(); if ( ! isset($_config_item[$item])) { $config =& get_config(); if ( ! isset($config[$item])) { return FALSE; } $_config_item[$item] = $config[$item]; } return $_config_item[$item]; } } // ------------------------------------------------------------------------ /** * Error Handler 處理器、處理程序 * * This function lets us invoke 調用 the exception 異常 class and * display errors using the standard 標準 error template located 地處、處于 * in application/errors/errors.php * This function will send the error page directly to the * browser and exit. * * @access public * @return void */ if ( ! function_exists('show_error')) { function show_error($message, $status_code = 500, $heading = 'An Error Was Encountered') { $_error =& load_class('Exceptions', 'core'); echo $_error->show_error($heading, $message, 'error_general', $status_code); exit; } } // ------------------------------------------------------------------------ /** * 404 Page Handler * * This function is similar 相似的類似的 to the show_error() function above在。。。上面 * However 然而、但是, instead 代替、反而、更換 of the standard 標準、規格、標準版 error * template it displays * 404 errors. * * @access public * @return void */ if ( ! function_exists('show_404')) { function show_404($page = '', $log_error = TRUE) { $_error =& load_class('Exceptions', 'core'); $_error->show_404($page, $log_error); exit; } } // ------------------------------------------------------------------------ /** * Error Logging Interface 界面 * * We use this as a simple mechanism 機制、原理 to access 接近、進入、通道 the logging * class and send messages to be logged. * * @access public * @return void */ if ( ! function_exists('log_message')) { function log_message($level = 'error', $message, $php_error = FALSE) { static $_log; if (config_item('log_threshold') == 0) { return; } $_log =& load_class('Log'); $_log->write_log($level, $message, $php_error); } } // ------------------------------------------------------------------------ /** * Set HTTP Status Header * * @access public * @param int the status code * @param string * @return void */ if ( ! function_exists('set_status_header')) { function set_status_header($code = 200, $text = '') { $stati = array( 200 => 'OK', 201 => 'Created', 202 => 'Accepted', 203 => 'Non-Authoritative Information', 204 => 'No Content', 205 => 'Reset Content', 206 => 'Partial Content', 300 => 'Multiple Choices', 301 => 'Moved Permanently', 302 => 'Found', 304 => 'Not Modified', 305 => 'Use Proxy', 307 => 'Temporary Redirect', 400 => 'Bad Request', 401 => 'Unauthorized', 403 => 'Forbidden', 404 => 'Not Found', 405 => 'Method Not Allowed', 406 => 'Not Acceptable', 407 => 'Proxy Authentication Required', 408 => 'Request Timeout', 409 => 'Conflict', 410 => 'Gone', 411 => 'Length Required', 412 => 'Precondition Failed', 413 => 'Request Entity Too Large', 414 => 'Request-URI Too Long', 415 => 'Unsupported Media Type', 416 => 'Requested Range Not Satisfiable', 417 => 'Expectation Failed', 500 => 'Internal Server Error', 501 => 'Not Implemented', 502 => 'Bad Gateway', 503 => 'Service Unavailable', 504 => 'Gateway Timeout', 505 => 'HTTP Version Not Supported' ); if ($code == '' OR ! is_numeric($code)) { show_error('Status codes must be numeric', 500); } if (isset($stati[$code]) AND $text == '') { $text = $stati[$code]; } if ($text == '') { show_error('No status text available. Please check your status code number or supply your own message text.', 500); } $server_protocol = (isset($_SERVER['SERVER_PROTOCOL'])) ? $_SERVER['SERVER_PROTOCOL'] : FALSE; if (substr(php_sapi_name(), 0, 3) == 'cgi') { header("Status: {$code} {$text}", TRUE); } elseif ($server_protocol == 'HTTP/1.1' OR $server_protocol == 'HTTP/1.0') { header($server_protocol." {$code} {$text}", TRUE, $code); } else { header("HTTP/1.1 {$code} {$text}", TRUE, $code); } } } // -------------------------------------------------------------------- /** * Exception Handler * * This is the custom 自定義的 exception handler that is declaired at the top * of Codeigniter.php. The main reason 原因、理由 we use this is to permit 許可 * PHP errors to be logged in our own log files since the user may * not have access 接近、進入 to server logs. Since this function * effectively 有效地 intercepts 攔截 PHP errors, however,但是 we also need * to display errors based on the current error_reporting level. * We do that with the use of a PHP error template. * * @access private * @return void */ if ( ! function_exists('_exception_handler')) { function _exception_handler($severity, $message, $filepath, $line) { // We don't bother 打擾、麻煩 with "strict" 嚴格地 notices since they tend 傾向于 to fill up // the log file with excess information that isn't normally very helpful. // For example, if you are running PHP 5 and you use version 4 style // class functions (without prefixes like "public", "private", etc.) // you'll get notices telling you that these have been deprecated. if ($severity == E_STRICT) { return; } $_error =& load_class('Exceptions', 'core'); // Should we display the error? We'll get the current error_reporting // level and add its bits with the severity bits to find out. if (($severity & error_reporting()) == $severity) { $_error->show_php_error($severity, $message, $filepath, $line); } // Should we log the error? No? We're done... if (config_item('log_threshold') == 0) { return; } $_error->log_exception($severity, $message, $filepath, $line); } } // -------------------------------------------------------------------- /** * Remove Invisible 無形的，看不見的 Characters * * This prevents sandwiching 夾層 null characters * between ascii characters, like Java\script. * * @access public * @param string * @return string */ if ( ! function_exists('remove_invisible_characters')) { function remove_invisible_characters($str, $url_encoded = TRUE) { $non_displayables = array(); // every control character except newline (dec 10) // carriage return (dec 13), and horizontal tab (dec 09) if ($url_encoded) { $non_displayables[] = '/%0[0-8bcef]/'; // url encoded 00-08, 11, 12, 14, 15 $non_displayables[] = '/%1[0-9a-f]/'; // url encoded 16-31 } $non_displayables[] = '/[\x00-\x08\x0B\x0C\x0E-\x1F\x7F]+/S'; // 00-08, 11, 12, 14-31, 127 do { $str = preg_replace($non_displayables, '', $str, -1, $count); } while ($count); return $str; } } // ------------------------------------------------------------------------ /** * Returns HTML escaped variable * * @access public * @param mixed * @return mixed */ if ( ! function_exists('html_escape')) { function html_escape($var) { if (is_array($var)) { return array_map('html_escape', $var); } else { return htmlspecialchars($var, ENT_QUOTES, config_item('charset')); } } } /* End of file Common.php */ /* Location: ./system/core/Common.php */ ~~~