[php] <?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 */ // ------------------------------------------------------------------------ /** * Output Class * * Responsible 負責 for sending final output to browser * 負責把最終的輸出發送到浏覽器 * @package CodeIgniter * @subpackage Libraries * @category Output * @author ExpressionEngine Dev Team * @link http://codeigniter.com/user_guide/libraries/output.html */ class CI_Output { /** * Current output string * 當前輸出的字符串 * * @var string * @access protected */ protected $final_output; /** * Cache expiration time * 緩存終結的時間 * @var int * @access protected */ protected $cache_expiration = 0; /** * List of server headers * 服務器頭列表 * @var array * @access protected */ protected $headers = array(); /** * List of mime types * * @var array * @access protected */ protected $mime_types = array(); /** * Determines wether profiler is enabled * 是否啟用分析器 * @var book * @access protected */ protected $enable_profiler = FALSE; /** * Determines if output compression is enabled * 是否開啟輸出壓縮 * @var bool * @access protected */ protected $_zlib_oc = FALSE; /** * List of profiler sections * 分析器列表 * * @var array * @access protected */ protected $_profiler_sections = array(); /** * Whether or not to parse variables like {elapsed_time} and {memory_usage} * 是否解析變量{elapsed_time} and {memory_usage} * 注意文檔說這裡有錯誤詳見http://codeigniter.org.cn/user_guide/libraries/output.html * 最下方 * @var bool * @access protected */ protected $parse_exec_vars = TRUE; /** * Constructor * */ function __construct() { // 返回配置項zlib.output_compression的值並賦給$this->_zlib_oc // 如果配置項中開啟了輸出壓縮功能則 $this->_zlib_oc 的值為on $this->_zlib_oc = @ini_get('zlib.output_compression'); // Get mime types for later // 獲取mimetype if (defined('ENVIRONMENT') AND file_exists(APPPATH.'config/'.ENVIRONMENT.'/mimes.php')) { include APPPATH.'config/'.ENVIRONMENT.'/mimes.php'; } else { include APPPATH.'config/mimes.php'; } // $mimes 是mimes.php中定義的一個數組 $this->mime_types = $mimes; log_message('debug', "Output Class Initialized"); } // -------------------------------------------------------------------- /** * Get Output * 使用這個方法，你可以得到將要輸出的數據，並把它保存起來 * Returns the current output string * 返回當前輸出的字符串 * @access public * @return string */ function get_output() { return $this->final_output; } // -------------------------------------------------------------------- /** * Set Output * * Sets the output string * 設置輸出的字符串 * @access public * @param string * @return void */ function set_output($output) { $this->final_output = $output; return $this; } // -------------------------------------------------------------------- /** * Append Output * 在最終輸出字符串後，追加數據 * Appends data onto the output string * * @access public * @param string * @return void */ function append_output($output) { if ($this->final_output == '') { $this->final_output = $output; } else { $this->final_output .= $output; } return $this; } // -------------------------------------------------------------------- /** * Set Header * 使用此方法，允許你設置將會被發送到浏覽器的HTTP協議的標頭，作用相當於php的標准函數: header()。 * Lets you set a server header which will be outputted with the final display. * 允許您設置一個服務器頭用於最終的顯示輸出。 * Note: If a file is cached, headers will not be sent. We need to figure 計算 out * how to permit header data to be saved with the cache data... * * @access public * @param string * @param bool * @return void */ function set_header($header, $replace = TRUE) { // If zlib.output_compression is enabled it will compress the output, // but it will not modify the content-length header to compensate 補償 for // the reduction減少 還原, causing the browser to hang waiting for more data. // We'll just skip content-length in those cases. if ($this->_zlib_oc && strncasecmp($header, 'content-length', 14) == 0) { return; } $this->headers[] = array($header, $replace); return $this; } // -------------------------------------------------------------------- /** * Set Content Type Header * 設置Content-Type * @access public * @param string extension of the file we're outputting * @return void */ function set_content_type($mime_type) { if (strpos($mime_type, '/') === FALSE) { $extension = ltrim($mime_type, '.'); // Is this extension supported? if (isset($this->mime_types[$extension])) { $mime_type =& $this->mime_types[$extension]; if (is_array($mime_type)) { $mime_type = current($mime_type); } } } $header = 'Content-Type: '.$mime_type; $this->headers[] = array($header, TRUE); return $this; } // -------------------------------------------------------------------- /** * Set HTTP Status Header * moved to Common procedural functions in 1.7.2 * 允許你手動設置服務器狀態頭(header) * @access public * @param int the status code * @param string * @return void */ function set_status_header($code = 200, $text = '') { set_status_header($code, $text); return $this; } // -------------------------------------------------------------------- /** * Enable/disable Profiler * 允許你開啟或禁用分析器 * @access public * @param bool * @return void */ function enable_profiler($val = TRUE) { $this->enable_profiler = (is_bool($val)) ? $val : TRUE; return $this; } // -------------------------------------------------------------------- /** * Set Profiler Sections * 設置$this->_profiler_sections * Allows override of default / config settings for Profiler section display * 允許你在評測器啟用時，控制(開/關)其特定部分 * * @access public * @param array * @return void */ function set_profiler_sections($sections) { foreach ($sections as $section => $enable) { $this->_profiler_sections[$section] = ($enable !== FALSE) ? TRUE : FALSE; } return $this; } // -------------------------------------------------------------------- /** * Set Cache * 設置緩存以及緩存時間 * @access public * @param integer 其中 $time 是你希望緩存更新的 分鐘 數 * @return void */ function cache($time) { $this->cache_expiration = ( ! is_numeric($time)) ? 0 : $time; return $this; } // -------------------------------------------------------------------- /** * Display Output * 顯示輸出 * All "view" data is automatically put into this variable by the controller class: * * $this->final_output * * This function sends the finalized output data to the browser along * with any server headers and profile data. It also stops the * benchmark timer so the page rendering speed and memory usage can be shown. * * @access public * @param string * @return mixed */ function _display($output = '') { // Note: We use globals because we can't use $CI =& get_instance() // since this function is sometimes called by the caching mechanism, // which happens before the CI super object is available. // 注意：我們使用global 是因為我們不能使用$CI =& get_instance() global $BM, $CFG; // Grab the super object if we can. // //當然如果可以拿到超級控制器，我們先拿過來。 if (class_exists('CI_Controller')) { $CI =& get_instance(); } // -------------------------------------------------------------------- // Set the output data // 設置輸出數據 if ($output == '') { $output =& $this->final_output; } // -------------------------------------------------------------------- // Do we need to write a cache file? Only if the controller does not have its // own _output() method and we are not dealing with a cache file, which we // can determine by the existence of the $CI object above // 如果緩存時間>0 ，$CI 超級對象存在並且超級對象下面存在_output 方法 // 調用_write_cache 方法，寫一個緩存文件 if ($this->cache_expiration > 0 && isset($CI) && ! method_exists($CI, '_output')) { $this->_write_cache($output); } // -------------------------------------------------------------------- // Parse out the elapsed time and memory usage, // then swap the pseudo-variables with the data // 計算代碼執行時間和內存使用時間 $elapsed = $BM->elapsed_time('total_execution_time_start', 'total_execution_time_end'); // 如果$this->parse_exec_vars為true，將輸出中的{elapsed_time}，{memory_usage} // 替換為計算出的時間。 if ($this->parse_exec_vars === TRUE) { $memory = ( ! function_exists('memory_get_usage')) ? '0' : round(memory_get_usage()/1024/1024, 2).'MB'; $output = str_replace('{elapsed_time}', $elapsed, $output); $output = str_replace('{memory_usage}', $memory, $output); } // -------------------------------------------------------------------- // Is compression requested?壓縮傳輸的處理。 if ($CFG->item('compress_output') === TRUE && $this->_zlib_oc == FALSE) { if (extension_loaded('zlib')) { if (isset($_SERVER['HTTP_ACCEPT_ENCODING']) AND strpos($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip') !== FALSE) { ob_start('ob_gzhandler'); } } } // -------------------------------------------------------------------- // Are there any server headers to send? // 有沒有服務器頭發送？ if (count($this->headers) > 0) { foreach ($this->headers as $header) { @header($header[0], $header[1]); } } // -------------------------------------------------------------------- // Does the $CI object exist? // If not we know we are dealing with a cache file so we'll // simply echo out the data and exit. // 如果沒有$CI就證明當前是一個緩存的輸出，我們只簡單的發送數據並退出 if ( ! isset($CI)) { echo $output; log_message('debug', "Final output sent to browser"); log_message('debug', "Total execution time: ".$elapsed); return TRUE; } // -------------------------------------------------------------------- // Do we need to generate profile data? // If so, load the Profile class and run it. // 如果開啟了性能分析我們就調用， // 會生成一些報告到頁面尾部用於輔助我們調試。 if ($this->enable_profiler == TRUE) { $CI->load->library('profiler'); if ( ! emptyempty($this->_profiler_sections)) { $CI->profiler->set_sections($this->_profiler_sections); } // If the output data contains closing </body> and </html> tags // we will remove them and add them back after we insert the profile data // 如果存在</body></html>標簽，我們將刪除，插入我們的性能分析代碼後再添加回去 if (preg_match("|</body>.*?</html>|is", $output)) { $output = preg_replace("|</body>.*?</html>|is", '', $output); $output .= $CI->profiler->run(); $output .= '</body></html>'; } else { $output .= $CI->profiler->run(); } } // -------------------------------------------------------------------- // Does the controller contain a function named _output()? // If so send the output there. Otherwise, echo it. // 如果控制器中有_output 這個方法我們直接調用 // 如果沒有直接發送數據到浏覽器 if (method_exists($CI, '_output')) { $CI->_output($output); } else { echo $output; // Send it to the browser! } log_message('debug', "Final output sent to browser"); log_message('debug', "Total execution time: ".$elapsed); } // -------------------------------------------------------------------- /** * Write a Cache File * 生成一個緩存文件 * @access public * @param string * @return void */ function _write_cache($output) { // 調用超級對象 $CI =& get_instance(); // 找到緩存路徑 $path = $CI->config->item('cache_path'); $cache_path = ($path == '') ? APPPATH.'cache/' : $path; // 如果緩存路徑不是一個文件夾或者不可寫 ，報錯返回。 if ( ! is_dir($cache_path) OR ! is_really_writable($cache_path)) { log_message('error', "Unable to write cache file: ".$cache_path); return; } // 獲取$uri $uri = $CI->config->item('base_url'). $CI->config->item('index_page'). $CI->uri->uri_string(); // 生成緩存文件。 $cache_path .= md5($uri); if ( ! $fp = @fopen($cache_path, FOPEN_WRITE_CREATE_DESTRUCTIVE)) { log_message('error', "Unable to write cache file: ".$cache_path); return; } // 計算緩存文件過期時間。 $expire = time() + ($this->cache_expiration * 60); if (flock($fp, LOCK_EX)) { fwrite($fp, $expire.'TS--->'.$output); flock($fp, LOCK_UN); } else { log_message('error', "Unable to secure a file lock for file at: ".$cache_path); return; } fclose($fp); @chmod($cache_path, FILE_WRITE_MODE); log_message('debug', "Cache file written: ".$cache_path); } // -------------------------------------------------------------------- /** * Update/serve a cached file * 在CodeIgniter.php裡面有調用此方法，此方法是負責緩存的輸出， * 如果在CodeIgniter.php中調用此方法有輸出，則 * 本次請求的運行將直接結束，直接以緩存輸出作為響應。 * * @access public * @param object config class * @param object uri class * @return void */ function _display_cache(&$CFG, &$URI) { // 取得保存緩存的路徑 $cache_path = ($CFG->item('cache_path') == '') ? APPPATH.'cache/' : $CFG->item('cache_path'); // Build the file path. The file name is an MD5 hash of the full URI // 一條准確的路由都會對應一個緩存文件，緩存文件是對應路由字符串的md5密文。 $uri = $CFG->item('base_url'). $CFG->item('index_page'). $URI->uri_string; $filepath = $cache_path.md5($uri); // 如果沒有此緩存文件，獲取緩存內容失敗，則可以返回FALSE。 if ( ! @file_exists($filepath)) { return FALSE; } // 如果有此緩存文件，但是無法讀，獲取緩存內容失敗，同樣返回FALSE。 if ( ! $fp = @fopen($filepath, FOPEN_READ)) { return FALSE; } // 打開到緩存文件，並以$fp作為句柄。下一步先取得共享鎖（讀取）。 flock($fp, LOCK_SH); $cache = ''; if (filesize($filepath) > 0) { $cache = fread($fp, filesize($filepath)); } // 解鎖 flock($fp, LOCK_UN); // 關閉文件連接。 fclose($fp); // 下面這個TS--->字樣，只是因為CI的緩存文件裡面的內容 // 是規定以數字＋TS--->開頭而已。這個數字是代表創建時間。 // 如果不符合此結構，可視為非CI的緩存文件，或者文件已損壞， // 獲取緩存內容失敗，返回FALSE。 // Strip out the embedded timestamp if ( ! preg_match("/(\d+TS--->)/", $cache, $match)) { return FALSE; } // Has the file expired? If so we'll delete it. // 判斷緩存是否過期，如果過期我們將刪除它 if (time() >= trim(str_replace('TS--->', '', $match['1']))) { if (is_really_writable($cache_path)) { @unlink($filepath); log_message('debug', "Cache file has expired. File deleted"); return FALSE; } } // Display the cache $this->_display(str_replace($match['0'], '', $cache)); log_message('debug', "Cache file is current. Sending it to browser."); return TRUE; } } // END Output Class /* End of file Output.php */ /* Location: ./system/core/Output.php */
