Output.php

最后更新于:2022-04-01 20:46:10

~~~ _zlib_oc // 如果配置项中开启了输出压缩功能则 $this->_zlib_oc 的值为on $this->_zlib_oc = @ini_get('zlib.output_compression'); // Get mime types for later // 获取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中定义的一个数组 $this->mime_types = $mimes; log_message('debug', "Output Class Initialized"); } // -------------------------------------------------------------------- /** * Get Output * 使用这个方法,你可以得到将要输出的数据,并把它保存起来 * Returns the current output string * 返回当前输出的字符串 * @access public * @return string */ function get_output() { return $this->final_output; } // -------------------------------------------------------------------- /** * Set Output * * Sets the output string * 设置输出的字符串 * @access public * @param string * @return void */ function set_output($output) { $this->final_output = $output; return $this; } // -------------------------------------------------------------------- /** * Append Output * 在最终输出字符串后,追加数据 * Appends data onto the output string * * @access public * @param string * @return void */ function append_output($output) { if ($this->final_output == '') { $this->final_output = $output; } else { $this->final_output .= $output; } return $this; } // -------------------------------------------------------------------- /** * Set Header * 使用此方法,允许你设置将会被发送到浏览器的HTTP协议的标头,作用相当于php的标准函数: header()。 * Lets you set a server header which will be outputted with the final display. * 允许您设置一个服务器头用于最终的显示输出。 * Note: If a file is cached, headers will not be sent. We need to figure 计算 out * how to permit header data to be saved with the cache data... * * @access public * @param string * @param bool * @return void */ function set_header($header, $replace = TRUE) { // If zlib.output_compression is enabled it will compress the output, // but it will not modify the content-length header to compensate 补偿 for // the reduction减少 还原, causing the browser to hang waiting for more data. // We'll just skip content-length in those cases. if ($this->_zlib_oc && strncasecmp($header, 'content-length', 14) == 0) { return; } $this->headers[] = array($header, $replace); return $this; } // -------------------------------------------------------------------- /** * Set Content Type Header * 设置Content-Type * @access public * @param string extension of the file we're outputting * @return void */ function set_content_type($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 $this; } // -------------------------------------------------------------------- /** * Set HTTP Status Header * moved to Common procedural functions in 1.7.2 * 允许你手动设置服务器状态头(header) * @access public * @param int the status code * @param string * @return void */ function set_status_header($code = 200, $text = '') { set_status_header($code, $text); return $this; } // -------------------------------------------------------------------- /** * Enable/disable Profiler * 允许你开启或禁用分析器 * @access public * @param bool * @return void */ function enable_profiler($val = TRUE) { $this->enable_profiler = (is_bool($val)) ? $val : TRUE; return $this; } // -------------------------------------------------------------------- /** * Set Profiler Sections * 设置$this->_profiler_sections * Allows override of default / config settings for Profiler section display * 允许你在评测器启用时,控制(开/关)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 * 设置缓存以及缓存时间 * @access public * @param integer 其中 $time 是你希望缓存更新的 分钟 数 * @return void */ function cache($time) { $this->cache_expiration = ( ! is_numeric($time)) ? 0 : $time; return $this; } // -------------------------------------------------------------------- /** * Display Output * 显示输出 * 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 $CI =& get_instance() // since this function is sometimes called by the caching mechanism, // which happens before the CI super object is available. // 注意:我们使用global 是因为我们不能使用$CI =& get_instance() global $BM, $CFG; // Grab the super object if we can. // //当然如果可以拿到超级控制器,我们先拿过来。 if (class_exists('CI_Controller')) { $CI =& get_instance(); } // -------------------------------------------------------------------- // Set the output data // 设置输出数据 if ($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 $CI object above // 如果缓存时间>0 ,$CI 超级对象存在并且超级对象下面存在_output 方法 // 调用_write_cache 方法,写一个缓存文件 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 // 计算代码执行时间和内存使用时间 $elapsed = $BM->elapsed_time('total_execution_time_start', 'total_execution_time_end'); // 如果$this->parse_exec_vars为true,将输出中的{elapsed_time},{memory_usage} // 替换为计算出的时间。 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, $output); } // -------------------------------------------------------------------- // Is compression requested?压缩传输的处理。 if ($CFG->item('compress_output') === TRUE && $this->_zlib_oc == FALSE) { if (extension_loaded('zlib')) { if (isset($_SERVER['HTTP_ACCEPT_ENCODING']) AND strpos($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip') !== FALSE) { ob_start('ob_gzhandler'); } } } // -------------------------------------------------------------------- // Are there any server headers to send? // 有没有服务器头发送? if (count($this->headers) > 0) { foreach ($this->headers as $header) { @header($header[0], $header[1]); } } // -------------------------------------------------------------------- // Does the $CI object exist? // If not we know we are dealing with a cache file so we'll // simply echo out the data and exit. // 如果没有$CI就证明当前是一个缓存的输出,我们只简单的发送数据并退出 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. // 如果开启了性能分析我们就调用, // 会生成一些报告到页面尾部用于辅助我们调试。 if ($this->enable_profiler == TRUE) { $CI->load->library('profiler'); if ( ! empty($this->_profiler_sections)) { $CI->profiler->set_sections($this->_profiler_sections); } // If the output data contains closing and tags // we will remove them and add them back after we insert the profile data // 如果存在标签,我们将删除,插入我们的性能分析代码后再添加回去 if (preg_match("|.*?|is", $output)) { $output = preg_replace("|.*?|is", '', $output); $output .= $CI->profiler->run(); $output .= ''; } else { $output .= $CI->profiler->run(); } } // -------------------------------------------------------------------- // Does the controller contain a function named _output()? // If so send the output there. Otherwise, echo it. // 如果控制器中有_output 这个方法我们直接调用 // 如果没有直接发送数据到浏览器 if (method_exists($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 * 生成一个缓存文件 * @access public * @param string * @return void */ function _write_cache($output) { // 调用超级对象 $CI =& get_instance(); // 找到缓存路径 $path = $CI->config->item('cache_path'); $cache_path = ($path == '') ? APPPATH.'cache/' : $path; // 如果缓存路径不是一个文件夹或者不可写 ,报错返回。 if ( ! is_dir($cache_path) OR ! is_really_writable($cache_path)) { log_message('error', "Unable to write cache file: ".$cache_path); return; } // 获取$uri $uri = $CI->config->item('base_url'). $CI->config->item('index_page'). $CI->uri->uri_string(); // 生成缓存文件。 $cache_path .= md5($uri); if ( ! $fp = @fopen($cache_path, FOPEN_WRITE_CREATE_DESTRUCTIVE)) { log_message('error', "Unable to write cache file: ".$cache_path); return; } // 计算缓存文件过期时间。 $expire = time() + ($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: ".$cache_path); } // -------------------------------------------------------------------- /** * Update/serve a cached file * 在CodeIgniter.php里面有调用此方法,此方法是负责缓存的输出, * 如果在CodeIgniter.php中调用此方法有输出,则 * 本次请求的运行将直接结束,直接以缓存输出作为响应。 * * @access public * @param object config class * @param object uri class * @return void */ function _display_cache(&$CFG, &$URI) { // 取得保存缓存的路径 $cache_path = ($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 // 一条准确的路由都会对应一个缓存文件,缓存文件是对应路由字符串的md5密文。 $uri = $CFG->item('base_url'). $CFG->item('index_page'). $URI->uri_string; $filepath = $cache_path.md5($uri); // 如果没有此缓存文件,获取缓存内容失败,则可以返回FALSE。 if ( ! @file_exists($filepath)) { return FALSE; } // 如果有此缓存文件,但是无法读,获取缓存内容失败,同样返回FALSE。 if ( ! $fp = @fopen($filepath, FOPEN_READ)) { return FALSE; } // 打开到缓存文件,并以$fp作为句柄。下一步先取得共享锁(读取)。 flock($fp, LOCK_SH); $cache = ''; if (filesize($filepath) > 0) { $cache = fread($fp, filesize($filepath)); } // 解锁 flock($fp, LOCK_UN); // 关闭文件连接。 fclose($fp); // 下面这个TS--->字样,只是因为CI的缓存文件里面的内容 // 是规定以数字+TS--->开头而已。这个数字是代表创建时间。 // 如果不符合此结构,可视为非CI的缓存文件,或者文件已损坏, // 获取缓存内容失败,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. // 判断缓存是否过期,如果过期我们将删除它 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 */ ~~~
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