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CI framework source code reading---------Output.php_PHP tutorial
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- 2016-07-14 10:09:18938browse
[php]
/**
* 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 for sending final output to browser
* Responsible for sending the final output to the browser
* @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
* Current output string
*
* @var string
* @access protected
*/
protected $final_output;
/**
* Cache expiration time
* Cache expiration time
* @var int
* @access protected
*/
protected $cache_expiration = 0;
/**
* List of server headers
* Server header list
* @var array
* @access protected
*/
protected $headers = array();
/**
* List of mime types
*
* @var array
* @access protected
*/
protected $mime_types = array();
/**
* Determines wether profiler is enabled
* Whether to enable the analyzer
* @var book
* @access protected
*/
protected $enable_profiler = FALSE;
/**
* Determines if output compression is enabled
* Whether to enable output compression
* @var bool
* @access protected
*/
protected $_zlib_oc = FALSE;
/**
* List of profiler sections
* Analyzer list
*
* @var array
* @access protected
*/
protected $_profiler_sections = array();
/**
* Whether or not to parse variables like {elapsed_time} and {memory_usage}
* 是否解析变量{elapsed_time} and {memory_usage}
* 注意文档说这里有错误详见http://codeigniter.org.cn/user_guide/libraries/output.html
* 最下方
* @var bool
* @access protected
*/
protected $parse_exec_vars = TRUE;
/**
* Constructor
*
*/
function __construct()
{
// Return the value of the configuration item zlib.output_compression and assign it to $this->_zlib_oc
// If the output compression function is turned on in the configuration item, the value of $this->_zlib_oc is on
$this->_zlib_oc = @ini_get('zlib.output_compression');
// Get mime types for later
// Get 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 is an array defined in mimes.php
$this->mime_types = $mimes;
log_message('debug', "Output Class Initialized");
}
//------------------------------------------------ -----------------------
/**
* Get Output
* Using this method, you can get the data to be output and save it
* Returns the current output string
* Returns the current output string
* @access public
* @return string
*/
function get_output()
{
return $this->final_output;
}
//------------------------------------------------ -----------------------
/**
* Set Output
*
* Sets the output string
* Set the output string
* @access public
* @param string
* @return void
*/
function set_output($output)
{
$this->final_output = $output;
return $this;
}
//------------------------------------------------ -----------------------
/**
* Append Output
* After the final output string, append data
* Appends data onto the output string
*
* @access public
* @param string
* @return void
*/
function append_output($output)
{
if ($this->final_output == '')
{
$this->final_output = $output;
} }
else
{
$this->final_output .= $output;
}
return $this;
}
// --------------------------------------------------------------------
/**
* Set Header
* Using this method, allows you to set the header of the HTTP protocol that will be sent to the browser, which is equivalent to the standard function of PHP: header().
* Lets you set a server header which will be outputted with the final display.
* Allows you to set a server header for final display output.
* Note: If a file is cached, headers will not be sent. We need to figure out
* how to permit header data to be saved with the cache data...
*
* @access public
* @param string
* @param bool
* @return void
*/
function set_header($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 $this;
}
// --------------------------------------------------------------------
/**
* Enable/disable Profiler
* Allows you to enable or disable the analyzer
* @access public
* @param bool
* @return void
*/
function enable_profiler($val = TRUE)
{
$this->enable_profiler = (is_bool($val)) ? $val : TRUE;
return $this;
}
// --------------------------------------------------------------------
/**
* Set Profiler Sections
* Set $this->_profiler_sections
* Allows override of default / config settings for Profiler section display
* Allows you to control (on/off) specific parts of the reviewer when it is enabled
*
* @access public
* @param array
* @return void
*/
function set_profiler_sections($sections)
{
foreach ($sections as $section => $enable)
{
$this->_profiler_sections[$section] = ($enable !== FALSE) ? TRUE : FALSE;
}
return $this;
}
// --------------------------------------------------------------------
/**
* Set Cache
* Set cache and cache time
* @access public
* @param integer where $time is the number of minutes you want the cache to be updated
* @return void
*/
function cache($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.
// Note: We use global because we cannot use $CI =& get_instance()
global $BM, $CFG;
// Grab the super object if we can.
// //Of course, if we can get the super controller, we’ll get it first.
if (class_exists('CI_Controller'))
{
$CI =& get_instance();
} }
// --------------------------------------------- -----------------------
// Set the output data
// Set output data
if ($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
// If the cache time>0, the $CI super object exists and the _output method exists under the super object
// Call the _write_cache method to write a cache file
if ($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
// Calculate code execution time and memory usage time
$elapsed = $BM->elapsed_time('total_execution_time_start', 'total_execution_time_end');
// If $this->parse_exec_vars is true, {elapsed_time}, {memory_usage} in the output will be output
// Replace with the calculated time.
if ($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, $output);
} }
// --------------------------------------------- -----------------------
// Is compression requested? Processing of compression transmission.
if ($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)
{
$CI->load->library('profiler');
if ( ! emptyempty($this->_profiler_sections))
{
$CI->profiler->set_sections($this->_profiler_sections);
}
// If the output data contains closing