Output.php

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<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package             CodeIgniter
 * @author              ExpressionEngine Dev Team
 * @copyright   Copyright (c) 2008, 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
 *
 * @package             CodeIgniter
 * @subpackage  Libraries
 * @category    Output
 * @author              ExpressionEngine Dev Team
 * @link                http://codeigniter.com/user_guide/libraries/output.html
 */
class CI_Output {

        var $final_output;
        var $cache_expiration   = 0;
        var $headers                    = array();
        var $enable_profiler    = FALSE;


        function CI_Output()
        {
                log_message('debug', "Output Class Initialized");
        }
        
        // --------------------------------------------------------------------
        
        /**
         * Get Output
         *
         * Returns the current output string
         *
         * @access      public
         * @return      string
         */     
        function get_output()
        {
                return $this->final_output;
        }
        
        // --------------------------------------------------------------------
        
        /**
         * Set Output
         *
         * Sets the output string
         *
         * @access      public
         * @param       string
         * @return      void
         */     
        function set_output($output)
        {
                $this->final_output = $output;
        }

        // --------------------------------------------------------------------

        /**
         * Append Output
         *
         * 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;
                }
        }

        // --------------------------------------------------------------------

        /**
         * Set Header
         *
         * Lets you set a server header which will be outputted with the final display.
         *
         * 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
         * @return      void
         */     
        function set_header($header, $replace = TRUE)
        {
                $this->headers[] = array($header, $replace);
        }

        // --------------------------------------------------------------------
        
        /**
         * Set HTTP Status Header
         *
         * @access      public
         * @param       int     the status code
         * @param       string  
         * @return      void
         */     
        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');
                }

                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.');
                }
                
                $server_protocol = (isset($_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);
                }
        }
        
        // --------------------------------------------------------------------
        
        /**
         * Enable/disable Profiler
         *
         * @access      public
         * @param       bool
         * @return      void
         */     
        function enable_profiler($val = TRUE)
        {
                $this->enable_profiler = (is_bool($val)) ? $val : TRUE;
        }
        
        // --------------------------------------------------------------------
        
        /**
         * Set Cache
         *
         * @access      public
         * @param       integer
         * @return      void
         */     
        function cache($time)
        {
                $this->cache_expiration = ( ! is_numeric($time)) ? 0 : $time;
        }
        
        // --------------------------------------------------------------------
        
        /**
         * Display Output
         *
         * All "view" data is automatically put into this variable by the controller class:
         *
         * $this->final_output
         *
         * This function sends the finalized output data to the browser along
         * with any server headers and profile data.  It also stops the
         * benchmark timer so the page rendering speed and memory usage can be shown.
         *
         * @access      public
         * @return      mixed
         */             
        function _display($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.
                global $BM, $CFG;
                
                // --------------------------------------------------------------------
                
                // Set the output data
                if ($output == '')
                {
                        $output =& $this->final_output;
                }
                
                // --------------------------------------------------------------------
                
                // Do we need to write a cache file?
                if ($this->cache_expiration > 0)
                {
                        $this->_write_cache($output);
                }
                
                // --------------------------------------------------------------------

                // Parse out the elapsed time and memory usage,
                // then swap the pseudo-variables with the data

                $elapsed = $BM->elapsed_time('total_execution_time_start', 'total_execution_time_end');         
                $output = str_replace('{elapsed_time}', $elapsed, $output);
                
                $memory  = ( ! function_exists('memory_get_usage')) ? '0' : round(memory_get_usage()/1024/1024, 2).'MB';
                $output = str_replace('{memory_usage}', $memory, $output);              

                // --------------------------------------------------------------------
                
                // Is compression requested?
                if ($CFG->item('compress_output') === TRUE)
                {
                        if (extension_loaded('zlib'))
                        {
                                if (isset($_SERVER['HTTP_ACCEPT_ENCODING']) AND strpos($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip') !== FALSE)
                                {
                                        ob_start('ob_gzhandler');
                                }
                        }
                }

                // --------------------------------------------------------------------
                
                // Are there any server headers to send?
                if (count($this->headers) > 0)
                {
                        foreach ($this->headers as $header)
                        {
                                @header($header[0], $header[1]);
                        }
                }               

                // --------------------------------------------------------------------
                
                // Does the get_instance() function exist?
                // If not we know we are dealing with a cache file so we'll
                // simply echo out the data and exit.
                if ( ! function_exists('get_instance'))
                {
                        echo $output;
                        log_message('debug', "Final output sent to browser");
                        log_message('debug', "Total execution time: ".$elapsed);
                        return TRUE;
                }
        
                // --------------------------------------------------------------------

                // Grab the super object.  We'll need it in a moment...
                $CI =& get_instance();
                
                // Do we need to generate profile data?
                // If so, load the Profile class and run it.
                if ($this->enable_profiler == TRUE)
                {
                        $CI->load->library('profiler');                         
                                                                                
                        // If the output data contains closing </body> and </html> tags
                        // we will remove them and add them back after we insert the profile data
                        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.
                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
         *
         * @access      public
         * @return      void
         */     
        function _write_cache($output)
        {
                $CI =& get_instance();  
                $path = $CI->config->item('cache_path');
        
                $cache_path = ($path == '') ? BASEPATH.'cache/' : $path;
                
                if ( ! is_dir($cache_path) OR ! is_really_writable($cache_path))
                {
                        return;
                }
                
                $uri =  $CI->config->item('base_url').
                                $CI->config->item('index_page').
                                $CI->uri->uri_string();
                
                $cache_path .= md5($uri);

                if ( ! $fp = @fopen($cache_path, FOPEN_WRITE_CREATE_DESTRUCTIVE))
                {
                        log_message('error', "Unable to write cache file: ".$cache_path);
                        return;
                }
                
                $expire = time() + ($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, DIR_WRITE_MODE);

                log_message('debug', "Cache file written: ".$cache_path);
        }

        // --------------------------------------------------------------------
        
        /**
         * Update/serve a cached file
         *
         * @access      public
         * @return      void
         */     
        function _display_cache(&$CFG, &$URI)
        {
                $cache_path = ($CFG->item('cache_path') == '') ? BASEPATH.'cache/' : $CFG->item('cache_path');
                        
                if ( ! is_dir($cache_path) OR ! is_really_writable($cache_path))
                {
                        return FALSE;
                }
                
                // Build the file path.  The file name is an MD5 hash of the full URI
                $uri =  $CFG->item('base_url').
                                $CFG->item('index_page').
                                $URI->uri_string;
                                
                $filepath = $cache_path.md5($uri);
                
                if ( ! @file_exists($filepath))
                {
                        return FALSE;
                }
        
                if ( ! $fp = @fopen($filepath, FOPEN_READ))
                {
                        return FALSE;
                }
                        
                flock($fp, LOCK_SH);
                
                $cache = '';
                if (filesize($filepath) > 0)
                {
                        $cache = fread($fp, filesize($filepath));
                }
        
                flock($fp, LOCK_UN);
                fclose($fp);
                                        
                // Strip out the embedded timestamp             
                if ( ! preg_match("/(\d+TS--->)/", $cache, $match))
                {
                        return FALSE;
                }
                
                // Has the file expired? If so we'll delete it.
                if (time() >= trim(str_replace('TS--->', '', $match['1'])))
                {               
                        @unlink($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/libraries/Output.php */