Posted at 12/29/2009
虽然Codeigniter可以通过
$this->output->set_header();
来设置文件类型，但当使用Cache功能来缓存非text/html类型的文件时，输出时依然是text/html
要让缓存文件也可以输出成css、js等非text/html类型文件，只需添加一个增强类库即可，方法如下：
- 在application/libraries文件夹下，新建一个文件名为MY_Output.php的文件（注意文件名的大小写）文件内容见下文
- 在使用缓存指令
$this->output->cache();之前引用该类库：$this->load->library('MY_Output');$this->output->cache();
<?php if (!defined('BASEPATH')) exit('No direct script access allowed');
/**
* MY_Output
*
* Modified _write_cache and _display_cache to allow for header caching
* works with CodeIgniter 1.7.0
*
* @package CodeIgniter
* @subpackage Libraries
* @category Output
* @author Arjen van Bochoven
* @link http://codeigniter.com/wiki/Cache_headers
*/
class MY_Output extends CI_Output {
// --------------------------------------------------------------------
/**
* Write a Cache File
*
* @access public
* @return void
*/
function _write_cache($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, serialize(array('exp' => $expire, 'headers' => $this->headers, 'output' => $output)));
flock($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);
// Restore the cache array
$cache = unserialize($cache);
// Validate cache file
if ( ! isset($cache['exp'] ) OR ! isset($cache['headers']) OR ! isset($cache['output']))
{
return FALSE;
}
// Has the file expired? If so we'll delete it.
if (time() >= trim($cache['exp']))
{
@unlink($filepath);
log_message('debug', "Cache file has expired. File deleted");
return FALSE;
}
// Restore headers
$this->headers = $cache['headers'];
// Display the cache
$this->_display($cache['output']);
log_message('debug', "Cache file is current. Sending it to browser.");
return TRUE;
}
}