<?php
/**
 * HTTP response class
 *
 *
 * $Id$
 *
 * @author gERD Schaufelberger <gerd@php-tools.net>
 * @license PHP License
 * @package WB
 * @subpackage base
 */

WBClass::load( 'WBResponse' );

/**
 * HTTP response class
 *
 * Improved output header
 *
 * @version 0.4.0
 * @package WB
 * @subpackage base
 */
class WBResponse_Http extends WBResponse
{
   /**
    * request path
    * @var string
    */
    protected $_path   = '/';

   /**
    * start
    *
    */
    public function __construct()
    {
        $this->_header['Content-Type']  =   'text/html; charset=utf-8;';
    }

   /**
    * thing send
    *
    * @param WBRequest $request
    * @return bool true un success
    */
    protected function onSend( WBRequest $request )
    {
        $this->_path =  $request->path;

        // caching header
        $cacheControl   =   WBResponse::CACHECONTROL_MUSTREVALIDATE;
        $pragma         =   'no-cache';

        if( $this->_useCache ) {
            $pragma         =   'cache';
            // check browser cache
            if( $request->getMeta('HTTP_IF_NONE_MATCH') === $this->_checksum) {
                $this->setStatus(304);
                return true;
            }

            // add vary header
            $this->addHeader('Vary', 'User-Agent, Accept, Accept-Encoding, Accept-Language, Cookie');

            if ($this->expireAge) {
                $cacheControl   =   'max-age: '.strval($this->expireAge).', ' . $this->cacheControl;
                $this->addHeader('Expires', gmdate('D, j M Y H:i:s', time() + $this->expireAge) . ' GMT');
            }
            $this->addHeader('ETag', $this->_checksum);
        }

        $this->addHeader('Cache-Control', $cacheControl);
        $this->addHeader('Pragma', $pragma);
        $this->addHeader('Content-MD5', $this->_checksum);

        // check content type to activate string replace
        $cType  =   explode(';', $this->_header['Content-Type'], 2);
        $cType  =   array_shift($cType);
        $cType  =   explode('/', $cType);
        if ($cType[0] == 'text' || $cType[1] == 'x-javascript') {
            $this->addOutputFilter( array( $this, 'filterStringReplace' ) );
        }

        /*
         * generic compression filters are not suitable for mixed streaming content
         * @todo reconsider whether compression works anyway
         */
        $zip    =   true;
        $last   =   $this->_data[0]['type'];
        foreach ($this->_data as $d) {
            if ($d['type'] != $last) {
                $zip    =   true;
                break;
            }
        }
        if ($zip) {
            $this->checkCompression( $request );
        }

        return true;
    }

   /**
    * send header
    *
    * @return bool true on success
    */
    protected function sendHeader()
    {
        $this->addHeader( 'HTTP/1.1', $this->_responseStatus . ' ' . $this->_statusCodes[$this->_responseStatus]['msg'] );
        foreach( $this->_header as $name => $value ) {
            if( $value === null ) {
               header( $name );
            }
            else {
               header( $name.': '.$value );
            }
        }

        return true;
    }

   /**
    * Allow output compression
    *
    * Check whether out compression may be used and add output filter: gzip or deflate
    *
    * @return bool true on success
    */
    protected function checkCompression( $request )
    {
        // check config
        if (!WBParam::get('wb/response/compress', 1)) {
            return true;
        }

        // check if deflate is accepted from client
        $acceptEncoding     =   explode(',', trim($request->getMeta( 'HTTP_ACCEPT_ENCODING')));
        $this->_compressor  =   null;

        // get accepted client encodings
        if (in_array('gzip', $acceptEncoding)) {
            $this->addOutputFilter(array($this, 'filterCompress'));
            $this->_compressor   =   'gzip';
            return true;
        }

        if (in_array('deflate', $acceptEncoding)) {
            $this->addOutputFilter(array($this, 'filterCompress'));
            $this->_compressor   =   'deflate';
            return true;
        }

        return true;
    }

   /**
    * Global string replace
    *
    *
    * @param string $in
    * @return string $out
    */
    public function filterStringReplace($in)
    {
        WBClass::load('WBString');
        return WBString::replaceSuperPlaceholders($in, $this->_path);
    }

   /**
    * Applay output filter: compress
    *
    * Either gzip or deflate
    *
    * @param string $in
    * @return string $out
    */
    public function filterCompress($in)
    {
        if (!$this->_compressor) {
            // this should never happen
            return $in;
        }

        // compression does not make sense for little data
        if (strlen($in) < 500) {
            return $in;
        }

        // compress
        switch ($this->_compressor) {
            case 'gzip':
                $this->addHeader('Content-Encoding', 'gzip');
                return gzencode($in);
                break;

            case 'deflate':
                $this->addHeader('Content-Encoding', 'deflate');
                return gzdeflate($in);
                break;

            default:
                break;
        }

        return $in;
    }
}
?>