download.php.svn-base

PHP 知识管理系统（基于树结构的知识管理系统）, 英文原版的PHP源码。

<?php
/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */

/**
 * HTTP::Download
 * 
 * PHP versions 4 and 5
 *
 * @category   HTTP
 * @package    HTTP_Download
 * @author     Michael Wallner <[e-mail]>
 * @copyright  2003-2005 Michael Wallner
 * @license    BSD, revised
 * @version    CVS: $Id$
 * @link       http://pear.php.net/package/HTTP_Download
 */

// {{{ includes
/**
 * Requires PEAR
 */
require_once 'PEAR.php';

/**
 * Requires HTTP_Header
 */
require_once 'HTTP/Header.php';
// }}}

// {{{ constants
/**#@+ Use with HTTP_Download::setContentDisposition() **/
/**
 * Send data as attachment
 */
define('HTTP_DOWNLOAD_ATTACHMENT', 'attachment');
/**
 * Send data inline
 */
define('HTTP_DOWNLOAD_INLINE', 'inline');
/**#@-**/

/**#@+ Use with HTTP_Download::sendArchive() **/
/**
 * Send as uncompressed tar archive
 */
define('HTTP_DOWNLOAD_TAR', 'TAR');
/**
 * Send as gzipped tar archive
 */
define('HTTP_DOWNLOAD_TGZ', 'TGZ');
/**
 * Send as bzip2 compressed tar archive
 */
define('HTTP_DOWNLOAD_BZ2', 'BZ2');
/**
 * Send as zip archive
 */
define('HTTP_DOWNLOAD_ZIP', 'ZIP');
/**#@-**/

/**#@+
 * Error constants
 */
define('HTTP_DOWNLOAD_E_HEADERS_SENT',          -1);
define('HTTP_DOWNLOAD_E_NO_EXT_ZLIB',           -2);
define('HTTP_DOWNLOAD_E_NO_EXT_MMAGIC',         -3);
define('HTTP_DOWNLOAD_E_INVALID_FILE',          -4);
define('HTTP_DOWNLOAD_E_INVALID_PARAM',         -5);
define('HTTP_DOWNLOAD_E_INVALID_RESOURCE',      -6);
define('HTTP_DOWNLOAD_E_INVALID_REQUEST',       -7);
define('HTTP_DOWNLOAD_E_INVALID_CONTENT_TYPE',  -8);
define('HTTP_DOWNLOAD_E_INVALID_ARCHIVE_TYPE',  -9);
/**#@-**/
// }}}

/** 
 * Send HTTP Downloads/Responses.
 *
 * With this package you can handle (hidden) downloads.
 * It supports partial downloads, resuming and sending 
 * raw data ie. from database BLOBs.
 * 
 * <i>ATTENTION:</i>
 * You shouldn't use this package together with ob_gzhandler or 
 * zlib.output_compression enabled in your php.ini, especially 
 * if you want to send already gzipped data!
 * 
 * @access   public
 * @version  $Revision$
 */
class HTTP_Download
{
    // {{{ protected member variables
    /**
     * Path to file for download
     *
     * @see     HTTP_Download::setFile()
     * @access  protected
     * @var     string
     */
    var $file = '';
    
    /**
     * Data for download
     *
     * @see     HTTP_Download::setData()
     * @access  protected
     * @var     string
     */
    var $data = null;
    
    /**
     * Resource handle for download
     *
     * @see     HTTP_Download::setResource()
     * @access  protected
     * @var     int
     */
    var $handle = null;
    
    /**
     * Whether to gzip the download
     *
     * @access  protected
     * @var     bool
     */
    var $gzip = false;
    
    /**
     * Whether to allow caching of the download on the clients side
     * 
     * @access  protected
     * @var     bool
     */
    var $cache = true;
    
    /**
     * Size of download
     *
     * @access  protected
     * @var     int
     */
    var $size = 0;
    
    /**
     * Last modified
     *
     * @access  protected
     * @var     int
     */
    var $lastModified = 0;
    
    /**
     * HTTP headers
     *
     * @access  protected
     * @var     array
     */
    var $headers   = array(
        'Content-Type'  => 'application/x-octetstream',
        'Pragma'        => 'cache',
        'Cache-Control' => 'public, must-revalidate, max-age=0',
        'Accept-Ranges' => 'bytes',
        'X-Sent-By'     => 'PEAR::HTTP::Download'
    );
 
    /**
     * HTTP_Header
     * 
     * @access  protected
     * @var     object
     */
    var $HTTP = null;
    
    /**
     * ETag
     * 
     * @access  protected
     * @var     string
     */
    var $etag = '';
    
    /**
     * Buffer Size
     * 
     * @access  protected
     * @var     int
     */
    var $bufferSize = 2097152;
    
    /**
     * Throttle Delay
     * 
     * @access  protected
     * @var     float
     */
    var $throttleDelay = 0;
    
    /**
     * Sent Bytes
     * 
     * @access  public
     * @var     int
     */
    var $sentBytes = 0;
    // }}}
    
    // {{{ constructor
    /**
     * Constructor
     *
     * Set supplied parameters.
     * 
     * @access  public
     * @param   array   $params     associative array of parameters
     * 
     *          <b>one of:</b>
     *                  o 'file'                => path to file for download
     *                  o 'data'                => raw data for download
     *                  o 'resource'            => resource handle for download
     * <br/>
     *          <b>and any of:</b>
     *                  o 'cache'               => whether to allow cs caching
     *                  o 'gzip'                => whether to gzip the download
     *                  o 'lastmodified'        => unix timestamp
     *                  o 'contenttype'         => content type of download
     *                  o 'contentdisposition'  => content disposition
     *                  o 'buffersize'          => amount of bytes to buffer
     *                  o 'throttledelay'       => amount of secs to sleep
     *                  o 'cachecontrol'        => cache privacy and validity
     * 
     * <br />
     * 'Content-Disposition' is not HTTP compliant, but most browsers 
     * follow this header, so it was borrowed from MIME standard.
     * 
     * It looks like this: <br />
     * "Content-Disposition: attachment; filename=example.tgz".
     * 
     * @see HTTP_Download::setContentDisposition()
     */
    function HTTP_Download($params = array())
    {
        $this->HTTP = &new HTTP_Header;
        $this->setParams($params);
    }
    // }}}
    
    // {{{ public methods
    /**
     * Set parameters
     * 
     * Set supplied parameters through its accessor methods.
     *
     * @access  public
     * @return  mixed   Returns true on success or PEAR_Error on failure.
     * @param   array   $params     associative array of parameters
     * 
     * @see     HTTP_Download::HTTP_Download()
     */
    function setParams($params)
    {
        foreach((array) $params as $param => $value){
            $method = 'set'. $param;
            
            if (!method_exists($this, $method)) {
                return PEAR::raiseError(
                    "Method '$method' doesn't exist.",
                    HTTP_DOWNLOAD_E_INVALID_PARAM
                );
            }
            
            $e = call_user_func_array(array(&$this, $method), (array) $value);
            
            if (PEAR::isError($e)) {
                return $e;
            }
        }
        return true;
    }
    
    /**
     * Set path to file for download
     *
     * The Last-Modified header will be set to files filemtime(), actually.
     * Returns PEAR_Error (HTTP_DOWNLOAD_E_INVALID_FILE) if file doesn't exist.
     * Sends HTTP 404 status if $send_404 is set to true.
     * 
     * @access  public
     * @return  mixed   Returns true on success or PEAR_Error on failure.
     * @param   string  $file       path to file for download
     * @param   bool    $send_404   whether to send HTTP/404 if
     *                              the file wasn't found
     */
    function setFile($file, $send_404 = true)
    {
        $file = realpath($file);
        if (!is_file($file)) {
            if ($send_404) {
                $this->HTTP->sendStatusCode(404);
            }
            return PEAR::raiseError(
                "File '$file' not found.",
                HTTP_DOWNLOAD_E_INVALID_FILE
            );
        }
        $this->setLastModified(filemtime($file));
        $this->file = $file;
        $this->size = filesize($file);
        return true;
    }
    
    /**
     * Set data for download
     *
     * Set $data to null if you want to unset this.
     * 
     * @access  public
     * @return  void
     * @param   $data   raw data to send
     */
    function setData($data = null)
    {
        $this->data = $data;
        $this->size = strlen($data);
    }
    
    /**
     * Set resource for download
     *
     * The resource handle supplied will be closed after sending the download.
     * Returns a PEAR_Error (HTTP_DOWNLOAD_E_INVALID_RESOURCE) if $handle 
     * is no valid resource. Set $handle to null if you want to unset this.
     * 
     * @access  public
     * @return  mixed   Returns true on success or PEAR_Error on failure.
     * @param   int     $handle     resource handle
     */
    function setResource($handle = null)
    {
        if (!isset($handle)) {
            $this->handle = null;
            $this->size = 0;
            return true;
        }
        
        if (is_resource($handle)) {
            $this->handle = $handle;
            $filestats    = fstat($handle);
            $this->size   = $filestats['size'];
            return true;
        }

        return PEAR::raiseError(
            "Handle '$handle' is no valid resource.",
            HTTP_DOWNLOAD_E_INVALID_RESOURCE
        );
    }
    
    /**
     * Whether to gzip the download
     *
     * Returns a PEAR_Error (HTTP_DOWNLOAD_E_NO_EXT_ZLIB)
     * if ext/zlib is not available/loadable.
     * 
     * @access  public
     * @return  mixed   Returns true on success or PEAR_Error on failure.
     * @param   bool    $gzip   whether to gzip the download
     */
    function setGzip($gzip = false)
    {
        if ($gzip && !PEAR::loadExtension('zlib')){
            return PEAR::raiseError(
                'GZIP compression (ext/zlib) not available.',
                HTTP_DOWNLOAD_E_NO_EXT_ZLIB
            );
        }
        $this->gzip = (bool) $gzip;
        return true;
    }

    /**
     * Whether to allow caching
     * 
     * If set to true (default) we'll send some headers that are commonly
     * used for caching purposes like ETag, Cache-Control and Last-Modified.
     * 
     * If caching is disabled, we'll send the download no matter if it
     * would actually be cached at the client side.
     *
     * @access  public
     * @return  void
     * @param   bool    $cache  whether to allow caching
     */
    function setCache($cache = true)
    {
        $this->cache = (bool) $cache;
    }
    
    /**
     * Whether to allow proxies to cache
     * 
     * If set to 'private' proxies shouldn't cache the response.
     * This setting defaults to 'public' and affects only cached responses.
     * 
     * @access  public
     * @return  bool
     * @param   string  $cache  private or public
     * @param   int     $maxage maximum age of the client cache entry
     */
    function setCacheControl($cache = 'public', $maxage = 0)
    {
        switch ($cache = strToLower($cache))
        {
            case 'private':
            case 'public':
                $this->headers['Cache-Control'] = 
                    $cache .', must-revalidate, max-age='. abs($maxage);
                return true;
            break;
        }
        return false;
    }
    
    /**
     * Set ETag
     * 
     * Sets a user-defined ETag for cache-validation.  The ETag is usually
     * generated by HTTP_Download through its payload information.
     * 
     * @access  public
     * @return  void
     * @param   string  $etag Entity tag used for strong cache validation.
     */
    function setETag($etag = null)
    {
        $this->etag = (string) $etag;
    }
    
    /**
     * Set Size of Buffer
     * 
     * The amount of bytes specified as buffer size is the maximum amount
     * of data read at once from resources or files.  The default size is 2M
     * (2097152 bytes).  Be aware that if you enable gzip compression and
     * you set a very low buffer size that the actual file size may grow
     * due to added gzip headers for each sent chunk of the specified size.
     * 
     * Returns PEAR_Error (HTTP_DOWNLOAD_E_INVALID_PARAM) if $size is not
     * greater than 0 bytes.
     * 
     * @access  public
     * @return  mixed   Returns true on success or PEAR_Error on failure.
     * @param   int     $bytes Amount of bytes to use as buffer.
     */
    function setBufferSize($bytes = 2097152)
    {
        if (0 >= $bytes) {
            return PEAR::raiseError(
                'Buffer size must be greater than 0 bytes ('. $bytes .' given)',
                HTTP_DOWNLOAD_E_INVALID_PARAM);
        }
        $this->bufferSize = abs($bytes);
        return true;
    }
    
    /**
     * Set Throttle Delay
     * 
     * Set the amount of seconds to sleep after each chunck that has been
     * sent.  One can implement some sort of throttle through adjusting the
     * buffer size and the throttle delay.  With the following settings
     * HTTP_Download will sleep a second after each 25 K of data sent.
     * 
     * <code>
     *  Array(
     *      'throttledelay' => 1,
     *      'buffersize'    => 1024 * 25,
     *  )
     * </code>
     * 
     * Just be aware that if gzipp'ing is enabled, decreasing the chunk size 
     * too much leads to proportionally increased network traffic due to added
     * gzip header and bottom bytes around each chunk.
     * 
     * @access  public
     * @return  void
     * @param   float   $seconds    Amount of seconds to sleep after each 
     *                              chunk that has been sent.
     */
    function setThrottleDelay($seconds = 0)
    {
        $this->throttleDelay = abs($seconds) * 1000;
    }
    
    /**
     * Set "Last-Modified"
     *
     * This is usually determined by filemtime() in HTTP_Download::setFile()
     * If you set raw data for download with HTTP_Download::setData() and you
     * want do send an appropiate "Last-Modified" header, you should call this
     * method.
     * 
     * @access  public
     * @return  void
     * @param   int     unix timestamp
     */
    function setLastModified($last_modified)
    {
        $this->lastModified = $this->headers['Last-Modified'] = (int) $last_modified;
    }
    
    /**
     * Set Content-Disposition header
     * 
     * @see HTTP_Download::HTTP_Download
     *