My take on premium video pay per view (with flashvideo). Solved!

As I have had too many problems trying to solve this, I want to post my solution for two reasons: first, help other people do the same; second, hearing oppinions and enhancements to my solution.

Problem: Some web content can only be accessed paying. Concretely, my paid content are movies, flv format.

Modules involved:

1. flashvideo
2. private_upload
3. a custom module that drupal forced me to create

Context: Drupal has two filesystem settings: public and private. The names are totally wrong, because they should be called unmanaged and managed. Public file system is not managed by drupal, it is apache that serves files directly. Private file system is served by drupal and is considerably slower. If some protection has to be performed on files, then the drupal way is private file system, but with an efficiency cost. One solutions comes with the private_upload module, that implements a mixed public/private file system. Having a public file system, private_upload creates a protected directory. This way, the public file system will be served by apache (considerably faster) and the private part will be served by drupal (slower but only for a part of the contents that need some access control). In my case, the protected content are flv videos served by the flashvideo module.

Solution: Once done, it is not that difficult. What made it difficult was the lack on documentation in the drupal community regarding these aspects. Having properly installed flashvideo and private_upload modules, the first thing is is to theme flashvideo player and put it into template.php:

function mytheme_flashvideo_play_flash($video) {

   // Here begins the modification: we want an address starting with system/files so drupal takes control when the file is private, otherwise don't do anything
   // Get the FlashVars for this video.
   // we ask whether the url is private
   if (_private_upload_is_url_private($video['file'])) {
     //in this case, we add the system part
     $video['file']=_private_upload_replace_start_with($video['file'], 'http://mydomain/web/'._private_upload_path(), 'http://mydomain/web/system/'._private_upload_path()' );
   }
   //end of modification
   $flashvars = flashvideo_get_flashvars($video);

   // Creates an absolute path for the player.
   $loader_path = check_url(file_create_url(flashvideo_variable_get($video['nodetype'], 'player', 'Player.swf')));

   // Get the window mode
   $wmode = '';
   $wmode_param = '';
   switch(flashvideo_variable_get($video['nodetype'], 'mode', 'window')) {
     case 'transparent':
       $wmode = ' wmode="transparent"';
       $wmode_param = '<param name="wmode" value="transparent" />';
       break;
     case 'window':
       $wmode = ' wmode="window" allowfullscreen="true"';
       $wmode_param = '<param name="wmode" value="window" /><param name="allowfullscreen" value="true" />';
       break;
   }

   $output .= '<object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" width="'.$video['width'].'" height="'.$video['height'].'" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab">';
//   if ($flashvars[])
   $output .= '<param name="movie" value="'. $loader_path .'" />'. $wmode_param .'<param name="FlashVars" value="'.$flashvars.'" /><param name="quality" value="high" />';
   $output .= '<embed allowScriptAccess="always" src="'. $loader_path .'" width="'.$video['width'].'" height="'.$video['height'].'" border="0" type="application/x-shockwave-flash" pluginspage="http://www.macromedia.com/go/getflashplayer"';
   $output .= $wmode . ' quality="high" flashvars="'.$flashvars.'" /></object>';
   $output .= (flashvideo_variable_get($video['nodetype'], 'embed', 0) == 1) ? '<br/>' . theme('flashvideo_embed', $output,
$video['nodetype']) : '';
   $output = theme( 'flashvideo_format_play', $video, $output, t('http://www.macromedia.com/go/getflashplayer'),
                                       t('Link to Macromedia Flash Player Download Page'),
                                       t('Download latest Flash Player'));
   return $output;
}

Having made sure drupal will take care of private files, all that is left is to establish some control over private files. First, when flashvideo processes videos, those private ones must be marked private. Then, the only way to control downloads is through hook_file_download. Information is too scarce on this, I hade to try many options until I noticed that hooks can only be controled from modules. A module must be created and activated so paid content is properly controlled. It is a very simple thing, such a small module that even I was able to do it. The module is called paiddownloads, and paiddownloads.module looks like this:

<?php
// $Id$

//This is a copy of the upload_file_download function in upload module with an added control
function paiddownloads_file_download($file) {
  $file = file_create_path($file);
  $result = db_query("SELECT f.* FROM {files} f WHERE filepath = '%s'", $file);
  if ($file = db_fetch_object($result)) {
    if (user_access('view uploaded files')) {
      $node = node_load($file->nid);
      if (node_access('view', $node)) {
        //this is the modification: an added control of a session variable indicating the user has paid for a video
        //this session variable must be set some other place. In my case, as I am using a pay platform, the platform sends info about the commited payment
        if ($node->type == "video" && $SESSION['video'][$file->nid] == 1 ) {
          // if a payment is only for one access, the session variable can be unset here
          $type = mime_header_encode($file->filemime);
          return array(
            'Content-Type: '. $type,
            'Content-Length: '. $file->filesize,
          );
        }
        else {
          return -1;
        }
        //end of modification
      }
      else {
        return -1;
      }
    }
    else {
      return -1;
    }
  }
}

Well, I hope this is useful for someone. I am using a payment plaftorm, ALLOPASS, for SMS micropayments. There is no module for interacting with it in drupal, but it is quite an easy thing. I am not a web programmer, but I have managed to solve communicating with ALLOPASS from my drupal site. If someone wants to create such a moduled solution, I am open to sending my solution to the person who wants to automate it (my solution must be handcoded into every pay node, which is far from the ideal).