Embedding flash in Facebook link posts

If you want to have custom flash movies embeded in Facebook posts that link to your website, like these one from YouTube or SoundCloud:

 

It's fairly simple. 

BUT, it requires a SSL certificate, so that your website works over HTTPS, without browsers whining about security.

Here's what you do.

You've heard of OpenGraph protocol, right? Right. So, that's all there is to it. Proper metadata in the HTML of your website will instruct Facebook to include your flash movie, like this:

<meta property="og:title" content="Aljažev stolp | Triglav (2864m) | VR panorama"/>
<meta property="og:video" content="http://kafol.net/pano/aljazev-stolp/aljazev.stolp.swf"/> 
<meta property="og:type" content="movie"/>
<meta property="og:url" content="http://kafol.net/pano/aljazev-stolp/"/>
<meta property="og:image" content="http://kafol.net/pano/aljazev-stolp/preview.jpg"/>
<meta property="og:description" content="VR (virtual reality) panorama pri Aljaževem stolpu na vrhu Triglava. Panorama je posneta brez stativa."/>
<meta property="og:video:type" content="application/x-shockwave-flash" />
<meta property="og:video:width" content="400" />
<meta property="og:video:height" content="300" />

The next part depends on what the flash movie actually does. If it's a movie/music player that fetches media from other sources, or even an other part of your website, you'll need to configure crossdomain.xml. You put that file on the root of your website.

Here's a very liberal example, but fine for testing:

<?xml version="1.0" ?>
<cross-domain-policy>
<allow-access-from domain="*" />
</cross-domain-policy>

PHP:: socket_select(), socket_write() and socket_recv()

As it was already said, some clients need \0 character to end transmission, for example Flash's XMLSocket.

You should also be prepared to read less data than you have requested.

Here is an example of a socket buffer - it's an array which has socket resources for keys and an array of a timestamp and recieved data as values.

I find that the best practice for sending data is trailing it with a new line and zero character (\n\0), because you will probably have different types of clients which behave differently for reading data from sockets. Some need a \n to fire an event, some need \0.

For recieving data, sometimes you will get splitted data - this can hapen because the buffer is full (in my example 8192 bytes) or it just gets broken during transmission in lower levels.

Sometimes you can read two messages at once, but they have a zero character in between, so you can just use preg_split() to split the messages. The second message may not be complete, so you add it to your buffer.

 const message_delimiter = "\n\0";

 /*
  * Clear socket buffers older than 1 hour
  */
 function clear_buffer() {
  foreach($this->buffer as $key=>$val) {
   if(time() - $val['ts'] > 3600) {
    unset($this->buffer[$key]);
   }
  }
 }

 /*
  * Add data to a buffer
  */
 function buffer_add($sock,$data) {
  if(!isset($this->buffer[$sock])) {
   $this->buffer[$sock]['data'] = '';
  }

  $this->buffer[$sock]['data'] .= $data;
  $this->buffer[$sock]['ts'] = time();
 }

 function buffer_get($sock) {
  // split buffer by the end of string
  $lines = preg_split('/\0/',$this->buffer[$sock]['data']);

  // reset buffer to the last line of input
  // if the buffer was sent completely, the last line of input should be
  // an empty string
  $this->buffer[$sock]['data'] = trim($lines[count($lines)-1]);

  if(!empty($this->buffer[$sock]['data'])) {
   debug("buffer is not empty for $sock, len: ".strlen($this->buffer[$sock]['data']));
  }

  // remove the last line of input (incomplete data)
  // parse any complete data
  unset($lines[count($lines)-1]);

  // return only the fully sent data
  return $lines;
 }

 function read(&$sock,$len=8192,$flag=MSG_DONTWAIT) {
  $lines = array();

  $this->clear_buffer();

  $bytes_read = @socket_recv($sock,$read_data,$len,$flag);

  if ($bytes_read === false || $bytes_read == 0) {
   return false;
  } else {
   debug("recv: $read_data");
   $this->buffer_add($sock,$read_data);
   return $this->buffer_get($sock);
  }
 }

 /*
  * Write to a socket
  * add a newline and null character at the end
  * some clients don't read until new line is recieved
  *
  * try to send the rest of the data if it gets truncated
  */
 function write(&$sock,$msg) {
  $msg = $msg.self::message_delimiter;
  $length = strlen($msg);
  while(true) {
   $sent = @socket_write($sock,$msg,$length);
   if($sent <= 0) {
    return false;
   }
   if($sent < $length) {
    $msg = substr($msg, $sent);
    $length -= $sent;
    debug("Message truncated: Resending: $msg");
   } else {
    return true;
   }
  }
  return false;
 }

Flash wmode (transparent/opaque/window) z-index

In flash player 9 and below there was a problem with the object's z-index if the wmode was set to window.

When this option is set to transparent, it fixes the z-index issue, but messes up the keyboard layout and mouse wheel events in flash object. Flash player 10.1 fixes the keyboard layout issue.

Workaround
Setting wmode to opaque keeps the mouse wheel functionality and z-index of absolute elements on the page, but only if you set the background color for the element!

Having a transparent background (or setting the opacity attribute in CSS) (still) does not solve the issue.

ActionScript: Passing parameters to onRelease and other event functions

As it turns out, you can't use parameters directly when defining an event function, for example:

myMovie.onRelease = function(param1,param2,param3) {
   //my code
}

The example above will generate a compiler error. This won't work either:

var = 1;
var2 = "something else";
myMovie.onRelease = function() {
   //var and var1 are unaccessible at this point
}

The solution for this is simple, yet effective. You need to define your paramaters to a movieclip, so that you can reach them with the operator "this".

myMovie.param1 = "something";
mymovie.param2 = "something else";
myMovie.onRelease = function() {
   trace(this.param1);
   trace(this.param2);
}

ActionScript: Controling volume of all sounds

By creating a sound object with no target on the highest level, you can control volume of all sounds on the stage.

var s:Sound = new Sound();
s.setVolume(0);

This will mute all sounds. The setVolume() parameter is given as percentage, so the value is between 0 and 100 where 0 is muted.