:orphan:


Flash Policy Transport
======================

Quick Links: :doc:`Transport Endpoints <Transport-Endpoints>` 

Old Web browsers like IE8 and IE9 do no support WebSocket natively.
*One* option to work around is using
`web-socket-js <https://github.com/gimite/web-socket-js>`__, a WebSocket
implementation written in Adobe Flash.

When using Adobe Flash to open a TCP socket, Flash will only allow the
(outgoing) TCP connection *after* checking for a so called *Flash policy
file* on the target server. And this policy file needs to be served on
TCP port 843.

Crossbar.io includes a *pseudo transport* for serving a Flash policy
file. It is a *pseudo* transport, since in itself, it does not provide a
WAMP transport, but its only purpose is to serve the Flash policy.

    The `Crossbar.io examples
    repository <https://github.com/crossbario/crossbar-examples>`__
    contains a `working
    example <https://github.com/crossbario/crossbar-examples/tree/master/flash>`__
    for this.

Configuration
-------------

In the configuration (``.crossbar/config.json``), you'll find:

.. code:: json

    {
       "workers": [
          {
             "type": "router",
             "transports": [
                {
                   "type": "flashpolicy",
                   "allowed_domain": "*",
                   "allowed_ports": [8080],
                   "endpoint": {
                      "type": "tcp",
                      "port": 843
                   }
                }
             ]
          }
       ]
    }

--------------

Usage
-----

The only difference client side (in the HTML) versus a standard client
is that you now include the Flash implementation *before* AutobahnJS:

.. code:: html

    <!-- Adobe Flash implementation of WebSocket: https://github.com/gimite/web-socket-js -->
    <script>
       WEB_SOCKET_SWF_LOCATION = "WebSocketMain.swf";
       // set the following to false for production, otherwise
       // it _always_ uses Flash
       WEB_SOCKET_FORCE_FLASH = true;
       WEB_SOCKET_DEBUG = true;
    </script>
    <script src="swfobject.js"></script>
    <script src="web_socket.js"></script>

    <!-- AutobahnJS -->
    <script src="autobahn.min.js"></script>


Configuration
-------------


+-----------------+--------------------------------------------------------------------------------------------------------------------------------------+
| option          | description                                                                                                                          |
+=================+======================================================================================================================================+
| id              | ID of the transport within the running node (default: transport<N> where N is numbered automatically starting from 1)                |
+-----------------+--------------------------------------------------------------------------------------------------------------------------------------+
| type            | Type of transport - must be "flash".                                                                                                 |
+-----------------+--------------------------------------------------------------------------------------------------------------------------------------+
| endpoint        | Listening endpoint for transport. See :doc:`Transport Endpoints<Transport-Endpoints>` for configuration                              |
+-----------------+--------------------------------------------------------------------------------------------------------------------------------------+
| allowed_domain  | Domain (a string) clients should be allowed to connect to or null to allow any domain (default: null)                                |
+-----------------+--------------------------------------------------------------------------------------------------------------------------------------+
| allowed_ports   | List of ports (a list of integers from [1, 65535]) clients should be allowed to connect to or null to allow any port (default: null) |
+-----------------+--------------------------------------------------------------------------------------------------------------------------------------+
| debug           | Turn on debug logging for this transport instance (default: false).                                                                  |
+-----------------+--------------------------------------------------------------------------------------------------------------------------------------+