2011-08-13 00:33:32 +00:00
|
|
|
.. index:: XMLStream, BaseXMPP, ClientXMPP, ComponentXMPP
|
|
|
|
|
|
2014-07-17 12:19:04 +00:00
|
|
|
Slixmpp Architecture
|
2011-08-13 00:33:32 +00:00
|
|
|
======================
|
|
|
|
|
|
2014-07-17 12:19:04 +00:00
|
|
|
The core of Slixmpp is contained in four classes: ``XMLStream``,
|
2011-08-13 00:33:32 +00:00
|
|
|
``BaseXMPP``, ``ClientXMPP``, and ``ComponentXMPP``. Along side this
|
|
|
|
|
stack is a library for working with XML objects that eliminates most
|
|
|
|
|
of the tedium of creating/manipulating XML.
|
|
|
|
|
|
|
|
|
|
.. image:: _static/images/arch_layers.png
|
|
|
|
|
:height: 300px
|
|
|
|
|
:align: center
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
.. index:: XMLStream
|
|
|
|
|
|
|
|
|
|
The Foundation: XMLStream
|
|
|
|
|
-------------------------
|
2014-07-17 12:19:04 +00:00
|
|
|
:class:`~slixmpp.xmlstream.xmlstream.XMLStream` is a mostly XMPP-agnostic
|
2011-11-22 23:25:24 +00:00
|
|
|
class whose purpose is to read and write from a bi-directional XML stream.
|
|
|
|
|
It also allows for callback functions to execute when XML matching given
|
|
|
|
|
patterns is received; these callbacks are also referred to as :term:`stream
|
|
|
|
|
handlers <stream handler>`. The class also provides a basic eventing system
|
|
|
|
|
which can be triggered either manually or on a timed schedule.
|
2011-08-13 00:33:32 +00:00
|
|
|
|
|
|
|
|
The Main Threads
|
|
|
|
|
~~~~~~~~~~~~~~~~
|
2014-07-17 12:19:04 +00:00
|
|
|
:class:`~slixmpp.xmlstream.xmlstream.XMLStream` instances run using at
|
2011-11-22 23:25:24 +00:00
|
|
|
least three background threads: the send thread, the read thread, and the
|
|
|
|
|
scheduler thread. The send thread is in charge of monitoring the send queue
|
|
|
|
|
and writing text to the outgoing XML stream. The read thread pulls text off
|
|
|
|
|
of the incoming XML stream and stores the results in an event queue. The
|
|
|
|
|
scheduler thread is used to emit events after a given period of time.
|
2011-08-13 00:33:32 +00:00
|
|
|
|
|
|
|
|
Additionally, the main event processing loop may be executed in its
|
2014-07-17 12:19:04 +00:00
|
|
|
own thread if Slixmpp is being used in the background for another
|
2011-08-13 00:33:32 +00:00
|
|
|
application.
|
|
|
|
|
|
|
|
|
|
Short-lived threads may also be spawned as requested for threaded
|
|
|
|
|
:term:`event handlers <event handler>`.
|
|
|
|
|
|
|
|
|
|
How XML Text is Turned into Action
|
|
|
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
|
To demonstrate the flow of information, let's consider what happens
|
|
|
|
|
when this bit of XML is received (with an assumed namespace of
|
|
|
|
|
``jabber:client``):
|
|
|
|
|
|
|
|
|
|
.. code-block:: xml
|
|
|
|
|
|
|
|
|
|
<message to="user@example.com" from="friend@example.net">
|
|
|
|
|
<body>Hej!</body>
|
|
|
|
|
</message>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1. **Convert XML strings into objects.**
|
|
|
|
|
|
|
|
|
|
Incoming text is parsed and converted into XML objects (using
|
|
|
|
|
ElementTree) which are then wrapped into what are referred to as
|
|
|
|
|
:term:`Stanza objects <stanza object>`. The appropriate class for the
|
|
|
|
|
new object is determined using a map of namespaced element names to
|
|
|
|
|
classes.
|
|
|
|
|
|
2014-07-17 12:19:04 +00:00
|
|
|
Our incoming XML is thus turned into a :class:`~slixmpp.stanza.Message`
|
2011-11-22 23:25:24 +00:00
|
|
|
:term:`stanza object` because the namespaced element name
|
|
|
|
|
``{jabber:client}message`` is associated with the class
|
2014-07-17 12:19:04 +00:00
|
|
|
:class:`~slixmpp.stanza.Message`.
|
2011-08-13 00:33:32 +00:00
|
|
|
|
|
|
|
|
2. **Match stanza objects to callbacks.**
|
|
|
|
|
|
|
|
|
|
These objects are then compared against the stored patterns associated
|
|
|
|
|
with the registered callback handlers. For each match, a copy of the
|
|
|
|
|
:term:`stanza object` is paired with a reference to the handler and
|
|
|
|
|
placed into the event queue.
|
|
|
|
|
|
2014-07-17 12:19:04 +00:00
|
|
|
Our :class:`~slixmpp.stanza.Message` object is thus paired with the message stanza handler
|
2011-11-22 23:25:24 +00:00
|
|
|
:meth:`BaseXMPP._handle_message` to create the tuple::
|
2011-08-13 00:33:32 +00:00
|
|
|
|
|
|
|
|
('stanza', stanza_obj, handler)
|
|
|
|
|
|
|
|
|
|
3. **Process the event queue.**
|
|
|
|
|
|
2014-07-17 12:19:04 +00:00
|
|
|
The event queue is the heart of Slixmpp. Nearly every action that
|
2011-08-13 00:33:32 +00:00
|
|
|
takes place is first inserted into this queue, whether that be received
|
|
|
|
|
stanzas, custom events, or scheduled events.
|
|
|
|
|
|
|
|
|
|
When the stanza is pulled out of the event queue with an associated
|
|
|
|
|
callback, the callback function is executed with the stanza as its only
|
|
|
|
|
parameter.
|
|
|
|
|
|
|
|
|
|
.. warning::
|
2011-11-22 23:25:24 +00:00
|
|
|
The callback, aka :term:`stream handler`, is executed in the main event
|
2011-08-13 00:33:32 +00:00
|
|
|
processing thread. If the handler blocks, event processing will also
|
|
|
|
|
block.
|
|
|
|
|
|
|
|
|
|
4. **Raise Custom Events**
|
|
|
|
|
|
|
|
|
|
Since a :term:`stream handler` shouldn't block, if extensive processing
|
|
|
|
|
for a stanza is required (such as needing to send and receive an
|
2014-07-17 12:19:04 +00:00
|
|
|
:class:`~slixmpp.stanza.Iq` stanza), then custom events must be used.
|
2011-11-22 23:25:24 +00:00
|
|
|
These events are not explicitly tied to the incoming XML stream and may
|
|
|
|
|
be raised at any time. Importantly, these events may be handled in their
|
|
|
|
|
own thread.
|
2011-08-13 00:33:32 +00:00
|
|
|
|
|
|
|
|
When the event is raised, a copy of the stanza is created for each
|
2011-11-22 23:25:24 +00:00
|
|
|
handler registered for the event. In contrast to :term:`stream handlers
|
|
|
|
|
<stream handler>`, these functions are referred to as :term:`event
|
|
|
|
|
handlers <event handler>`. Each stanza/handler pair is then put into the
|
|
|
|
|
event queue.
|
2011-08-13 00:33:32 +00:00
|
|
|
|
|
|
|
|
.. note::
|
|
|
|
|
It is possible to skip the event queue and process an event immediately
|
|
|
|
|
by using ``direct=True`` when raising the event.
|
|
|
|
|
|
2011-11-22 23:25:24 +00:00
|
|
|
The code for :meth:`BaseXMPP._handle_message` follows this pattern, and
|
2011-08-13 00:33:32 +00:00
|
|
|
raises a ``'message'`` event::
|
|
|
|
|
|
|
|
|
|
self.event('message', msg)
|
|
|
|
|
|
|
|
|
|
The event call then places the message object back into the event queue
|
|
|
|
|
paired with an :term:`event handler`::
|
|
|
|
|
|
|
|
|
|
('event', 'message', msg_copy1, custom_event_handler_1)
|
|
|
|
|
('event', 'message', msg_copy2, custom_evetn_handler_2)
|
|
|
|
|
|
|
|
|
|
5. **Process Custom Events**
|
|
|
|
|
|
|
|
|
|
The stanza and :term:`event handler` are then pulled from the event
|
|
|
|
|
queue, and the handler is executed, passing the stanza as its only
|
|
|
|
|
argument. If the handler was registered as threaded, then a new thread
|
|
|
|
|
will be spawned for it.
|
|
|
|
|
|
|
|
|
|
.. note::
|
|
|
|
|
Events may be raised without needing :term:`stanza objects <stanza object>`.
|
|
|
|
|
For example, you could use ``self.event('custom', {'a': 'b'})``.
|
|
|
|
|
You don't even need any arguments: ``self.event('no_parameters')``.
|
|
|
|
|
However, every event handler MUST accept at least one argument.
|
|
|
|
|
|
|
|
|
|
Finally, after a long trek, our message is handed off to the user's
|
|
|
|
|
custom handler in order to do awesome stuff::
|
|
|
|
|
|
|
|
|
|
msg.reply()
|
|
|
|
|
msg['body'] = "Hey! This is awesome!"
|
|
|
|
|
msg.send()
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
.. index:: BaseXMPP, XMLStream
|
|
|
|
|
|
|
|
|
|
Raising XMPP Awareness: BaseXMPP
|
|
|
|
|
--------------------------------
|
2014-07-17 12:19:04 +00:00
|
|
|
While :class:`~slixmpp.xmlstream.xmlstream.XMLStream` attempts to shy away
|
|
|
|
|
from anything too XMPP specific, :class:`~slixmpp.basexmpp.BaseXMPP`'s
|
2011-11-22 23:25:24 +00:00
|
|
|
sole purpose is to provide foundational support for sending and receiving
|
|
|
|
|
XMPP stanzas. This support includes registering the basic message,
|
|
|
|
|
presence, and iq stanzas, methods for creating and sending stanzas, and
|
|
|
|
|
default handlers for incoming messages and keeping track of presence
|
|
|
|
|
notifications.
|
2011-08-13 00:33:32 +00:00
|
|
|
|
|
|
|
|
The plugin system for adding new XEP support is also maintained by
|
2014-07-17 12:19:04 +00:00
|
|
|
:class:`~slixmpp.basexmpp.BaseXMPP`.
|
2011-08-13 00:33:32 +00:00
|
|
|
|
|
|
|
|
.. index:: ClientXMPP, BaseXMPP
|
|
|
|
|
|
|
|
|
|
ClientXMPP
|
|
|
|
|
----------
|
2014-07-17 12:19:04 +00:00
|
|
|
:class:`~slixmpp.clientxmpp.ClientXMPP` extends
|
|
|
|
|
:class:`~slixmpp.clientxmpp.BaseXMPP` with additional logic for connecting
|
2011-11-22 23:25:24 +00:00
|
|
|
to an XMPP server by performing DNS lookups. It also adds support for stream
|
2011-08-13 00:33:32 +00:00
|
|
|
features such as STARTTLS and SASL.
|
|
|
|
|
|
|
|
|
|
.. index:: ComponentXMPP, BaseXMPP
|
|
|
|
|
|
|
|
|
|
ComponentXMPP
|
|
|
|
|
-------------
|
2014-07-17 12:19:04 +00:00
|
|
|
:class:`~slixmpp.componentxmpp.ComponentXMPP` is only a thin layer on top of
|
|
|
|
|
:class:`~slixmpp.basexmpp.BaseXMPP` that implements the component handshake
|
2011-11-22 23:25:24 +00:00
|
|
|
protocol.
|
