106 lines
4.2 KiB
Text
106 lines
4.2 KiB
Text
Overview
|
||
========
|
||
|
||
NOTE: This is not an introduction to XMPP, but to poezio
|
||
|
||
|
||
Global overview
|
||
---------------
|
||
|
||
Poezio is an application that has three main layers, mostly separated in three
|
||
different python modules: _core_, _tabs_, and _windows_. An UML diagram of
|
||
Poezio would be inneficient, cluttered, or incomplete, so there is none, if
|
||
that bugs you.
|
||
|
||
image::../../images/layers.png["The application layers", title="Layers"]
|
||
|
||
_Core_ is mostly a “global” object containing the state of the application at
|
||
any time, it contains the global commands, the xmpp event handlers, the list
|
||
of open tabs, etc. Most objects in poezio have a self.core attribute
|
||
referencing the _Core_ (it’s a singleton, so there is never more than one
|
||
instance). _Core_ also contains the main loop of the application, which then
|
||
dispatchs the I/O events (keypress) to the appropriate methods.
|
||
|
||
|
||
But the main loop is not the most important thing in poezio; because it is an
|
||
IM client, it is essentially event-driven. The event part is handled by
|
||
SleekXMPP, which is the library we chose after moving away from xmpppy.
|
||
|
||
|
||
_Tabs_ are the second layer of poezio, but the first dealing with the UI: each
|
||
_Tab_ is a layout of several _windows_, it contains tab-specific commands,
|
||
tab-specific keybinds, and it has methods in order for core to
|
||
interact with it, and some methods are only proxies for the methods of a
|
||
_window_
|
||
|
||
Example scenario: If someone presses the key PageUp, then Core will call the
|
||
appropriate method on the current _Tab_, which will in turn, if it implements the
|
||
method (inherited empty from the Tab class), call a scrolling method from the
|
||
appropriate _window_.
|
||
|
||
All tabs types inherit from the class _Tab_, and the _Tabs_ featuring
|
||
chat functionnality will inherit fro _ChatTab_ (which inherits from _Tab_).
|
||
|
||
Examples of _Tabs_: MUCTab, XMLTab, RosterTab, MUCListTab, etc…
|
||
|
||
Event handlers
|
||
--------------
|
||
|
||
The events handlers are registered right at the start of poezio, and then
|
||
when a matching stanza is received, the handler is called in a separate thread
|
||
from the main loop. The handlers are in _Core_, and then they call the
|
||
appropriate methods in the corresponding _tabs_.
|
||
|
||
Example scenario: if a message is received from a MUC, then the _Core_ handler
|
||
will identify the _Tab_, and call the relevant handler from this _Tab_, this tab
|
||
will in turn, add the message to the buffer, which will then add it to the
|
||
relevant _windows_.
|
||
|
||
NOTE: All the _windows_ that deal with received or generated text are linked
|
||
to a _text_buffer_, in order to rebuild all the display lines from the
|
||
sources if necessary. This also enables us to have several _windows_
|
||
presenting the same text, even if they are not of the same size and layout.
|
||
|
||
|
||
Commands and completion
|
||
-----------------------
|
||
|
||
Commands are quite straightforward: those are methods that take a string as a
|
||
parameter, and they do stuff.
|
||
|
||
From an user point of view, the methods are entered like that:
|
||
|
||
==================================
|
||
|
||
/command arg1 arg2
|
||
|
||
or
|
||
|
||
/command "arg1 with spaces" arg2
|
||
|
||
==================================
|
||
|
||
However, when creating a command, you wil deal with _one_ str, no matter what.
|
||
There are utilities to deal with it (common.shell_split), but it is not always
|
||
necessary. Commands are registered in the _commands_ dictionnary of a tab
|
||
structured as key (command name) -> tuple(command function, help string, completion).
|
||
|
||
|
||
Completions are a bit tricky, but it’s easy once you get used to it:
|
||
|
||
They take an _Input_ (a _windows_ class) as a parameter, named the_input
|
||
everywhere in the sources. To effectively have a completion, you have to call
|
||
_the_input.auto_completion()_ at the end of the function.
|
||
|
||
*the_input.auto_completion(completion_list, after='', quote=True)*:
|
||
Set the input to iterate over _completion_list_ when the user hits tab, insert
|
||
_after_ after the completed item, and surround the item with double quotes or
|
||
not.
|
||
|
||
There is no method to find the current argument in the input (although the
|
||
feature is planned), so you have to assume the current argument is the last,
|
||
and guess it by splitting the string an checking for end-space.
|
||
|
||
You can look for examples in the sources, all the possible cases are
|
||
covered (single-argument, complex arguments with spaces, several arguments,
|
||
etc…)
|