[Gazpacho] Plugin system proposal

[Lorenzo Gil Sanchez]

El lun, 05-06-2006 a las 19:14 -0300, Johan Dahlin escribió:
> > What's the difference between a widget library and a plugin
> 
> > Unfortunately right now widget library are somewhere called plugins and
> > it makes this classification not obvious.
> 
> Hopefully we can convert the libraries to be plugins in the future, so we
> don't need to have separate infrastructure for both.
> 
> > Anatomy of a plugin
> 
> > * A __init__.py file. Otherwise it won't be a Python package. In this
> > file,
> >   the plugin metadata is located in the form of the following variables:
> 
> I'm not sure if this kind of metadata should live in the source code, I
> think it's better to let it be in an .ini file so we don't have to
> load any python code to fetch information about a plugin.
> Check how gedit does this.

They use .desktop files which may be an interesting option

> 
> > * A plugin.py file where a subclass of gazpacho.plugin.Plugin should
> >   be defined. The name of this class should be the same as the string
> >   'plugin_class' found in the __init__.py file
> 
> just use namedAny to fetch the python object, it can then be a package or
> a module.

Are you suggesting to depend on Twisted or is that function in the
standard Python library?

> 
> > Plugin Manager
> > --------------
> > The Plugin Manager is instantiated by Gazpacho at start up time and it
> > loads all the plugins. This mean that it maintains a list of PluginInfo
> > objects. Each PluginInfo object has meta information about the plugin
> > such as:
> > 
> >    - Plugin Id
> 
> Name is probably better here.
> 
> >    - Plugin module
> >    - Plugin class name
> 
> It seems to me that you don't need both of these.
> 
> Version too perhaps?

Sure

> 
> > Plugin base class (gazpacho.plugin.Plugin)
> 
> > class GazpachoPlugin(object):
> > 
> >   def get_ui(self):
> >     """Returns the UI string for this plugin"""
> > 
> >   def get_actions(self):
> >     """Returns a list of actions that match the UI string definition"""
> > 
> >   def on_object_selected(self):
> >     """This will be called every time an object/widget is selected"""
> > 
> >   def on_project_changed(self):
> >     """This will be called when a project is opened or selected"""
> 
> You don't need any of these, instead pass in the application object and let
> the plugin developer fetch projects/selections/whatever themselves.
> They would also be responsible for merging/removing actions and xml from the
>  ui manager. Leave as much freedom to the plugin writers as possible.
> 

I like the GEdit plugin API. It just have 3 important methods:

- Activate

- Deactivate

- Get Configuration Dialog