Simple Orca Plugin System

With the
Simple Orca Plugin System
(SOPS) you can extend the functionality of the Orca screen reader (
orca
).
It offers the possibility to add plug-ins in nearly any programming language in an easy way.
The settings for the plug-ins are controlled via the filename.
Installation
Install
the package
simpleorcapluginsystem-git
AUR
.
To setup the plug-in system for the current user, run:
$ /usr/share/SOPS/install-for-current-user.sh
Administration
Basics
The Installation path. This contains the default plug-ins, the documentation,the plugin loader and the administration tools:
/usr/share/SOPS/
The path for user plug-ins is:
~/.config/SOPS/plugins-available/
The following path is used for all enabled (active) plug-ins. All plug-ins in that folder will be loaded, if they are valid:
~/.config/SOPS/plugins-enabled/
Administration tools
The tools are located in the "tools" folder beneath the installation directory. The following command enables/activates a plug-in, but you have to rename the filename to create a shortcut and pass a command to the plug-in:
$ ./ensop <pluginname>
The command to disable and unload a plug-in is:
$ ./dissop <pluginname>
Both commands basically just create or delete links in
~./.config/SOPSP/plugins-enabled
and make the plug-ins executable. You have to configure the plug-ins manually.
Restart Orca to reload the plug-ins after changes. 
SOPS also provides a plug-in manager, it is available after the installation.
To open the plug-in manager use
orca+ctrl+p
while Orca is running.
It can be used to activate, deactivate, install or configure plug-ins.
Orca gets re-started automatically after closing the plug-in manager.
Plug-ins
Tip
You can find some fully predefined example plugins in
/usr/share/SOPS/examples
.
Structure of the filename
The shortcut, plug-in type and preference of a plug-in are controlled by its filename. 
The descriptive part of the filename has to be separated from the preferences part with
__-__
. 
The commands, modifier and the key has to be separated by
__+__
.
<description>__-__[<command>__+__command...][__+__<modifier>__+__<modifier>__+__key_<key>].ext
Run a plug-in
There are two different ways to run a plug-in:
shortcut (See
#Modifiers/ Shortcuts
)
exec run once when the plug-in loads. (See
#Commands/ Preferences
)
If none of those are present. the plug-in does not load. 
There are some more
#Commands/ Preferences
to control the behaviour of a plug-in.
Modifiers/ Shortcuts
With modifiers you can set different shortcut combinations for a
key
.
You always have to press the Orca-modifier.
The order of the three modifier keys does not matter:
control
is the modifier for the
ctrl
key on the keyboard
shift
is the modifier for the
shift
key on the keyboard
alt
is the modifier for the
alt
key on the keyboard
key_<key>
defines the basic shortcut that is used for the plug-in, maybe together with the defined modifiers (example_plugin__-__key_d.sh uses
orca+d
).
Valid shortcuts
Only a few combinations of modifiers are valid. Those are predefined by Orca.
Valid combinations are:
alt
i.e.
description__-__alt__+__key_y.sh
control
i.e.
description__-__control__+__key_b.sh
shift
i.e.
description__-__shift__+__key_c.sh
control + alt
i.e.
description__-__control__+__alt__+__key_w.py
shift + alt
i.e.
description__-__shift__+__alt__+__key_y.sh
As
key_<key>
you can use every alphanumerical key.
Commands/ Preferences
Preferences for plug-ins are called commands. A command defines the action to pass to the plug-in. 
With commands you control the behaviour of the plug-ins. You may add more than one command. The order of the commands does not matter.
You can use them mostly for all kinds of plug-ins.
startnotify
announces "start <description>" before the plug-in is executed. It is useful as feedback for plug-ins with longer progress times. (all plug-ins)
stopnotify
announces "finish <description>". This is useful as feedback for plug-ins with no output. (all plugins)
blockcall
do not start the plug-in in a thread. Be careful, as this locks Orca until the plug-in is finished. By default, plug-ins each run in a dedicated thread. (all plug-ins)
error
announces returned errors. (all plug-ins)
supressoutput
ignores the output of STDOUT. This is useful for plugins that may have a UI and do not pass output to STDOUT. (sub process plug-in only)
parameters_<parameter1> [parameter2] [parameter3]...
passes the parameters to the plug-in. (sub process plug-in only)
exec
run the plug-in once while loading it. Mostly useful as advanced-plug-in. (all plug-ins)
loadmodule
does not load as a sub process plug-in but loads it as advanced plug-in. (advanced plug-in only)
Examples
Plugin name__-__startnotify__+__control__+__alt__+__key_n.sh
Run with
orca+ctrl+alt+n
and announce the start of the process.
PluginName__-__error__+__stopnotify__+__shift__+__key_y.py
Run with
orca+shift+m
and announce the finishing. Does also read occurring errors .
Plugin_Name__-__key_m.py
Run with
orca+m
Plugin_Name__-__exec.py
Run once at starting Orca.
Types of plug-ins
Basically there are two different types of plugins.
Sub process plug-ins
Sub process plug-ins are simple plug-ins and the default type.
They may be any type of application or script that writes to STDOUT or STDERR.
Orca executes the plug-in, reads from STDOUT/ STDERR and announces the result to the user, when the defined shortcut is pressed or the plug-in is executed via
exec
while starting screen reader.
Requirements
Execution permission
key_<key>
or
exec
have to be defined in the filename.
Example
Say "Hello World when pressing
orca+y
:
Filename:
Hello_world__-__key_y.sh
#!/bin/sh
echo "Hello World"
Advanced plug-ins
Those type of plug-ins are loaded with the spec.loader.exec_module. you can load them by using
loadmodule
in the filename. They are fully included into Orca as soon as it starts.
Advanced plug-ins are more powerful, because you are able to work in the Orca context. They are mostly similar to the
orca-customizations.py
.
Requirements
Correct code written in python3
Fileextension
.py
Use
loadmodule
in the filename
key_<key>
or
exec
have to been defined in filename
Example
Configure Orca to speak/braille the word "bang" instead of the "!" while loading the plug-in.
Filename:
replace_chnames__-__loadmodule__+__exec.py
import orca.orca
orca.chnames.chnames["!"] = "bang"
Plug-in hosting
You can also host plug-ins, making them available for installation via the plug-in manager.
If you want to Host plug-ins, read:
/usr/share/SOPS/tools/hosting.txt
The default online resource is:
https://stormdragon.tk/orca-plugins/index.php
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