le-Web.org » Python/PyGTK

PyGTK: Copy a file to clipboard (paste it in Nautilus)

dan — Thu, 04 Dec 2008 10:21:13 +0000

PyGTK provide clipboard functionality for standard targets: text, file(s) and image. Nautilus if does not use the standard URI target for copy/cat/paste file because this target does not provide the desired action (copy or cut).

For copy/cat/paste Nautilus use a special clipboard target named “x-special/gnome-copied-files”. The content of this target is a text with items separated by new line character (“\n”). The first line is the action (“copy” or “cut”) and then one URI per line.

To copy the file /path/abc.txt the target “x-special/gnome-copied-files” contains the text:

copy
file:///path/abc.txt

The class “gtk.Clipboard” has the method

def set_with_data(targets, get_func, clear_func, user_data)

to set the content of the clipboard to any targets and to provide functions for clipboard requests (get/clean).

Using this method I write a simple code to handle copy path to clipboard (gnomeclipboardtools.py):

<br />
<b>Warning</b>:  include(/home2/macadanc/public_html/le-web.org/wp-content/uploads/2008/12/gnomeclipboardtools.py) [<a href='function.include'>function.include</a>]: failed to open stream: No such file or directory in <b>/home2/macadanc/public_html/le-web.org/wp-content/plugins/include-it/plugin.php</b> on line <b>86</b><br />
<br />
<b>Warning</b>:  include() [<a href='function.include'>function.include</a>]: Failed opening '/home2/macadanc/public_html/le-web.org/wp-content/uploads/2008/12/gnomeclipboardtools.py' for inclusion (include_path='.:/usr/share/pear') in <b>/home2/macadanc/public_html/le-web.org/wp-content/plugins/include-it/plugin.php</b> on line <b>86</b><br />

Using it is very simple:

import gnomeclipboardtools
gnomeclipboardtools.clipboard_copy_path( '/path/abc.txt' )

PyGTK: Get GNOME icon associated with a file

dan — Tue, 18 Nov 2008 15:16:55 +0000

If in your application you need to display a list of files/folders it would be nice to display icons near filenames.

Icons are associated with files using mime types. For a file you need to get it’s mime and the get the icon associated with this mime.
The module gnomevfs provides almost all you need:

def gnomevfs.get_mime_type(uri)

Returns a string containing the mime type (ex: for the file “file.tar.gz” the mime is “application/x-compressed-tar”).

def gnomevfs.mime_get_icon(mime_type)

Returns a string with an icon name.

I said almost because gnomevfs.mime_get_icon always returns None (at least in my version).

Since the gnomevfs.get_mime_type works fine I decide to write a little class to associate the mime with the icons.

Gnome use icon names like “gnome-mime-”. Ex: for the mime “application/x-compressed-tar” the gnome icon name is “gnome-mime-application-x-compressed-tar”.

My class try to associate the mime with an icon, by searching for icons with the name:

“gnome-mime-”
if the path is a directory it will try the icon name “folder” and if “folder” don’t exists just returns gtk.STOCK_DIRECTORY
“mime-”
returns gtk.STOCK_FILE

In order to optimize mime to icon association the class use a cache.

<br />
<b>Warning</b>:  include(/home2/macadanc/public_html/le-web.org/wp-content/uploads/2008/11/gnomefileicons.py) [<a href='function.include'>function.include</a>]: failed to open stream: No such file or directory in <b>/home2/macadanc/public_html/le-web.org/wp-content/plugins/include-it/plugin.php</b> on line <b>86</b><br />
<br />
<b>Warning</b>:  include() [<a href='function.include'>function.include</a>]: Failed opening '/home2/macadanc/public_html/le-web.org/wp-content/uploads/2008/11/gnomefileicons.py' for inclusion (include_path='.:/usr/share/pear') in <b>/home2/macadanc/public_html/le-web.org/wp-content/plugins/include-it/plugin.php</b> on line <b>86</b><br />

Using it is very simple:

import gnomefileicons
 
fileicons = gnomefileicons.GnomeFileIcons()
print fileicons.getIcon('/path/file.tar.gz')

PyGTK: How to display a systray icon from a cronjob

dan — Thu, 06 Nov 2008 11:51:58 +0000

It is nice to give some user feedback when someting happen in a background application. For example when a cronjob is running it would be nice to show a systray icon.

When the cron-job runs the DISPLAY environment variable is not defined so your gtk application can’t access to xserver. So before importing pygtk you should check if DISPLAY is defined. If not just define it to default value “:0.0″.

import os
 
#if DISPLAY is not set, then set it to default ':0.0'
if len( os.getenv( 'DISPLAY', '' ) ) == 0:
	os.putenv( 'DISPLAY', ':0.0' )
 
import pygtk
pygtk.require("2.0")

But what happens if your gtk application really can’t connect to the xserver (xserver is not runnig, you are not logged in …). In this case your application should not try to use xserver related functions. For example when I try to use gtk.StatusIcon the application ends with a segmentation fault.

To check if your application can access to xserver just get the default display. If it is None then you can’t access it.

display = gtk.gdk.display_get_default()
if not display is None:
	...

Now, putting all together I made this simple application: notify.py.

<br />
<b>Warning</b>:  include(/home2/macadanc/public_html/le-web.org/wp-content/uploads/2008/11/notify.py) [<a href='function.include'>function.include</a>]: failed to open stream: No such file or directory in <b>/home2/macadanc/public_html/le-web.org/wp-content/plugins/include-it/plugin.php</b> on line <b>86</b><br />
<br />
<b>Warning</b>:  include() [<a href='function.include'>function.include</a>]: Failed opening '/home2/macadanc/public_html/le-web.org/wp-content/uploads/2008/11/notify.py' for inclusion (include_path='.:/usr/share/pear') in <b>/home2/macadanc/public_html/le-web.org/wp-content/plugins/include-it/plugin.php</b> on line <b>86</b><br />

Try it:

python notify.py

Now to try it from cron, you can add it in you crontab to be called every 10 minutes (use full path to notify.py):

( crontab -l; echo "0 * * * * python /FULLPATH/notify.py" ) | crontab -
( crontab -l; echo "10 * * * * python /FULLPATH/notify.py" ) | crontab -
( crontab -l; echo "20 * * * * python /FULLPATH/notify.py" ) | crontab -
( crontab -l; echo "30 * * * * python /FULLPATH/notify.py" ) | crontab -
( crontab -l; echo "40 * * * * python /FULLPATH/notify.py" ) | crontab -
( crontab -l; echo "50 * * * * python /FULLPATH/notify.py" ) | crontab -

Check your crontab:

crontab -l

you should see the lines with “python /FULLPATH/notify.py”.

To remove it from your crontab just call:

crontab -l | grep -v notify.py | crontab -

PyGTK: Allow only one instance of your application (2)

dan — Tue, 04 Nov 2008 11:05:30 +0000

In the post “PyGTK: Allow only one instance of your application” I presented a method to raise a PyGTK application’s window, but the solution was not perfect.

To raise the application’s window (from the application it self), I used the code:

self.window.present_with_time( int(time.time()) )
self.window.present()

gtk.Window.present_with_time(): works all the time but it does not activate the window
gtk.Window.present: it does not works all the time (ex: it does not works if the application shows a modal dialog on the main window), but when it does it activate the window too

Using this method, in the worst case the window is raised but is not activate.

But this method was not good enough for me. I wanted a method that works all the time: raise the window and activate/focut it.
So this is the new solution:

self.window.present_with_time( int(time.time()) )
self.window.window.focus()

gtk.Window.present_with_time(): raise the window
self.window.window.focus(): focus the window

PyGTK: Allow only one instance of your application

dan — Mon, 03 Nov 2008 13:37:41 +0000

In the post “Python: Allow only one instance of your application” I presented a method that works great for non GUI applications. It work’s fine for GUI applications too but if the application is already running the second instance will just quit. What if the application instance’s window is hidden by other window ?

In this case the best behavior is: if the GUI application is already running, the second application raise it and then quit. This provides a better user experience.

I read about gtk.gdk.Window.raise_() method. I don’t know why but it’s working (at least in my case) !!! The application’s window remains behind other windows.

The only working functions that I found, was:

gtk.Window.present_with_time(): works all the time but it does not activate the window
gtk.Window.present: it does not works all the time (ex: it does not works if the application shows a modal dialog on the main window), but when it does it activate the window too

The best way is to call them both. In the worst case the window is raised but is not activate.

The problem with this functions is that it must be called in the application instance, because I didn’t find a way to create a gtk.Window for an external xid (only gtk.gdk.Window). So when the second application starts it must inform the “only” application instance to raise it’s window.

There are different methods to comunicate between applications and I will not discuss them here. A simple and “lazy” solution is to create a file. The application instance will check from time to time if the file exists. If the file exists raise it’s window. We can can write some information in this file so that the application instance can use it.

This is my “Hello World !” application instance: gtkapplicationinstance.py. This application checks every second if it needs to raise itself.

<br />
<b>Warning</b>:  include(/home2/macadanc/public_html/le-web.org/wp-content/uploads/2008/11/gtkapplicationinstance.py) [<a href='function.include'>function.include</a>]: failed to open stream: No such file or directory in <b>/home2/macadanc/public_html/le-web.org/wp-content/plugins/include-it/plugin.php</b> on line <b>86</b><br />
<br />
<b>Warning</b>:  include() [<a href='function.include'>function.include</a>]: Failed opening '/home2/macadanc/public_html/le-web.org/wp-content/uploads/2008/11/gtkapplicationinstance.py' for inclusion (include_path='.:/usr/share/pear') in <b>/home2/macadanc/public_html/le-web.org/wp-content/plugins/include-it/plugin.php</b> on line <b>86</b><br />

Python: Allow only one instance of your application

dan — Thu, 30 Oct 2008 14:00:04 +0000

Multitasking operating systems (all modern operating systems) allow us to execute an applications then once at the same time and this is a great feature. But, in some special cases, you may want to allow only one instance application.

I needed a way for my Back In Time project so I searched on the internet and found a very simple solution: when the application start it looks for a file that contains the “application instance” pid. If the file exists and the pid (from this file) is still valid then the application is already running so this second instance must exit. If not the application can start and save it’s pid in this file.

This is my Python implentation (applicationinstance.py).

<br />
<b>Warning</b>:  include(/home2/macadanc/public_html/le-web.org/wp-content/uploads/2008/10/applicationinstance.py) [<a href='function.include'>function.include</a>]: failed to open stream: No such file or directory in <b>/home2/macadanc/public_html/le-web.org/wp-content/plugins/include-it/plugin.php</b> on line <b>86</b><br />
<br />
<b>Warning</b>:  include() [<a href='function.include'>function.include</a>]: Failed opening '/home2/macadanc/public_html/le-web.org/wp-content/uploads/2008/10/applicationinstance.py' for inclusion (include_path='.:/usr/share/pear') in <b>/home2/macadanc/public_html/le-web.org/wp-content/plugins/include-it/plugin.php</b> on line <b>86</b><br />

If you want to use it in your application, all you have to do is:

from applicationinstance import *
 
#create application instance
appInstance = ApplicationInstance( '/tmp/myapplication.pid' )
 
# ... execute your application
 
#remove pid file
appInstance.exitApplication()