Modernize examples

[monnerat]

The example extension scripts need to be in sync with new versions of
referenced foreign packages.
This commit also makes them compatible with Python version 3 (retaining
Python 2 compatibility).
An additional example extension "mixed" is added: it implements all caja
extension features and can also be used as a new extension pattern. See
source header comment for a description.

Ref: #34 (comment)

Tested successfully with Fedora 27 x86_64 and Fedora 29 x86_64 with update from PR #34

[raveit65]

How do you use the examples?
...i never did that in all that years :)

[raveit65]

Got it, the examples needs to be copied to /usr/share/caja-python/extensions/
....i never saw location-widget on the desktop :)

[monnerat]

How do you use the examples?

See https://github.com/mate-desktop/python-caja/blob/master/examples/README

Personally, in terminal 1:

su
cp extension-file.py /usr/share/caja-python/extensions/

In terminal 2 (as normal user):
killall caja; caja &

Don't forget to remove the extension and restart caja as above after finishing working with it !

[raveit65]

LGTM,
tested with python-caja build against python2 an python3.
I used #34 for testing examples with python3.
Looks ready to go.

[vkareh]

This works for me, I have way to many plugins running on caja now :D (I'll remove them)

[monnerat]

Thanks for merge!

[monsta]

Hmm... can we just use some other method from GFile to get the filename? It would keep the code simple as before.

[monnerat]

can we just use some other method from GFile to get the filename?

Yes we can, although I'm not convinced this is simpler (I've searched several minutes to find this unobvious solution):

if file.get_uri_scheme() == 'file':
    self.bgsettings[BACKGROUND_KEY] = file.get_location().get_path()

It also has the advantage of not using urllib.

Approved? If yes, I'll submit a PR.

[monsta]

I didn't know it would be more complex in Python. I looked at C API docs, there's g_file_get_path available. No "get_location" function is mentioned.

[monnerat]

I didn't know it would be more complex in Python. I looked at C API docs, there's g_file_get_path available. No "get_location" function is mentioned.

In fact, the value is a CajaFileInfo that does not expose a get_path method. By playing a bit with it, I found get_location that returns a GLocalFile, subclass of Gfile. CajaFileInfo.get_name() returns the unquoted basename only.
I've locally converted the examples to only use CajaFileInfo.get_name() and CajaFileInfo.get_location()get_path() and get rid of the (python 2/3 incompatible) urllib stuff. Would you have a PR for it ?

[monsta]

Ok, I didn't know it was CajaFileInfo... If .get_location().get_path() would do it, I'm fine with using it.