Python Gtk3 Steam client

cornichon.py

#!/usr/bin/env python
import gi
gi.require_version('Gtk', '3.0')
from gi.repository import GdkPixbuf, Gtk, Soup
import glob

class LocalSteam:

    @property
    def installed_games(self):
        """List of identifiers for installed games"""
        for game in glob.glob('/home/ork/.local/share/Steam/steamapps/common/*/steam_appid.txt'):
            with open(game, 'rb') as f:
                yield int(f.readlines()[0])

def add_cb(source_object, res, flowbox):
    data = source_object.send_finish(res)
    pix = GdkPixbuf.Pixbuf.new_from_stream(data)
    print(pix.get_width())
    flowbox.add(Gtk.Image.new_from_pixbuf(pix))
    flowbox.show_all()
    
class Cornichon:

    handlers = {
        "onDeleteWindow": Gtk.main_quit
    }

    def __init__(self):
        self.session = Soup.Session()
        self._build('interface.glade')
        self.window.show_all()
        Gtk.main()

    def _build(self, interface_file):
        builder = Gtk.Builder()
        builder.add_from_file(interface_file)
        builder.connect_signals(self.handlers)

        self.window = builder.get_object('window')
        self.flowbox = builder.get_object('flowbox')

        for banner in glob.glob('banners/*'):
            # self.flowbox.add(Gtk.Image.new_from_file(banner))
            pass

        steam = LocalSteam()
        for game in steam.installed_games:
            res = self.session.request_http('GET', "http://cdn.akamai.steamstatic.com/steam/apps/{}/header.jpg".format(game))
            ins = res.send_async(callback=add_cb, user_data=self.flowbox)


if __name__ == '__main__':
    Cornichon()

interface.glade

<?xml version="1.0" encoding="UTF-8"?>
<!-- Generated with glade 3.20.0 -->
<interface>
  <requires lib="gtk+" version="3.20"/>
  <object class="GtkWindow" id="window">
    <property name="can_focus">False</property>
    <property name="title" translatable="yes">Cornichon</property>
    <signal name="destroy" handler="onDeleteWindow" swapped="no"/>
    <child>
      <object class="GtkFlowBox" id="flowbox">
        <property name="visible">True</property>
        <property name="can_focus">False</property>
        <property name="homogeneous">True</property>
      </object>
    </child>
  </object>
</interface>