Added packagekit backend for update notifications

i3pystatus/updates/packagekit.py

@@ -0,0 +1,31 @@
+import os
+
+from i3pystatus.core.command import run_through_shell
+from i3pystatus.updates import Backend
+
+
+class PackageKit(Backend):
+    """
+    Gets update count for distributions using PackageKit.
+
+    At the moment, it works with english localization, only.
+    """
+
+    @property
+    def updates(self):
+        command = "pkcon get-updates -p"
+        pk = run_through_shell(command.split())
+
+        out = pk.out.splitlines(True)
+        resultStrings = ("Security", "Bug fix", "Enhancement")
+        out = "".join([line for line in out[out.index("Results:\n") + 1:]
+                       if line.startswith(resultStrings)])
+        return out.count("\n"), out
+
+Backend = PackageKit
+
+if __name__ == "__main__":
+    """
+    Call this module directly; Print the update count and notification body.
+    """
+    print("Updates: {}\n\n{}".format(*Backend().updates))