Improved state saving logic

libremsonic/app.py

@@ -1,11 +1,10 @@
 import os
-from typing import List
 
 import mpv
 
 import gi
 gi.require_version('Gtk', '3.0')
-from gi.repository import Gio, Gtk, GLib, Gdk, GObject
+from gi.repository import Gdk, Gio, GLib, Gtk
 
 from .ui.main import MainWindow
 from .ui.configure_servers import ConfigureServersDialog
@@ -33,6 +32,8 @@ class LibremsonicApp(Gtk.Application):
             'Specify a configuration file. Defaults to ~/.config/libremsonic/config.json',
             None)
 
+        self.connect('shutdown', lambda _: self.state.save())
+
         self.player = mpv.MPV()
 
         @self.player.property_observer('time-pos')
@@ -118,7 +119,7 @@ class LibremsonicApp(Gtk.Application):
 
         # Load the configuration and update the UI with the curent server, if
         # it exists.
-        self.state.load_config()
+        self.state.load()
 
         # If there is no current server, show the dialog to select a server.
         if self.state.config.current_server is None:
@@ -162,11 +163,11 @@ class LibremsonicApp(Gtk.Application):
 
     def on_server_list_changed(self, action, servers):
         self.state.config.servers = servers
-        self.state.save_config()
+        self.state.save()
 
     def on_connected_server_changed(self, action, current_server):
         self.state.config.current_server = current_server
-        self.state.save_config()
+        self.state.save()
 
         # Reset the CacheManager.
         CacheManager.reset(

libremsonic/config.py

@@ -1,9 +1,6 @@
 import os
 
-from typing import Any, Dict, List
-import json
-
-from libremsonic.from_json import from_json
+from typing import List
 
 
 class ServerConfiguration:
@@ -16,16 +13,17 @@ class ServerConfiguration:
     browse_by_tags: bool
     sync_enabled: bool
 
-    def __init__(self,
-                 name='Default',
-                 server_address='http://yourhost',
-                 local_network_address='',
-                 local_network_ssid='',
-                 username='',
-                 password='',
-                 browse_by_tags=False,
-                 sync_enabled=True):
-
+    def __init__(
+            self,
+            name='Default',
+            server_address='http://yourhost',
+            local_network_address='',
+            local_network_ssid='',
+            username='',
+            password='',
+            browse_by_tags=False,
+            sync_enabled=True,
+    ):
         self.name = name
         self.server_address = server_address
         self.local_network_address = local_network_address
@@ -67,21 +65,3 @@ class AppConfiguration:
             default_cache_location = (os.environ.get('XDG_DATA_HOME')
                                       or os.path.expanduser('~/.local/share'))
             return os.path.join(default_cache_location, 'libremsonic')
-
-
-def get_config(filename: str) -> AppConfiguration:
-    if not os.path.exists(filename):
-        return AppConfiguration.get_default_configuration()
-
-    with open(filename, 'r') as f:
-        try:
-            return from_json(AppConfiguration, json.load(f))
-        except json.decoder.JSONDecodeError:
-            return AppConfiguration.get_default_configuration()
-
-
-def save_config(config: AppConfiguration, filename: str):
-    # Make the necessary directories before writing the config.
-    os.makedirs(os.path.dirname(filename), exist_ok=True)
-    with open(filename, 'w+') as f:
-        f.write(json.dumps(config.to_json(), indent=2, sort_keys=True))

libremsonic/state_manager.py

@@ -1,11 +1,27 @@
-from typing import List, Any
-
-from .config import get_config, save_config, AppConfiguration
+import os
+from pathlib import Path
+import json
+from typing import List
 
+from libremsonic.from_json import from_json
+from .config import AppConfiguration
 from .server.api_objects import Child
 
 
 class ApplicationState:
+    """
+    Represents the state of the application. In general, there are two things
+    that are stored here: configuration, and UI state.
+
+    Configuration is stored in ``config`` which is an ``AppConfiguration``
+    object. UI state is stored as separate properties on this class.
+
+    Configuration is stored to disk in $XDG_CONFIG_HOME/libremsonic. State is
+    stored in $XDG_CACHE_HOME. Nothing in state should be assumed to be
+    permanent. State need not be saved, the ``to_json`` and ``from_json``
+    functions define what part of the state will be saved across application
+    loads.
+    """
     config: AppConfiguration = AppConfiguration.get_default_configuration()
     current_song: Child
     config_file: str
@@ -14,10 +30,51 @@ class ApplicationState:
     volume: int = 100
     old_volume: int = 100
 
-    # TODO save these values that aren't necessarily config to disk
+    def to_json(self):
+        return {
+            'current_song': getattr(self, 'current_song', None),
+            'play_queue': getattr(self, 'play_queue', None),
+            'volume': getattr(self, 'volume', None),
+        }
 
-    def load_config(self):
-        self.config = get_config(self.config_file)
+    def load_from_json(self, json_object):
+        self.current_song = json_object.get('current_song') or None
+        self.play_queue = json_object.get('play_queue') or []
+        self.volume = json_object.get('volume') or 100
 
-    def save_config(self):
-        save_config(self.config, self.config_file)
+    def load(self):
+        self.config = self.get_config(self.config_file)
+
+        if os.path.exists(self.state_filename):
+            with open(self.state_filename, 'r') as f:
+                self.load_from_json(json.load(f))
+
+    def save(self):
+        # Make the necessary directories before writing the config and state.
+        os.makedirs(os.path.dirname(self.config_file), exist_ok=True)
+        os.makedirs(os.path.dirname(self.state_filename), exist_ok=True)
+
+        # Save the config
+        with open(self.config_file, 'w+') as f:
+            f.write(json.dumps(self.config.to_json(), indent=2,
+                               sort_keys=True))
+
+        # Save the state
+        with open(self.state_filename, 'w+') as f:
+            f.write(json.dumps(self.to_json(), indent=2, sort_keys=True))
+
+    def get_config(self, filename: str) -> AppConfiguration:
+        if not os.path.exists(filename):
+            return AppConfiguration.get_default_configuration()
+
+        with open(filename, 'r') as f:
+            try:
+                return from_json(AppConfiguration, json.load(f))
+            except json.decoder.JSONDecodeError:
+                return AppConfiguration.get_default_configuration()
+
+    @property
+    def state_filename(self):
+        state_filename = (os.environ.get('XDG_CACHE_HOME')
+                          or os.path.expanduser('~/.cache'))
+        return os.path.join(state_filename, 'libremsonic/state.yaml')

libremsonic/ui/player_controls.py

@@ -40,7 +40,8 @@ class PlayerControls(Gtk.ActionBar):
         self.play_button.get_child().set_from_icon_name(
             f"media-playback-{icon}-symbolic", Gtk.IconSize.LARGE_TOOLBAR)
 
-        has_current_song = hasattr(state, 'current_song')
+        has_current_song = (hasattr(state, 'current_song')
+                            and state.current_song is not None)
         has_prev_song, has_next_song = False, False
         if has_current_song and state.current_song.id in state.play_queue:
             # TODO will need to change when repeat is implemented
@@ -72,7 +73,7 @@ class PlayerControls(Gtk.ActionBar):
         self.volume_slider.set_value(state.volume)
 
         if not has_current_song:
-            # TODO should probably clear out something?
+            # TODO should probably clear out the cover art display?
             return
 
         self.update_cover_art(state.current_song.coverArt, size='70')