Set config directory according to runtime platform

This commit changes the definition of the persistent state and
configuration files (`SOCO_CLI_DIR`) to derive from the output of
[platform.system()][1], rather than being fixed to an eponymous,
dot-prefixed directory in the top level of the user's `$HOME`.

Furthermore, on POSIX-compliant platforms it tests for the
presence of the XDG_CONFIG_HOME environment variable and
establishes the config directory there, with a fallback to the
`$HOME/.config` directory as defined in the [XDG Base Directory Specification][2].

On Microsoft Windows® systems, it places the directory inside
the path defined by the `%LOCALAPPDATA%` environment
variable, which is the vendor-specified path for all machine-
specific application data belonging to the active user.

On all other platforms the former behavior is retained. Several
individual definitions of this path were consolidated into the
`SOCO_CLI_DIR` constant already present in the file, which itself was relocated along with the attendant `_confirm_soco_cli_dir` method earlier in the file, nearer to the other defined constants.

1: https://docs.python.org/3/library/platform.html#platform.system
2: https://specifications.freedesktop.org/basedir-spec/latest/index.html

Author: jlmello57

soco_cli/utils.py

@@ -10,9 +10,9 @@
     import readline
 except ImportError:
     pass
+import platform
 import sys
 from collections.abc import Sequence
-from platform import python_version
 from time import sleep
 
 import soco  # type: ignore
@@ -35,6 +35,28 @@ def event_unsubscribe(sub):
     logging.info("Unsubscribed")
 
 
+if platform.system() == "Linux":
+    if "XDG_CONFIG_HOME" in os.environ:
+        SOCO_CLI_DIR = os.path.join(os.path.expandvars("${XDG_CONFIG_HOME}"), "soco-cli")
+    else:
+        SOCO_CLI_DIR = os.path.join(os.path.expandvars("~user"), ".config", "soco-cli")
+elif platform.system() == "Windows":
+    SOCO_CLI_DIR = os.path.join(os.path.expandvars("%LOCALAPPDATA%"), "soco-cli")
+else:
+    SOCO_CLI_DIR = os.path.join(os.path.expanduser("~user"), ".soco-cli")
+
+
+def _confirm_soco_cli_dir() -> bool:
+    if not os.path.exists(SOCO_CLI_DIR):
+        logging.info("Creating directory '{}'".format(SOCO_CLI_DIR))
+        try:
+            os.mkdir(SOCO_CLI_DIR)
+            return True
+        except:
+            error_report("Failed to create directory '{}'".format(SOCO_CLI_DIR))
+            return False
+
+
 INTERACTIVE = False
 API = False
 SINGLE_KEYSTROKE = False
@@ -226,7 +248,7 @@ def convert_true_false(true_or_false, conversion="YesOrNo"):
 def version():
     print("soco-cli version:   {}".format(__version__), flush=True)
     print("soco version:       {}".format(soco.__version__), flush=True)
-    print("python version:     {}".format(python_version()), flush=True)
+    print("python version:     {}".format(platform.python_version()), flush=True)
     print("command path:       {}".format(sys.argv[0]), flush=True)
 
 
@@ -712,38 +734,38 @@ def check_args(args):
     return message
 
 
-path = os.path.expanduser("~") + "/.soco-cli/"
-filename = "saved_search.pickle"
-pathname = path + filename
+search_pathname = os.path.join(SOCO_CLI_DIR, "saved_search.pickle")
 
 
 def save_search(result):
-    if not os.path.exists(path):
-        os.mkdir(path)
-    with open(pathname, "wb") as f:
-        pickle.dump(result, f)
-    logging.info("Saved search results at {}".format(pathname))
+    if not _confirm_soco_cli_dir():
+        return
+    try:
+        with open(search_pathname, "wb") as f:
+            pickle.dump(result, f)
+        logging.info("Saved search results at {}".format(search_pathname))
+    except Exception as e:
+        logging.info("Error saving speaker search results: {}".format(e))
     return True
 
 
 def read_search():
-    if os.path.exists(pathname):
-        logging.info("Loading search results from {}".format(pathname))
+    if os.path.exists(search_pathname):
+        logging.info("Loading search results from {}".format(search_pathname))
         try:
-            with open(pathname, "rb") as f:
+            with open(search_pathname, "rb") as f:
                 return pickle.load(f)
         except Exception as e:
             logging.info("Failed to load search results: %s", e)
     return None
 
 
-filename = "queue_insertion_position.pickle"
-queue_pathname = path + filename
+queue_pathname = os.path.join(SOCO_CLI_DIR, "queue_insertion_position.pickle")
 
 
 def save_queue_insertion_position(queue_position: int):
-    if not os.path.exists(path):
-        os.mkdir(path)
+    if not _confirm_soco_cli_dir:
+        return
     with open(queue_pathname, "wb") as f:
         pickle.dump(queue_position, f)
     logging.info("Saved queue position at {}".format(queue_pathname))
@@ -765,7 +787,6 @@ def get_queue_insertion_position() -> int:
 
 
 # Interactive shell history file
-SOCO_CLI_DIR = os.path.join(os.path.expanduser("~"), ".soco-cli")
 HIST_FILE = os.path.join(SOCO_CLI_DIR, "shell-history.txt")
 HIST_LEN = 50
 
@@ -846,17 +867,6 @@ def playback_state(state):
 SUBS_LIST = set()
 
 
-def _confirm_soco_cli_dir() -> bool:
-    if not os.path.exists(SOCO_CLI_DIR):
-        logging.info("Creating directory '{}'".format(SOCO_CLI_DIR))
-        try:
-            os.mkdir(SOCO_CLI_DIR)
-            return True
-        except:
-            error_report("Failed to create directory '{}'".format(SOCO_CLI_DIR))
-            return False
-
-
 def remember_event_sub(sub):
     global SUBS_LIST
     logging.info("Adding event subscription record: '{}'".format(sub))