Add auto save and restore for config options

Author: bulletmark

README.rst

@@ -59,7 +59,7 @@ The help menu shows basic command-line options.
 
     $ ptpython --help
     usage: ptpython [-h] [--vi] [-i] [--light-bg] [--dark-bg] [--config-file CONFIG_FILE]
-                    [--history-file HISTORY_FILE] [-V]
+                    [--options-dir OPTIONS_DIR] [--history-file HISTORY_FILE] [-V]
                     [args ...]
 
     ptpython: Interactive Python shell.
@@ -75,6 +75,9 @@ The help menu shows basic command-line options.
       --dark-bg             Run on a dark background (use light colors for text).
       --config-file CONFIG_FILE
                             Location of configuration file.
+      --options-dir OPTIONS_DIR
+                            Directory to store options save file.
+                            Specify "none" to disable option storing.
       --history-file HISTORY_FILE
                             Location of history file.
       -V, --version         show program's version number and exit
@@ -143,8 +146,9 @@ like this:
    else:
        sys.exit(embed(globals(), locals()))
 
-Note config file support currently only works when invoking `ptpython` directly.
-That it, the config file will be ignored when embedding ptpython in an application.
+Note config file and option storage support currently only works when invoking
+`ptpython` directly. That is, the config file will be ignored when embedding
+ptpython in an application and option changes will not be saved.
 
 Multiline editing
 *****************

ptpython/entry_points/run_ptipython.py

@@ -4,13 +4,14 @@
 import os
 import sys
 
-from .run_ptpython import create_parser, get_config_and_history_file
+from .run_ptpython import create_parser, get_config_and_history_file, get_options_file
 
 
 def run(user_ns=None):
     a = create_parser().parse_args()
 
     config_file, history_file = get_config_and_history_file(a)
+    options_file = get_options_file(a, "ipython-config")
 
     # If IPython is not available, show message and exit here with error status
     # code.
@@ -72,6 +73,7 @@ def configure(repl):
         embed(
             vi_mode=a.vi,
             history_filename=history_file,
+            options_filename=options_file,
             configure=configure,
             user_ns=user_ns,
             title="IPython REPL (ptipython)",

ptpython/entry_points/run_ptpython.py

@@ -13,6 +13,9 @@
   --dark-bg             Run on a dark background (use light colors for text).
   --config-file CONFIG_FILE
                         Location of configuration file.
+  --options-dir OPTIONS_DIR
+                        Directory to store options save file.
+                        Specify "none" to disable option storing.
   --history-file HISTORY_FILE
                         Location of history file.
   -V, --version         show program's version number and exit
@@ -25,8 +28,8 @@
 
 import argparse
 import os
-import pathlib
 import sys
+from pathlib import Path
 from textwrap import dedent
 from typing import IO, Optional, Tuple
 
@@ -81,6 +84,10 @@ def create_parser() -> _Parser:
     parser.add_argument(
         "--config-file", type=str, help="Location of configuration file."
     )
+    parser.add_argument(
+        "--options-dir", type=str, help="Directory to store options save file. "
+        "Specify \"none\" to disable option storing."
+    )
     parser.add_argument("--history-file", type=str, help="Location of history file.")
     parser.add_argument(
         "-V",
@@ -105,7 +112,7 @@ def get_config_and_history_file(namespace: argparse.Namespace) -> tuple[str, str
 
     # Create directories.
     for d in (config_dir, data_dir):
-        pathlib.Path(d).mkdir(parents=True, exist_ok=True)
+        Path(d).mkdir(parents=True, exist_ok=True)
 
     # Determine config file to be used.
     config_file = os.path.join(config_dir, "config.py")
@@ -155,10 +162,26 @@ def get_config_and_history_file(namespace: argparse.Namespace) -> tuple[str, str
     return config_file, history_file
 
 
+def get_options_file(namespace: argparse.Namespace, filename: str) -> str | None:
+    """
+    Given the options storage file name, add the directory path.
+    """
+    if namespace.options_dir:
+        if namespace.options_dir.lower() in {"none", "nil"}:
+            return None
+        return str(Path(namespace.options_dir, filename))
+
+    cnfdir = Path(os.getenv("PTPYTHON_CONFIG_HOME",
+                            appdirs.user_config_dir("ptpython", "prompt_toolkit")))
+
+    return str(cnfdir / filename)
+
+
 def run() -> None:
     a = create_parser().parse_args()
 
     config_file, history_file = get_config_and_history_file(a)
+    options_file = get_options_file(a, "config")
 
     # Startup path
     startup_paths = []
@@ -209,6 +232,7 @@ def configure(repl: PythonRepl) -> None:
         embed(
             vi_mode=a.vi,
             history_filename=history_file,
+            options_filename=options_file,
             configure=configure,
             locals=__main__.__dict__,
             globals=__main__.__dict__,

ptpython/ipython.py

@@ -40,6 +40,7 @@
 from .python_input import PythonInput
 from .style import default_ui_style
 from .validator import PythonValidator
+from . import options_saver
 
 __all__ = ["embed"]
 
@@ -223,6 +224,7 @@ class InteractiveShellEmbed(_InteractiveShellEmbed):
     def __init__(self, *a, **kw):
         vi_mode = kw.pop("vi_mode", False)
         history_filename = kw.pop("history_filename", None)
+        options_filename = kw.pop("options_filename", None)
         configure = kw.pop("configure", None)
         title = kw.pop("title", None)
 
@@ -248,6 +250,9 @@ def get_globals():
             configure(python_input)
             python_input.prompt_style = "ipython"  # Don't take from config.
 
+        if options_filename:
+            options_saver.create(python_input, options_filename)
+
         self.python_input = python_input
 
     def prompt_for_code(self) -> str:

ptpython/options_saver.py

@@ -0,0 +1,123 @@
+"""
+Restores options on startup and saves changed options on termination.
+"""
+from __future__ import annotations
+
+import sys
+import json
+import atexit
+from pathlib import Path
+from functools import partial
+from enum import Enum
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from python_input import PythonInput
+
+
+class OptionsSaver:
+    "Manages options saving and restoring"
+    def __init__(self, repl: "PythonInput", filename: str) -> None:
+        "Instance created at program startup"
+        self.repl = repl
+
+        # Add suffix if given file does not have one
+        self.file = Path(filename)
+        if not self.file.suffix:
+            self.file = self.file.with_suffix(".json")
+
+        self.file_bad = False
+
+        # Read all stored options from file. Skip and report at
+        # termination if the file is corrupt/unreadable.
+        self.stored = {}
+        if self.file.exists():
+            try:
+                with self.file.open() as fp:
+                    self.stored = json.load(fp)
+            except Exception:
+                self.file_bad = True
+
+        # Iterate over all options and save record of defaults and also
+        # activate any saved options
+        self.defaults = {}
+        for category in self.repl.options:
+            for option in category.options:
+                field = option.field_name
+                def_val, val_type = self.get_option(field)
+                self.defaults[field] = def_val
+                val = self.stored.get(field)
+                if val is not None and val != def_val:
+
+                    # Handle special case to convert enums from int
+                    if issubclass(val_type, Enum):
+                        val = list(val_type)[val]
+
+                    # Handle special cases where a function must be
+                    # called to store and enact change
+                    funcs = option.get_values()
+                    if isinstance(list(funcs.values())[0], partial):
+                        if val_type is float:
+                            val = f"{val:.2f}"
+                        funcs[val]()
+                    else:
+                        setattr(self.repl, field, val)
+
+        # Save changes at program exit
+        atexit.register(self.save)
+
+    def get_option(self, field: str) -> tuple[object, type]:
+        "Returns option value and type for specified field"
+        val = getattr(self.repl, field)
+        val_type = type(val)
+
+        # Handle special case to convert enums to int
+        if issubclass(val_type, Enum):
+            val = list(val_type).index(val)
+
+        # Floats should be rounded to 2 decimal places
+        if isinstance(val, float):
+            val = round(val, 2)
+
+        return val, val_type
+
+    def save(self) -> None:
+        "Save changed options to file (called once at termination)"
+        # Ignore if abnormal (i.e. within exception) termination
+        if sys.exc_info()[0]:
+            return
+
+        new = {}
+        for category in self.repl.options:
+            for option in category.options:
+                field = option.field_name
+                val, _ = self.get_option(field)
+                if val != self.defaults[field]:
+                    new[field] = val
+
+        # Save if file will change. We only save options which are
+        # different to the defaults and we always prune all other
+        # options.
+        if new != self.stored and not self.file_bad:
+            if new:
+                try:
+                    self.file.parent.mkdir(parents=True, exist_ok=True)
+                    with self.file.open("w") as fp:
+                        json.dump(new, fp, indent=2)
+                except Exception:
+                    self.file_bad = True
+
+            elif self.file.exists():
+                try:
+                    self.file.unlink()
+                except Exception:
+                    self.file_bad = True
+
+        if self.file_bad:
+            print(f"Failed to read/write file: {self.file}", file=sys.stderr)
+
+def create(repl: "PythonInput", filename: str) -> None:
+    'Create/activate the options saver'
+    # Note, no need to save the instance because it is kept alive by
+    # reference from atexit()
+    OptionsSaver(repl, filename)