Use file streams instead of file paths

Using a file stream for the config parsers means we can separate
concerns more and have the parsers only responsible for parsing a file
stream, as opposed to opening and file and then parsing it.

Author: dbatten5

src/maison/config_parser.py

@@ -13,14 +13,14 @@
 class Parser(typing.Protocol):
     """Defines the interface for a `Parser` class that's used to parse a config."""
 
-    def parse_config(self, file_path: pathlib.Path) -> typedefs.ConfigValues:
-        """Parse a config file.
+    def parse_config(self, file: typing.BinaryIO) -> typedefs.ConfigValues:
+        """Parse a config.
 
         Args:
-            file_path: the path to the config file
+            file: the binary stream of the config file
 
         Returns:
-            the config values
+            the parsed config
         """
         ...
 
@@ -42,18 +42,22 @@ def register_parser(
         key = (suffix, stem)
         self._parsers[key] = parser
 
-    def parse_config(self, file_path: pathlib.Path) -> typedefs.ConfigValues:
+    def parse_config(
+        self,
+        file_path: pathlib.Path,
+        file: typing.BinaryIO,
+    ) -> typedefs.ConfigValues:
         """See `Parser.parse_config`."""
         key: ParserDictKey
 
         # First try (suffix, stem)
         key = (file_path.suffix, file_path.stem)
         if key in self._parsers:
-            return self._parsers[key].parse_config(file_path)
+            return self._parsers[key].parse_config(file)
 
         # Then fallback to (suffix, None)
         key = (file_path.suffix, None)
         if key in self._parsers:
-            return self._parsers[key].parse_config(file_path)
+            return self._parsers[key].parse_config(file)
 
         raise errors.UnsupportedConfigError(f"No parser registered for {file_path}")

src/maison/parsers/ini.py

@@ -1,7 +1,8 @@
 """A parser for .ini files."""
 
 import configparser
-import pathlib
+import io
+import typing
 
 from maison import typedefs
 
@@ -12,8 +13,12 @@ class IniParser:
     Implements the `Parser` protocol
     """
 
-    def parse_config(self, file_path: pathlib.Path) -> typedefs.ConfigValues:
+    def parse_config(self, file: typing.BinaryIO) -> typedefs.ConfigValues:
         """See the Parser.parse_config method."""
         config = configparser.ConfigParser()
-        _ = config.read(file_path)
+        text_io = io.TextIOWrapper(file, encoding="utf-8")
+        try:
+            config.read_file(text_io)
+        except UnicodeDecodeError:
+            return {}
         return {section: dict(config.items(section)) for section in config.sections()}

src/maison/parsers/toml.py

@@ -1,6 +1,5 @@
 """A parser for .toml files."""
 
-import pathlib
 import sys
 
 
@@ -36,11 +35,10 @@ def __init__(self, section_key: typing.Optional[tuple[str, ...]] = None) -> None
         """
         self.section_key = section_key or ()
 
-    def parse_config(self, file_path: pathlib.Path) -> typedefs.ConfigValues:
+    def parse_config(self, file: typing.BinaryIO) -> typedefs.ConfigValues:
         """See the Parser.parse_config method."""
         try:
-            with file_path.open(mode="rb") as fd:
-                values = dict(tomllib.load(fd))
+            values = dict(tomllib.load(file))
         except (FileNotFoundError, tomllib.TOMLDecodeError):
             return {}
 

src/maison/protocols.py

@@ -61,11 +61,16 @@ def open_file(self, path: pathlib.Path) -> typing.BinaryIO:
 class ConfigParser(typing.Protocol):
     """Defines the interface for a class that parses a config."""
 
-    def parse_config(self, file_path: pathlib.Path) -> typedefs.ConfigValues:
+    def parse_config(
+        self,
+        file_path: pathlib.Path,
+        file: typing.BinaryIO,
+    ) -> typedefs.ConfigValues:
         """Parse a config.
 
         Args:
             file_path: the path to a config file.
+            file: the binary I/O stream of the file.
 
         Returns:
             the parsed config

src/maison/service.py

@@ -67,7 +67,8 @@ def get_config_values(
         config_values: typedefs.ConfigValues = {}
 
         for path in config_file_paths:
-            parsed_config = self.config_parser.parse_config(path)
+            file = self.filesystem.open_file(path=path)
+            parsed_config = self.config_parser.parse_config(file_path=path, file=file)
             config_values = utils.deep_merge(config_values, parsed_config)
 
             if not merge_configs: