feat: static username extractor

Reads the username from a static declaration in the mapping file.

Author: DCPRevere

README.md

@@ -284,6 +284,21 @@ For instance, if a regular [pass] call would be `pass show dev/github.com/langui
 
 No configuration options.
 
+#### Strategy "static"
+
+Allows defining the username in the mapping file using the `username` key.
+
+Example:
+
+```ini
+[DEFAULT]
+username_extractor=static
+username = myuser
+
+[example.com]
+username = myexampleusername
+```
+
 ### File Encoding
 
 By default, password store entries are assumed to use UTF-8 encoding.

passgithelper.py

@@ -306,13 +306,31 @@ def get_value(
         return os.path.split(entry_name)[1]
 
 
+class StaticUsernameExtractor(DataExtractor):
+    """Extract username from a static field in the mapping configuration."""
+
+    def __init__(self) -> None:
+        self._username: str | None = None
+
+    def configure(self, config: configparser.SectionProxy) -> None:
+        """Store the username from the mapping configuration."""
+        self._username = config.get("username")
+
+    def get_value(
+        self, entry_name: Text, entry_lines: Sequence[Text]  # noqa: ARG002
+    ) -> Optional[Text]:
+        """Return the stored username."""
+        return self._username
+
+
 _line_extractor_name = "specific_line"
 _username_extractors = {
     _line_extractor_name: SpecificLineExtractor(1, 0, option_suffix="_username"),
     "regex_search": RegexSearchExtractor(
         r"^username: +(.*)$", option_suffix="_username"
     ),
     "entry_name": EntryNameExtractor(option_suffix="_username"),
+    "static": StaticUsernameExtractor(),
 }
 _password_extractors = {
     _line_extractor_name: SpecificLineExtractor(0, 0, option_suffix="_password"),

test_passgithelper.py

@@ -137,6 +137,73 @@ def test_smoke(self) -> None:
         assert passgithelper.EntryNameExtractor().get_value("foo/bar", []) == "bar"
 
 
+class TestStaticUsernameExtractor:
+    def test_extracts_username_from_config(self) -> None:
+        config = configparser.ConfigParser()
+        config.read_string(
+            """[test]
+username = [email protected]
+"""
+        )
+
+        extractor = passgithelper.StaticUsernameExtractor()
+        extractor.configure(config["test"])
+
+        assert (
+            extractor.get_value("any/entry", ["any", "lines"]) == "[email protected]"
+        )
+
+    def test_returns_none_when_no_username_configured(self) -> None:
+        config = configparser.ConfigParser()
+        config.read_string(
+            """[test]
+target = some/target
+"""
+        )
+
+        extractor = passgithelper.StaticUsernameExtractor()
+        extractor.configure(config["test"])
+
+        assert extractor.get_value("any/entry", ["any", "lines"]) is None
+
+    def test_inherits_from_default_section(self) -> None:
+        config = configparser.ConfigParser()
+        config.read_string(
+            """[DEFAULT]
+username = [email protected]
+
+[test]
+target = some/target
+"""
+        )
+
+        extractor = passgithelper.StaticUsernameExtractor()
+        extractor.configure(config["test"])
+
+        assert (
+            extractor.get_value("any/entry", ["any", "lines"]) == "[email protected]"
+        )
+
+    def test_section_overrides_default(self) -> None:
+        config = configparser.ConfigParser()
+        config.read_string(
+            """[DEFAULT]
+username = [email protected]
+
+[test]
+target = some/target
+username = [email protected]
+"""
+        )
+
+        extractor = passgithelper.StaticUsernameExtractor()
+        extractor.configure(config["test"])
+
+        assert (
+            extractor.get_value("any/entry", ["any", "lines"]) == "[email protected]"
+        )
+
+
 @pytest.mark.parametrize(
     "helper_config",
     [