metadata writer: some progress

.env.template

@@ -1,3 +1,5 @@
 LLM_API_BASE_URL = "http://localhost:1234/v1"
 LLM_API_KEY = "not-relevant"
 LLM_DEFAULT_TEMPERATURE = 1.0
+
+METADATA_PREFIX = "photools:"

src/photools3/llm_session.py

@@ -17,12 +17,10 @@ from photools3.models import (
     LlmResponseQuality,
 )
 from photools3.photo import Photo
-from photools3.settings import Settings
+from photools3.settings import settings
 
 logger = logging.getLogger(__name__)
 
-settings = Settings()  # type: ignore[reportCallIssue]
-
 
 class LlmSession:
     base_url: str = str(settings.llm_api_base_url)

src/photools3/metadata_writer.py

@@ -1,15 +1,48 @@
 import logging
 from pathlib import Path
+from typing import Annotated, Any
+
+import exiftool
+from pydantic import StringConstraints
+
+from photools3.settings import settings
 
 log = logging.getLogger(__name__)
 
 # File extensions that should use XMP sidecars
 SIDECAR_EXTENSIONS = {".dng", ".nef", ".cr2", ".cr3", ".arw", ".raf", ".orf", ".rw2"}
 
+XmpKey = Annotated[str, StringConstraints(pattern=r"^\w+\:\w+")]
 
 type Caption = str | None
 type Keywords = list[str] | None
 type Color = str | None
+type XmpMetadata = dict[str, Any]
+
+XMO_KEYS_CAPTION: list[XmpKey] = [
+    "EXIF:ImageDescription",
+    "XMP:Description",
+    "IPTC:Caption-Abstract",
+]
+
+XMP_KEYS_TAG: list[XmpKey] = [
+    "XMP:HierarchicalSubject",
+    "XMP:Subject",
+    "IPTC:Keywords",
+]
+
+
+def _prefixed(txt: str) -> str:
+    return f"{settings.metadata_prefix} {txt}"
+
+
+def read_metadata(path: Path) -> XmpMetadata | None:
+    try:
+        with exiftool.ExifToolHelper() as exif:
+            return exif.get_metadata([str(path)])[0]
+    except Exception as exc:  # noqa: BLE001
+        log.error(f"Could not read metadata from {path}: {exc}")
+
 
 
 class MetadataWriter:

src/photools3/settings.py

@@ -18,3 +18,8 @@ class Settings(BaseSettings):
     llm_api_base_url: Url
     llm_api_key: str
     llm_default_temperature: float
+
+    metadata_prefix: str
+
+
+settings = Settings()  # type: ignore[reportCallIssue]

test/test_metadata_writer.py

@@ -0,0 +1,8 @@
+
+from photools3.metadata_writer import read_metadata
+from test.test_photo import PATHS_DNG_EXAMPLES
+
+
+def test_read_metadata():
+    result = read_metadata(PATHS_DNG_EXAMPLES[0])
+    assert result