Merge pull request #34 from bcye/feature/csv-handler

Add CSV Handler

src/output_handlers/csv.py

@@ -0,0 +1,77 @@
+"""CSV output handler for writing entries to a single CSV file with ID and title."""
+from pathlib import Path
+import aiofiles
+from .base_handler import BaseHandler
+
+
+class CsvHandler(BaseHandler):
+    """
+    Handler for writing entries to a single CSV file.
+    This handler extracts only the ID and title (from properties.title)
+    rather than writing the entire JSON document.
+    """
+
+    file_writer: object # I believe aiofiles doesn't expose a type for this
+
+    @classmethod
+    async def create(
+        cls,
+        output_path: Path,
+        **kwargs,
+    ) -> "CsvHandler":
+        """
+        Initializes the CSVHandler.
+
+        Args:
+            output_path (Path): Path to the CSV file to write to.
+            **kwargs: Additional keyword arguments.
+        """
+        obj = await super().create(**kwargs)
+        output_path = Path(output_path)
+
+        # Create the containing directory if it doesn't exist
+        output_path.parent.mkdir(parents=True, exist_ok=True)
+
+        # Create file with header if it doesn't exist
+        if not output_path.exists():
+            async with aiofiles.open(output_path, mode='w', encoding='utf-8') as file:
+                await file.write('"id","title"\n')
+
+        # open the file and keep it open for appending
+        obj.file_writer = await aiofiles.open(output_path, mode='a', encoding='utf-8')
+
+        return obj
+
+
+    async def _write_entry(self, entry: dict, uid: str) -> bool:
+        """
+        Asynchronously writes a single entry to the CSV file.
+
+        Args:
+            entry (dict): The entry to write.
+            uid (str): The unique identifier for the entry.
+
+        Returns:
+            bool: True if the entry was written successfully, False otherwise.
+        """
+        try:
+            # Extract title from properties.title
+            title = entry.get("properties", {}).get("title", "")
+
+            # Escape quotes in title
+            title = str(title).replace('"', '""')
+
+            await self.file_writer.write(f'"{uid}","{title}"\n')
+
+            return True
+        except Exception:
+            self.logger.exception(f"Error writing entry {uid} to CSV.")
+            return False
+
+
+    async def close(self):
+        """
+        Performs cleanup and logs statistics.
+        """
+        await self.file_writer.close()
+        await super().close()