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mcp-nextcloud/nextcloud_mcp_server/vector/document_chunker.py
T
Chris CoutinhoandClaude Opus 4.7 665cb9b1eb refactor: convert f-string logging to lazy %-style format (G004)
Sweep all 1676 G004 violations across 112 files, converting
`logger.<level>(f"…{x}…")` to `logger.<level>("…%s…", x)`.

Why: ruff rule G004 was added to pyproject.toml to enforce lazy
%-style logging — defers formatting until the log level is enabled
and lets structured log tooling match the unformatted template.

Conversion preserves rendered output byte-for-byte:
- `{x}` → `%s` + `x`
- `{x!r}` / `{x!s}` / `{x!a}` → `%r` / `%s` / `%a`
- Format specs (`{x:.2f}`, `{x:>10}`) → `%s` + `format(x, 'spec')`
  (printf-style specs aren't 1:1 with Python format specs, so we
  delegate to `format()` to keep identical output)
- Literal `%` → `%%`
- Concatenated f-strings (`f"a {x} " "b"`) flattened
- Trailing kwargs (`exc_info=True`) preserved

Verified:
- `uv run ruff check --select G004` → 0 violations
- `uv run ty check -- nextcloud_mcp_server` → passes
- `uv run pytest tests/unit/` → 1010 passed

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-13 01:12:17 +02:00

100 lines
3.5 KiB
Python

"""Document chunking for large texts using LangChain text splitters."""
import logging
from dataclasses import dataclass
import anyio
from langchain_text_splitters import RecursiveCharacterTextSplitter
logger = logging.getLogger(__name__)
@dataclass
class ChunkWithPosition:
"""A text chunk with its character position in the original document."""
text: str
start_offset: int # Character position where chunk starts
end_offset: int # Character position where chunk ends (exclusive)
page_number: int | None = None # Page number for PDF chunks (optional)
metadata: dict | None = None # Additional processor-specific metadata (optional)
class DocumentChunker:
"""Chunk large documents for optimal embedding using LangChain text splitters.
Uses RecursiveCharacterTextSplitter which preserves semantic boundaries
by splitting on sentence and paragraph boundaries before resorting to
character-level splitting.
"""
def __init__(self, chunk_size: int = 2048, overlap: int = 200):
"""
Initialize document chunker.
Args:
chunk_size: Number of characters per chunk (default: 2048)
overlap: Number of overlapping characters between chunks (default: 200)
"""
self.chunk_size = chunk_size
self.overlap = overlap
# Initialize LangChain RecursiveCharacterTextSplitter
# Uses hierarchical splitting to preserve semantic boundaries:
# - Paragraphs (\n\n)
# - Sentences (. ! ?)
# - Words (spaces)
# - Characters (last resort)
# This prevents mid-sentence splitting while maintaining semantic coherence
self.splitter = RecursiveCharacterTextSplitter(
chunk_size=chunk_size,
chunk_overlap=overlap,
add_start_index=True, # Enable position tracking
strip_whitespace=True,
)
async def chunk_text(self, content: str) -> list[ChunkWithPosition]:
"""
Split text into overlapping chunks with position tracking.
Uses LangChain's RecursiveCharacterTextSplitter to create chunks that
preserve semantic boundaries by splitting at paragraphs and sentences
before resorting to word or character-level splitting. This ensures
sentences are kept intact. Preserves character positions for each chunk
to enable precise document retrieval.
Args:
content: Text content to chunk
Returns:
List of chunks with their character positions in the original content
"""
# Handle empty content - return single empty chunk for backward compatibility
if not content:
return [ChunkWithPosition(text="", start_offset=0, end_offset=0)]
# Run CPU-bound text splitting in thread pool to avoid blocking event loop
docs = await anyio.to_thread.run_sync( # type: ignore[attr-defined]
self.splitter.create_documents,
[content],
)
# Convert LangChain Documents to ChunkWithPosition objects
chunks = [
ChunkWithPosition(
text=doc.page_content,
start_offset=doc.metadata.get("start_index", 0),
end_offset=doc.metadata.get("start_index", 0) + len(doc.page_content),
)
for doc in docs
]
logger.debug(
"Chunked document into %s chunks (chunk_size=%s, overlap=%s)",
len(chunks),
self.chunk_size,
self.overlap,
)
return chunks