feat(api): support file uploads via JSON base64 and multipart/form-data

nanobot/utils/document.py

@@ -0,0 +1,206 @@
+"""Document text extraction utilities for nanobot."""
+
+from pathlib import Path
+
+from loguru import logger
+
+try:
+    from pypdf import PdfReader
+except ImportError:
+    PdfReader = None  # type: ignore
+
+try:
+    from docx import Document as DocxDocument
+except ImportError:
+    DocxDocument = None  # type: ignore
+
+try:
+    from openpyxl import load_workbook
+except ImportError:
+    load_workbook = None  # type: ignore
+
+try:
+    from pptx import Presentation as PptxPresentation
+except ImportError:
+    PptxPresentation = None  # type: ignore
+
+
+# Supported file extensions for text extraction
+SUPPORTED_EXTENSIONS: set[str] = {
+    # Document formats
+    ".pdf",
+    ".docx",
+    ".xlsx",
+    ".pptx",
+    # Text formats
+    ".txt",
+    ".md",
+    ".csv",
+    ".json",
+    ".xml",
+    ".html",
+    ".htm",
+    ".log",
+    ".yaml",
+    ".yml",
+    ".toml",
+    ".ini",
+    ".cfg",
+    # Image formats (for future OCR support)
+    ".png",
+    ".jpg",
+    ".jpeg",
+    ".gif",
+    ".webp",
+}
+
+_MAX_TEXT_LENGTH = 200_000
+
+
+def extract_text(path: Path) -> str | None:
+    """Extract text from a file.
+
+    Args:
+        path: Path to the file.
+
+    Returns:
+        Extracted text as string, None for unsupported types,
+        or error string for failures.
+    """
+    if not isinstance(path, Path):
+        path = Path(path)
+
+    if not path.exists():
+        return f"[error: file not found: {path}]"
+
+    ext = path.suffix.lower()
+
+    # Document formats
+    if ext == ".pdf":
+        if PdfReader is None:
+            return "[error: pypdf not installed]"
+        return _extract_pdf(path)
+    elif ext == ".docx":
+        if DocxDocument is None:
+            return "[error: python-docx not installed]"
+        return _extract_docx(path)
+    elif ext == ".xlsx":
+        if load_workbook is None:
+            return "[error: openpyxl not installed]"
+        return _extract_xlsx(path)
+    elif ext == ".pptx":
+        if PptxPresentation is None:
+            return "[error: python-pptx not installed]"
+        return _extract_pptx(path)
+    elif _is_text_extension(ext):
+        return _extract_text_file(path)
+    elif ext in {".png", ".jpg", ".jpeg", ".gif", ".webp"}:
+        # Image files - for future OCR support
+        return f"[image: {path.name}]"
+    else:
+        # Unsupported extension
+        return None
+
+
+def _extract_pdf(path: Path) -> str:
+    """Extract text from PDF using pypdf."""
+    try:
+        reader = PdfReader(path)
+        pages: list[str] = []
+        for i, page in enumerate(reader.pages, 1):
+            text = page.extract_text() or ""
+            pages.append(f"--- Page {i} ---\n{text}")
+        return _truncate("\n\n".join(pages), _MAX_TEXT_LENGTH)
+    except Exception as e:
+        logger.error("Failed to extract PDF {}: {}", path, e)
+        return f"[error: failed to extract PDF: {e!s}]"
+
+
+def _extract_docx(path: Path) -> str:
+    """Extract text from DOCX using python-docx."""
+    try:
+        doc = DocxDocument(path)
+        paragraphs: list[str] = [p.text for p in doc.paragraphs if p.text.strip()]
+        return _truncate("\n\n".join(paragraphs), _MAX_TEXT_LENGTH)
+    except Exception as e:
+        logger.error("Failed to extract DOCX {}: {}", path, e)
+        return f"[error: failed to extract DOCX: {e!s}]"
+
+
+def _extract_xlsx(path: Path) -> str:
+    """Extract text from XLSX using openpyxl."""
+    try:
+        wb = load_workbook(path, read_only=True, data_only=True)
+        sheets: list[str] = []
+        for sheet_name in wb.sheetnames:
+            ws = wb[sheet_name]
+            rows: list[str] = []
+            for row in ws.iter_rows(values_only=True):
+                row_text = "\t".join(str(cell) if cell is not None else "" for cell in row)
+                if row_text.strip():
+                    rows.append(row_text)
+            if rows:
+                sheets.append(f"--- Sheet: {sheet_name} ---\n" + "\n".join(rows))
+        wb.close()
+        return _truncate("\n\n".join(sheets), _MAX_TEXT_LENGTH)
+    except Exception as e:
+        logger.error("Failed to extract XLSX {}: {}", path, e)
+        return f"[error: failed to extract XLSX: {e!s}]"
+
+
+def _extract_pptx(path: Path) -> str:
+    """Extract text from PPTX using python-pptx."""
+    try:
+        prs = PptxPresentation(path)
+        slides: list[str] = []
+        for i, slide in enumerate(prs.slides, 1):
+            slide_text: list[str] = []
+            for shape in slide.shapes:
+                if hasattr(shape, "text") and shape.text:
+                    slide_text.append(shape.text)
+            if slide_text:
+                slides.append(f"--- Slide {i} ---\n" + "\n".join(slide_text))
+        return _truncate("\n\n".join(slides), _MAX_TEXT_LENGTH)
+    except Exception as e:
+        logger.error("Failed to extract PPTX {}: {}", path, e)
+        return f"[error: failed to extract PPTX: {e!s}]"
+
+
+def _extract_text_file(path: Path) -> str:
+    """Extract text from a plain text file."""
+    try:
+        # Try UTF-8 first, then latin-1 fallback
+        try:
+            content = path.read_text(encoding="utf-8")
+        except UnicodeDecodeError:
+            content = path.read_text(encoding="latin-1")
+        return _truncate(content, _MAX_TEXT_LENGTH)
+    except Exception as e:
+        logger.error("Failed to read text file {}: {}", path, e)
+        return f"[error: failed to read file: {e!s}]"
+
+
+def _truncate(text: str, max_length: int) -> str:
+    """Truncate text with a suffix indicating truncation."""
+    if len(text) <= max_length:
+        return text
+    return text[:max_length] + f"... (truncated, {len(text)} chars total)"
+
+
+def _is_text_extension(ext: str) -> bool:
+    """Check if extension is a text format."""
+    return ext in {
+        ".txt",
+        ".md",
+        ".csv",
+        ".json",
+        ".xml",
+        ".html",
+        ".htm",
+        ".log",
+        ".yaml",
+        ".yml",
+        ".toml",
+        ".ini",
+        ".cfg",
+    }