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"""
PDF Processor
-------------
Purpose: Process PDF files and extract text.
"""
import os
from pathlib import Path
from typing import List, Dict, Tuple
import logging
import PyPDF2
logger = logging.getLogger(__name__)
@staticmethod
def extract_text_pypdf2(pdf_path: str) -> Tuple[str, Dict]:
"""
Extract text from PDF using PyPDF2.
Args:
pdf_path: Path to PDF file
Returns:
Tuple of (text, metadata)
metadata includes: num_pages, title, author (if available)
Note: PyPDF2 works okay for text-based PDFs.
For scanned PDFs, consider using OCR tools.
"""
try:
with open(pdf_path, 'rb') as pdf_file:
pdf_reader = PyPDF2.PdfReader(pdf_file)
# Extract metadata
metadata = pdf_reader.metadata or {}
num_pages = len(pdf_reader.pages)
# Extract text from all pages
text = ""
page_texts = {}
for page_num, page in enumerate(pdf_reader.pages):
page_text = page.extract_text()
text += f"\n--- Page {page_num + 1} ---\n{page_text}\n"
page_texts[page_num + 1] = page_text
result_metadata = {
"num_pages": num_pages,
"title": metadata.get('/Title', 'Unknown'),
"author": metadata.get('/Author', 'Unknown'),
"page_texts": page_texts,
"source_file": os.path.basename(pdf_path)
}
return text, result_metadata
except Exception as e:
logger.error(f"Failed to extract text from {pdf_path}: {e}")
raise
def extract_text_pdfplumber(pdf_path: str) -> Tuple[str, Dict]:
"""
Extract text from PDF using pdfplumber (better quality).
Args:
pdf_path: Path to PDF file
Returns:
Tuple of (text, metadata)
Note: Requires: pip install pdfplumber
Better text extraction than PyPDF2, especially for complex layouts
"""
try:
import pdfplumber
except ImportError:
logger.warning("pdfplumber not installed, falling back to PyPDF2")
return extract_text_pypdf2(pdf_path)
try:
with pdfplumber.open(pdf_path) as pdf:
text = ""
page_texts = {}
for page_num, page in enumerate(pdf.pages):
page_text = page.extract_text()
text += f"\n--- Page {page_num + 1} ---\n{page_text}\n"
page_texts[page_num + 1] = page_text
result_metadata = {
"num_pages": len(pdf.pages),
"title": pdf.metadata.get('Title', 'Unknown') if pdf.metadata else 'Unknown',
"author": pdf.metadata.get('Author', 'Unknown') if pdf.metadata else 'Unknown',
"page_texts": page_texts,
"source_file": os.path.basename(pdf_path)
}
return text, result_metadata
except Exception as e:
logger.error(f"Failed to extract text from {pdf_path}: {e}")
raise
class PDFProcessor:
"""
Process PDF files and extract text for RAG ingestion.
"""
def __init__(self, use_pdfplumber: bool = False):
"""
Initialize PDF processor.
Args:
use_pdfplumber: Use pdfplumber (better) or PyPDF2 (built-in)
"""
self.use_pdfplumber = use_pdfplumber
if use_pdfplumber:
try:
import pdfplumber
logger.info("Using pdfplumber for PDF extraction")
except ImportError:
logger.warning("pdfplumber not installed, using PyPDF2")
self.use_pdfplumber = False
def process_pdf(self, pdf_path: str) -> Tuple[str, Dict]:
"""
Extract text from a single PDF.
Args:
pdf_path: Path to PDF file
Returns:
Tuple of (extracted_text, metadata)
Example:
>>> processor = PDFProcessor()
>>> text, meta = processor.process_pdf("paper.pdf")
>>> print(f"Extracted {meta['num_pages']} pages")
"""
pdf_path = str(pdf_path)
if not os.path.exists(pdf_path):
raise FileNotFoundError(f"PDF not found: {pdf_path}")
if not pdf_path.lower().endswith('.pdf'):
raise ValueError(f"Not a PDF file: {pdf_path}")
logger.info(f"Processing PDF: {os.path.basename(pdf_path)}")
if self.use_pdfplumber:
text, metadata = extract_text_pdfplumber(pdf_path)
else:
text, metadata = extract_text_pypdf2(pdf_path)
logger.info(
f"✓ Extracted {metadata['num_pages']} pages, "
f"{len(text)} chars"
)
return text, metadata
def process_folder(
self,
folder_path: str,
pattern: str = "*.pdf"
) -> Dict[str, Tuple[str, Dict]]:
"""
Process all PDFs in a folder.
Args:
folder_path: Path to folder containing PDFs
pattern: File pattern to match (default: "*.pdf")
Returns:
Dict of {filename: (text, metadata)}
Example:
>>> processor = PDFProcessor()
>>> docs = processor.process_folder("./papers")
>>> for filename, (text, meta) in docs.items():
... print(f"{filename}: {meta['num_pages']} pages")
"""
folder_path = Path(folder_path)
if not folder_path.exists():
raise FileNotFoundError(f"Folder not found: {folder_path}")
logger.info(f"Processing folder: {folder_path}")
pdf_files = list(folder_path.glob(pattern))
logger.info(f"Found {len(pdf_files)} PDF files")
documents = {}
failed = []
for pdf_path in pdf_files:
try:
text, metadata = self.process_pdf(str(pdf_path))
documents[pdf_path.stem] = (text, metadata) # Use filename without extension as key
except Exception as e:
logger.error(f"Failed to process {pdf_path.name}: {e}")
failed.append((pdf_path.name, str(e)))
if failed:
logger.warning(f"Failed to process {len(failed)} files:")
for filename, error in failed:
logger.warning(f" - {filename}: {error}")
logger.info(f"✓ Processed {len(documents)} PDFs successfully")
return documents
def clean_text(self, text: str) -> str:
"""
Clean extracted text (remove extra whitespace, control characters, etc.)
Args:
text: Raw extracted text
Returns:
Cleaned text
"""
# Remove multiple newlines
text = '\n'.join([line.strip() for line in text.split('\n') if line.strip()])
# Remove control characters (but keep newlines and tabs)
text = ''.join(char for char in text if char.isprintable() or char in '\n\t')
return text
# ============ TESTS ============
def test_pdf_processor_missing_file():
"""Test handling of missing file."""
processor = PDFProcessor()
try:
processor.process_pdf("nonexistent.pdf")
assert False, "Should raise FileNotFoundError"
except FileNotFoundError:
print("✓ Correctly raises FileNotFoundError for missing file")
if __name__ == "__main__":
logging.basicConfig(level=logging.INFO)
# Example usage
processor = PDFProcessor(use_pdfplumber=False) |