5. Text Extraction and Metadata
5. Text Extraction and Metadata
"""
Extract text and manage PDF metadata.
"""
from pypdf import PdfReader, PdfWriter
from pathlib import Path
from typing import Dict, Optional, List
from datetime import datetime
def extract_text(
input_path: str,
pages: Optional[List[int]] = None,
preserve_layout: bool = False
) -> str:
"""Extract text from PDF.
Args:
input_path: Source PDF file
pages: List of page numbers to extract (0-indexed), None for all
preserve_layout: Try to preserve text layout
Returns:
Extracted text as string
"""
reader = PdfReader(input_path)
text_parts = []
target_pages = pages if pages else range(len(reader.pages))
for page_num in target_pages:
if 0 <= page_num < len(reader.pages):
page = reader.pages[page_num]
if preserve_layout:
page_text = page.extract_text(extraction_mode="layout")
else:
page_text = page.extract_text()
if page_text:
text_parts.append(f"--- Page {page_num + 1} ---\n{page_text}")
return "\n\n".join(text_parts)
def extract_text_to_file(
input_path: str,
output_path: str,
pages: Optional[List[int]] = None
) -> int:
"""Extract text from PDF and save to file."""
text = extract_text(input_path, pages)
with open(output_path, 'w', encoding='utf-8') as f:
f.write(text)
word_count = len(text.split())
print(f"Extracted {word_count} words to: {output_path}")
return word_count
def get_pdf_info(input_path: str) -> Dict:
"""Get PDF document information and metadata."""
reader = PdfReader(input_path)
info = {
'file_path': input_path,
'num_pages': len(reader.pages),
'is_encrypted': reader.is_encrypted,
'metadata': {}
}
# Get metadata
if reader.metadata:
metadata = reader.metadata
info['metadata'] = {
'title': metadata.get('/Title', ''),
'author': metadata.get('/Author', ''),
'subject': metadata.get('/Subject', ''),
'creator': metadata.get('/Creator', ''),
'producer': metadata.get('/Producer', ''),
'creation_date': str(metadata.get('/CreationDate', '')),
'modification_date': str(metadata.get('/ModDate', ''))
}
# Get page dimensions of first page
if reader.pages:
first_page = reader.pages[0]
info['page_width'] = float(first_page.mediabox.width)
info['page_height'] = float(first_page.mediabox.height)
info['page_size_inches'] = (
info['page_width'] / 72,
info['page_height'] / 72
)
return info
def set_pdf_metadata(
input_path: str,
output_path: str,
metadata: Dict[str, str]
) -> None:
"""Set PDF metadata.
Args:
input_path: Source PDF file
output_path: Destination file
metadata: Dictionary with keys: title, author, subject, keywords, creator
"""
reader = PdfReader(input_path)
writer = PdfWriter()
# Copy pages
for page in reader.pages:
writer.add_page(page)
# Set metadata
writer.add_metadata({
'/Title': metadata.get('title', ''),
'/Author': metadata.get('author', ''),
'/Subject': metadata.get('subject', ''),
'/Keywords': metadata.get('keywords', ''),
'/Creator': metadata.get('creator', 'pypdf'),
'/Producer': 'pypdf',
'/ModDate': datetime.now().strftime("D:%Y%m%d%H%M%S")
})
writer.write(output_path)
print(f"Metadata updated: {output_path}")
def search_pdf(
input_path: str,
search_term: str,
case_sensitive: bool = False
) -> List[Dict]:
"""Search for text in PDF and return page numbers and context."""
reader = PdfReader(input_path)
results = []
for i, page in enumerate(reader.pages):
text = page.extract_text()
if not text:
continue
search_text = text if case_sensitive else text.lower()
term = search_term if case_sensitive else search_term.lower()
if term in search_text:
# Find context around match
idx = search_text.find(term)
start = max(0, idx - 50)
end = min(len(text), idx + len(term) + 50)
context = text[start:end].replace('\n', ' ')
results.append({
'page': i + 1,
'context': f"...{context}..."
})
return results
# Example usage
# text = extract_text('document.pdf')
# info = get_pdf_info('document.pdf')
# set_pdf_metadata('document.pdf', 'with_metadata.pdf', {
# 'title': 'My Document',
# 'author': 'John Doe',
# 'subject': 'Report'
# })
# results = search_pdf('document.pdf', 'important')
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