pypdf-5-text-extraction-and-metadata

name	pypdf-5-text-extraction-and-metadata
description	Sub-skill of pypdf: 5. Text Extraction and Metadata.
version	1.0.0
category	data
type	reference
scripts_exempt	true

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')