How to Check if Two PDF Documents are Identical in Python

import hashlib
import os

def get_file_hash(filepath):
    """Generate SHA-256 hash of file contents."""
    hasher = hashlib.sha256()
    with open(filepath, "rb") as f:
        while chunk := f.read(65536):
            hasher.update(chunk)
    return hasher.hexdigest()

def is_exact_match(pdf1, pdf2):
    """Check if two PDFs are byte-for-byte identical."""
    if os.path.getsize(pdf1) != os.path.getsize(pdf2):
        return False
    
    return get_file_hash(pdf1) == get_file_hash(pdf2)

if is_exact_match("report_v1.pdf", "report_backup.pdf"):
    print("Files are identical")
else:
    print("Files differ")

pip install pymupdf

import fitz  # PyMuPDF

def extract_text(filepath):
    """Extract all text from a PDF document."""
    doc = fitz.open(filepath)
    text = ""
    for page in doc:
        text += page.get_text()
    doc.close()
    return text

def is_content_match(pdf1, pdf2):
    """Compare PDFs by text content, ignoring metadata."""
    text1 = extract_text(pdf1)
    text2 = extract_text(pdf2)
    
    normalized1 = " ".join(text1.split())
    normalized2 = " ".join(text2.split())
    
    return normalized1 == normalized2

if is_content_match("contract_v1.pdf", "contract_v2.pdf"):
    print("Documents contain the same text")
else:
    print("Text content differs")

import fitz
import difflib

def compare_text_detailed(pdf1, pdf2):
    """Generate a detailed diff of text differences."""
    text1 = extract_text(pdf1).splitlines()
    text2 = extract_text(pdf2).splitlines()
    
    diff = difflib.unified_diff(
        text1,
        text2,
        fromfile=pdf1,
        tofile=pdf2,
        lineterm=""
    )
    
    return list(diff)

differences = compare_text_detailed("doc_old.pdf", "doc_new.pdf")
if differences:
    print("Differences found:")
    for line in differences[:20]:  # Show first 20 lines
        print(line)
else:
    print("No text differences")

pip install pdf2image pillow

from pdf2image import convert_from_path
from PIL import ImageChops
import os

def compare_visual(pdf1, pdf2, dpi=150):
    """Compare PDFs visually by converting to images."""
    images1 = convert_from_path(pdf1, dpi=dpi)
    images2 = convert_from_path(pdf2, dpi=dpi)
    
    if len(images1) != len(images2):
        return False, f"Page count differs: {len(images1)} vs {len(images2)}"
    
    for i, (img1, img2) in enumerate(zip(images1, images2)):
        if img1.size != img2.size:
            return False, f"Page {i+1} dimensions differ"
        
        diff = ImageChops.difference(img1, img2)
        if diff.getbbox() is not None:
            return False, f"Page {i+1} has visual differences"
    
    return True, "Documents are visually identical"

match, message = compare_visual("layout_v1.pdf", "layout_v2.pdf")
print(message)

from pdf2image import convert_from_path
from PIL import Image, ImageChops, ImageDraw

def save_visual_diff(pdf1, pdf2, output_dir="diff_output"):
    """Generate diff images highlighting visual differences."""
    os.makedirs(output_dir, exist_ok=True)
    
    images1 = convert_from_path(pdf1, dpi=150)
    images2 = convert_from_path(pdf2, dpi=150)
    
    differences = []
    
    for i, (img1, img2) in enumerate(zip(images1, images2)):
        diff = ImageChops.difference(img1.convert("RGB"), img2.convert("RGB"))
        
        if diff.getbbox():
            diff = diff.point(lambda x: min(255, x * 10))
            diff.save(f"{output_dir}/page_{i+1}_diff.png")
            differences.append(i + 1)
    
    return differences

diff_pages = save_visual_diff("before.pdf", "after.pdf")
if diff_pages:
    print(f"Differences on pages: {diff_pages}")

import hashlib
import os
import fitz
from pdf2image import convert_from_path
from PIL import ImageChops

def compare_pdfs(pdf1, pdf2, mode="auto"):
    """
    Compare two PDFs using specified mode.
    
    Modes:
        - 'binary': Exact byte comparison (fastest)
        - 'text': Text content comparison
        - 'visual': Pixel-by-pixel comparison (slowest)
        - 'auto': Try binary first, then text if different
    """
    result = {
        "identical": False,
        "mode_used": mode,
        "details": ""
    }
    
    if mode in ("binary", "auto"):
        if os.path.getsize(pdf1) == os.path.getsize(pdf2):
            if get_file_hash(pdf1) == get_file_hash(pdf2):
                result["identical"] = True
                result["mode_used"] = "binary"
                result["details"] = "Files are byte-for-byte identical"
                return result
        
        if mode == "binary":
            result["details"] = "Binary content differs"
            return result
    
    if mode in ("text", "auto"):
        if is_content_match(pdf1, pdf2):
            result["identical"] = True
            result["mode_used"] = "text"
            result["details"] = "Text content matches (metadata may differ)"
            return result
        
        result["details"] = "Text content differs"
        return result
    
    if mode == "visual":
        match, message = compare_visual(pdf1, pdf2)
        result["identical"] = match
        result["details"] = message
        return result
    
    return result

result = compare_pdfs("doc1.pdf", "doc2.pdf", mode="auto")
print(f"Identical: {result['identical']}")
print(f"Method: {result['mode_used']}")
print(f"Details: {result['details']}")