Extraer imagenes de un pdf

extraer.py

# Use python 3
from PyPDF2 import PdfFileReader
from bs4 import BeautifulSoup
import os


def flatten(l):
    """Aplana una lista"""
    if type(l) is not list:
        return [l]
    if len(l) is 0:
        return []
    head, tail = l[0], l[1:]
    return flatten(head) + flatten(tail)


def extract_images_from_resources(resources):
    x_object = resources.get('/XObject')
    if x_object is None:
        return []
    d_objects = {
        # Nos aseguramos que tengamos el objeto
        # y no solo una "referencia"
        name: obj.getObject()
        for (name, obj) in x_object.items()
    }
    return flatten([(
        obj
        if obj['/Subtype'] == '/Image'
        else extract_images_from_resources(obj['/Resources'])
    ) for (name, obj) in d_objects.items()
    ])


def extract_images_from_reader(reader):
    return [
        extract_images_from_resources(reader.getPage(n)['/Resources'])
        for n in range(reader.numPages)
    ]

format_ext_dict = {
    'image/jpeg': '.jpg',
    # Las imagenes de portada y la contraportada indican que son formato Tiff
    # pero en realidad son jpeg
    'image/tiff': '.jpg',
}

with open('libro.pdf', 'rb') as f_pdf:
    reader = PdfFileReader(f_pdf)
    l_imgs = extract_images_from_reader(reader)
    # Creamos el directorio
    os.makedirs('img', exist_ok=True)
    for page, imgs in enumerate(l_imgs):
        for n, img in enumerate(imgs):
            data = img._data
            metadata = img['/Metadata']._data
            # Suponemos que la metadata siempre estara formateada en xml
            metadata_soup = BeautifulSoup(metadata, 'lxml-xml')
            # Extraemos el mimetype de la metadata
            mimetype = metadata_soup.find('Description').attrs.get('format')
            image_path = os.path.join(
                'img', 'page-{}-img-{}{}'.format(
                    page+1, n, format_ext_dict.get(mimetype, '')))
            with open(image_path, 'wb') as f:
                f.write(data)

libro.pdf

requirements.txt