openmedialibrary/oml/media/epub.py

# -*- coding: utf-8 -*-
# vi:si:et:sw=4:sts=4:ts=4


import os
import xml.etree.ElementTree as ET
import zipfile
import re
from urllib.parse import unquote
import lxml.html
from io import BytesIO

from PIL import Image

from ox import strip_tags, decode_html, normalize_name

from utils import find_isbns, get_language, to_isbn13

import logging
logging.getLogger('PIL').setLevel(logging.ERROR)
logger = logging.getLogger(__name__)


def get_ratio(data):
    try:
        img = Image.open(BytesIO(data))
        return img.size[0]/img.size[1]
    except:
        return -1

def normpath(path):
    return '/'.join(os.path.normpath(path).split(os.sep))

def cover(path):
    logger.debug('cover %s', path)
    data = None
    try:
        z = zipfile.ZipFile(path)
    except zipfile.BadZipFile:
        logger.debug('invalid epub file %s', path)
        return data

    def use(filename):
        logger.debug('using %s', filename)
        try:
            data = z.read(filename)
        except:
            return None
        r = get_ratio(data)
        if r < 0.3 or r > 2:
            return None
        return data

    files = []
    for f in z.filelist:
        if f.filename == 'calibre-logo.png':
            continue
        if 'cover' in f.filename.lower() and f.filename.split('.')[-1] in ('jpg', 'jpeg', 'png'):
            return use(f.filename)
        files.append(f.filename)
    opf = [f for f in files if f.endswith('opf')]
    if opf:
        #logger.debug('opf: %s', z.read(opf[0]).decode())
        info = ET.fromstring(z.read(opf[0]))
        metadata = info.findall('{http://www.idpf.org/2007/opf}metadata')
        if metadata:
            metadata = metadata[0]
        manifest = info.findall('{http://www.idpf.org/2007/opf}manifest')
        if manifest:
            manifest = manifest[0]
        if metadata and manifest:
            for e in metadata.getchildren():
                if e.tag == '{http://www.idpf.org/2007/opf}meta' and e.attrib.get('name') == 'cover':
                    cover_id = e.attrib['content']
                    for e in manifest.getchildren():
                        if e.attrib['id'] == cover_id:
                            filename = unquote(e.attrib['href'])
                            filename = normpath(os.path.join(os.path.dirname(opf[0]), filename))
                            if filename in files:
                                return use(filename)
        if manifest:
            images = [e for e in manifest.getchildren() if 'image' in e.attrib['media-type']]
            if images:
                image_data = []
                for e in images:
                    filename = unquote(e.attrib['href'])
                    filename = normpath(os.path.join(os.path.dirname(opf[0]), filename))
                    if filename in files:
                        image_data.append(filename)
                if image_data:
                    image_data.sort(key=lambda name: z.getinfo(name).file_size)
                    return use(image_data[-1])
            for e in manifest.getchildren():
                if 'html' in e.attrib['media-type']:
                    filename = unquote(e.attrib['href'])
                    filename = normpath(os.path.join(os.path.dirname(opf[0]), filename))
                    html = z.read(filename).decode('utf-8', 'ignore')
                    img = re.compile('<img.*?src="(.*?)"').findall(html)
                    #svg image
                    img += re.compile('<image.*?href="(.*?)"').findall(html)
                    if img:
                        img = unquote(img[0])
                        img = normpath(os.path.join(os.path.dirname(filename), img))
                        if img in files:
                            return use(img)
    return data

def info(epub):
    data = {}
    try:
        z = zipfile.ZipFile(epub)
    except zipfile.BadZipFile:
        logger.debug('invalid epub file %s', epub)
        return data
    files = [f.filename for f in z.filelist]
    opf = [f for f in files if f.endswith('opf')]
    if opf:
        info = ET.fromstring(z.read(opf[0]))
        metadata = info.findall('{http://www.idpf.org/2007/opf}metadata')
        if metadata:
            metadata = metadata[0]
            for e in metadata.getchildren():
                if e.text and e.text.strip() and e.text not in ('unknown', 'none'):
                    key = e.tag.split('}')[-1]
                    key = {
                        'creator': 'author',
                    }.get(key, key)
                    value = e.text.strip()
                    if key == 'identifier':
                        value = to_isbn13(value)
                        if value:
                            data['isbn'] = value
                    elif key == 'author':
                        data[key] = value.split(', ')
                        if len(data[key]) == 2 and max(len(d.split(' ')) for d in data[key]) == 1:
                            data[key] = [normalize_name(', '.join(data[key]))]
                    else:
                        data[key] = value
        toc = [f for f in files if 'toc.ncx' in f]
        if toc:
            try:
                _toc = ET.fromstring(z.read(toc[0]))
                nav_map = _toc.find('{http://www.daisy.org/z3986/2005/ncx/}navMap')
            except:
                logger.debug('failed to parse toc', exc_info=True)
                nav_map = None
            if nav_map:
                contents = []
                for point in nav_map.findall('{http://www.daisy.org/z3986/2005/ncx/}navPoint'):
                    label = point.find('{http://www.daisy.org/z3986/2005/ncx/}navLabel')
                    if label:
                        txt = label.getchildren()[0].text
                        if txt:
                            contents.append(txt)
                if contents:
                    data['tableofcontents'] = '\n'.join(contents).strip()
        if not 'tableofcontents' in data:
            guide = info.find('{http://www.idpf.org/2007/opf}guide')
            if guide:
                for ref in guide.findall('{http://www.idpf.org/2007/opf}reference'):
                    if ref.attrib.get('type') == 'toc':
                        filename = unquote(ref.attrib['href']).split('#')[0]
                        filename = normpath(os.path.join(os.path.dirname(opf[0]), filename))
                        if filename in files:
                            toc = z.read(filename)
                            if toc:
                                doc = lxml.html.document_fromstring(toc)
                                data['tableofcontents'] = '\n'.join([a.text_content() for a in doc.xpath('//a')]).strip()
    if 'description' in data:
        data['description'] = strip_tags(decode_html(data['description']))
    text = extract_text(epub)
    data['textsize'] = len(text)
    if not 'isbn' in data:
        isbn = extract_isbn(text)
        if isbn:
            data['isbn'] = isbn
    if 'date' in data and 'T' in data['date']:
        data['date'] = data['date'].split('T')[0]
    if 'language' in data and isinstance(data['language'], str):
        data['language'] = get_language(data['language'])
    for key in list(data):
        if isinstance(data[key], str) and not data[key].strip():
            del data[key]
    return data

def extract_text(path):
    data = ''
    z = zipfile.ZipFile(path)
    for f in z.filelist:
        if '/._' in f.filename or f.filename.startswith('._'):
            continue
        if 'META-INF' in f.filename:
            continue
        if f.filename.split('.')[-1] in ('html', 'xml', 'htm'):
            data += z.read(f.filename).decode('utf-8', 'ignore')
    return data

def extract_isbn(data):
    isbns = find_isbns(data)
    if isbns:
        return isbns[0]