epub converter: add footnotes, list processing

src/epub_converter.py

@@ -13,9 +13,17 @@ from ebooklib.utils import debug
 
 from src.data_objects import ChapterItem, NavPoint
 from src.html_epub_preprocessor import unwrap_structural_tags, get_tags_between_ids, prepare_title_and_content, \
-    preprocess_image
+    preprocess_image, preprocess_footnotes
 
 
+# epub3 examples:
+# https://github.com/IDPF/epub3-samples
+# specification:
+# https://idpf.github.io/epub-vocabs/structure/
+# footnotes:
+# http://www.theheratik.net/books/tech-epub/chapter-8/
+# http://kb.daisy.org/publishing/docs/html/epub-type.html
+# todo: http://kb.daisy.org/publishing/docs/html/notes.html
 # todo: https://docs.python.org/3/howto/unicode.html
 
 
@@ -34,6 +42,10 @@ class EpubBookAdapter:
 
         self.id_anchor_exist_in_nav_points = False
         self.href2soup_html: Dict[str, BeautifulSoup] = self.build_href2soup_content()
+        self.footnotes = []
+        for href in self.href2soup_html:
+            self.footnotes.extend(preprocess_footnotes(self.href2soup_html[href], self.href2soup_html,
+                                                       noteref_attr_name='data-type'))
         # если в content.opf есть в spine toc атрибут  -> можно найти ncx файл -> из него достать navMap
         # если его там нет, пробуют искать nav tag в manifest -> EpubNav. это у epub3 (не тестировалось todo)
         self.href2ids = defaultdict(list)
@@ -71,8 +83,6 @@ class EpubBookAdapter:
 
     def build_adjacency_list_from_toc(self, element, lvl=0):
         # use book.toc as a root
-        # todo: read _create_section in get_nav
-        # todo: try list on hrefs, extra info in another db
 
         if isinstance(element, Link):
             # todo: check if link exists
@@ -210,7 +220,8 @@ if __name__ == "__main__":
     l = [x.to_dict() for x in top_level_chapters]
 
     tmp = {
-        "content": l
+        "content": l,
+        "footnotes": adapter.footnotes
     }
 
     with codecs.open('tmp.json', 'w', encoding='utf-8') as f:

src/html_epub_preprocessor.py

@@ -1,8 +1,9 @@
 import os
 import pathlib
 import re
+from typing import List
 
-from bs4 import BeautifulSoup, NavigableString
+from bs4 import BeautifulSoup, NavigableString, Tag
 
 from src.access import Access
 
@@ -25,15 +26,16 @@ def save_image_to_aws(access: Access, img_file_path, img_content: bytes, book_id
     return link
 
 
-def preprocess_image(body_tag, href2img_content, path_to_html, access=None):
+def preprocess_image(body_tag: Tag, href2img_content: dict, path_to_html, access=None):
     img_tags = body_tag.find_all('img')
 
     for img in img_tags:
         path_to_img_from_html = img.attrs.get('src')
         html_folder = os.path.dirname(path_to_html)
-        path_to_img_from_root = os.path.normpath(os.path.join(html_folder ,path_to_img_from_html))
+        path_to_img_from_root = os.path.normpath(os.path.join(html_folder, path_to_img_from_html))
 
-        assert path_to_img_from_root in href2img_content, f'Image {path_to_img_from_html} in file {path_to_html} was not added to manifest.'
+        assert path_to_img_from_root in href2img_content, \
+            f'Image {path_to_img_from_html} in file {path_to_html} was not added to manifest.'
 
         img_content = href2img_content[path_to_img_from_root]
         if access is not None:
@@ -44,6 +46,10 @@ def preprocess_image(body_tag, href2img_content, path_to_html, access=None):
         img.attrs['src'] = str(new_folder)
 
 
+def preprocess_figure():
+    pass
+
+
 def preprocess_table():
     pass
 
@@ -52,7 +58,20 @@ def preprocess_quote():
     pass
 
 
-def clean_heading_in_content(content, title: str):
+def _process_lists(body_tag):
+    """
+    Function to process tags <li>.
+    Unwrap <p> tags.
+    """
+    li_tags = body_tag.find_all("li")
+
+    for il_tag in li_tags:
+        if il_tag.p:
+            il_tag.attrs.update(il_tag.p.attrs)
+            il_tag.p.unwrap()
+
+
+def clean_heading_in_content(content: Tag, title: str):
     for child in content.contents:
         if child.text and re.sub(r'([\n\t\xa0])', '', child.text):
             if title == child.text:
@@ -60,8 +79,82 @@ def clean_heading_in_content(content, title: str):
             break
 
 
-def preprocess_footnotes():
+def replace_with_livecarta_anchor_tag(anchor, i):
-    pass
+    new_tag = BeautifulSoup(features='lxml').new_tag('sup')
+    new_tag['class'] = 'footnote-element'
+    new_tag['data-id'] = i + 1
+    new_tag['id'] = f'footnote-{i + 1}'
+    new_tag.string = '*'
+    anchor.replace_with(new_tag)
+
+
+def preprocess_footnotes(source_html_tag: Tag, href2soup_html: dict = None, noteref_attr_name='epub:type') -> List[str]:
+    """
+    This function should be earlier that adding fonts in pipeline.
+
+    <p>Here is an example footnote<sup><a epub:type="noteref" href="#n1">1</a></sup></p>
+    <aside epub:type="footnote" id="n1"><p>With a footnote here.</p></aside>
+
+    """
+    footnotes = []
+    noterefs_tags = source_html_tag.find_all(attrs={noteref_attr_name: 'noteref'})
+    bad_noterefs_tags = set([tag for tag in noterefs_tags if not tag.attrs.get('href')])
+    noterefs_tags = [tag for tag in noterefs_tags if tag not in bad_noterefs_tags]
+    [tag.decompose() for tag in bad_noterefs_tags]
+
+    def parse_a_tag_href(s: str):
+        assert '#' in s, f'Error. Unexpected href: {s} in a tag. Href must contain an id.'
+        f, id_ = s.split('#')
+        return f, id_
+
+    def verify_footnote_tag(tags: list):
+        assert len(tags) <= 1, f'Error, Multiple id: {href}.\n{tags}'
+        if len(tags) == 0:
+            anchored_tags = list(target_html_tag.find_all(id=element_id))
+            if len(anchored_tags):
+                print(f'Warning. Href for tag is detected as footnote:\n{noteref_tag}')
+                return anchored_tags
+            else:
+                assert 0, f'Error, No element with id: {href} found.'
+
+        return tags
+
+    def get_footnote_tags2str(t):
+        unicode_string = ''
+        for child in t.children:
+            if type(child) is NavigableString:
+                unicode_string += str(child)
+            else:
+                unicode_string += child.decode_contents()
+
+        return unicode_string.strip()
+
+    def remove_internal_links_with_text(t):
+        for tag_a in t.find_all('a', {'href': re.compile('(^.+\.(html|xhtml)#.+)|(^#.+)')}):
+            tag_a.decompose()
+
+    for i, noteref_tag in enumerate(noterefs_tags):
+        href = noteref_tag.attrs['href']
+        file, element_id = parse_a_tag_href(href)
+        if not file:
+            target_html_tag = source_html_tag
+        else:
+            target_html_tag = href2soup_html[file]
+
+        possible_footnote = 'note|footnote|endnote|rearenote'
+        expected_footnote_tags = list(target_html_tag.find_all(id=element_id,
+                                                               attrs={'epub:type': re.compile(possible_footnote)}))
+
+        expected_footnote_tags = verify_footnote_tag(expected_footnote_tags)
+        footnote_tag = expected_footnote_tags[0]
+        replace_with_livecarta_anchor_tag(noteref_tag, i)
+        remove_internal_links_with_text(footnote_tag)
+        content = get_footnote_tags2str(footnote_tag)
+
+        footnote_tag.decompose()
+        footnotes.append(content)
+
+    return footnotes
 
 
 def add_fonts():
@@ -145,11 +238,11 @@ def get_tags_between_ids(first_id, href, html_soup):
     return tags
 
 
-def prepare_title_and_content(title, content: BeautifulSoup):
+def prepare_title_and_content(title, content_tag: BeautifulSoup):
     title_str = BeautifulSoup(title, features='lxml').string
     # 0. cleaning \n
     to_remove = []
-    for child in content.contents:
+    for child in content_tag.contents:
         if isinstance(child, NavigableString):
             s = re.sub(r'([\n\t\xa0])', '', child.string)
             if s == '':
@@ -157,8 +250,9 @@ def prepare_title_and_content(title, content: BeautifulSoup):
 
     [x.extract() for x in to_remove]
     # 1. rule#1 for heading removal
-    clean_heading_in_content(content, title_str)
+    clean_heading_in_content(content_tag, title_str)
+    _process_lists(content_tag)
 
-    content_str = re.sub(r'([\n\t\xa0])', ' ', str(content))
+    content_str = re.sub(r'([\n\t\xa0])', ' ', str(content_tag))
     title_str = re.sub(r'([\n\t\xa0])', ' ', title_str)
     return title_str, content_str