Making EPUBs in Python is a non-trivial task. While the appearance of grabbing x number of HTML documents and throwing running them through the zipfile module seems straight forward, there are things you must consider. While there are a number of ‘rules’, these are the two that I had the biggest problem with – things that differentiate them from just zipping up some files.

1. There must be a metafile document, and it must be the first document in the archive.
2. There is an index file (ending in .opf), which is an index of all the files in the EPUB.

It would also be a good idea to read the spec on EPUB 3.0 before proceeding to understand the format expected.

Let’s look at some code.

import os.path
import zipfile
import tempfile
import shutil

epub = "simultaneous-equations-1.1.epub"
output_file = "my-epub.epub"
build_dir = tempfile.gettempdir()
resting_place = "/home/michael/Documents"

with zipfile.ZipFile(output_file, 'w') as epub:
 # add mimetype (must be first!)
 with open("mimetype", "r") as mime:
   epub.writestr("mimetype", mime.read().replace('\n', ''))

 # add META
 with open("META-INF/container.xml", "r") as meta:
   epub.writestr("META-INF/container.xml", meta.read())

 # content
 for (root, dirs, files) in os.walk('content'):
   for file in files:
     file_path = os.path.join(root, file)
     epub.write(file_path)

 #resources
 for (root, dirs, files) in os.walk('resources'):
   for file in files:
     file_path = os.path.join(root, file)
     epub.write(file_path)

# move this to it's final resting place
shutil.copy(os.path.join(build_dir, output_file), resting_place)