example_preprocessor.py

#!/usr/bin/python
# The parameter list is type, folder
# where "type" is one of 'ebook', 'audiobook', 'mag', 'test'
# and "folder" is the folder ready to be processed
# This example uses "ebook-convert" from calibre to make sure we have both epub and mobi of the new book.
# Note it is not fully error trapped, just a basic working example.
# Error messages appear as errors in the lazylibrarian log
# Anything you print to stdout appears as debug messages in the log
# The exit code and messages get passed back to the "test" button
# Always exit zero on success, non-zero on fail

import os
import subprocess
import sys
import time

converter = "ebook-convert"  # if not in your "path", put the full pathname here
# set these to your preferences
wanted_formats = ['.epub', '.mobi']
keep_opf = True
keep_jpg = True
delete_others = False  # use with care, deletes everything except wanted formats (and opf/jpg if keep is True)


def makeBytestr(txt):
    # convert unicode to bytestring, needed for os.walk and os.listdir
    # listdir falls over if given unicode startdir and a filename in a subdir can't be decoded to ascii
    if not txt:
        return b''
    elif not isinstance(txt, text_type):  # nothing to do if already bytestring
        return txt
    for encoding in ['utf-8', 'latin-1']:
        try:
            txt = txt.encode(encoding)
            return txt
        except UnicodeError:
            pass
    return txt


def makeUnicode(txt):
    # convert a bytestring to unicode, don't know what encoding it might be so try a few
    # it could be a file on a windows filesystem, unix...
    if not txt:
        return u''
    elif isinstance(txt, text_type):
        return txt
    for encoding in ['utf-8', 'latin-1']:
        try:
            txt = txt.decode(encoding)
            return txt
        except UnicodeError:
            pass
    return txt


if len(sys.argv) != 3:
    sys.stderr.write("Invalid parameters (%s) assume test\n" % len(sys.argv))
    booktype = 'test'
    bookfolder = ''
else:
    booktype = sys.argv[1]
    bookfolder = sys.argv[2]


if sys.version_info[0] == 3:
    text_type = str
else:
    text_type = unicode

with open(os.path.join(os.path.dirname(os.path.abspath(__file__)), 'preprocessor.log'), 'a') as pplog:
    pplog.write("%s: %s %s\n" % (time.ctime(), booktype, bookfolder))
    if not booktype or booktype not in ['ebook', 'audiobook', 'mag', 'test']:
        sys.stderr.write("%s %s\n" % ("Invalid booktype", booktype))
        pplog.write("%s: %s %s\n" % (time.ctime(), "Invalid booktype", booktype))
        exit(1)
    if not os.path.exists(bookfolder) and booktype != 'test':
        sys.stderr.write("%s %s\n" % ("Invalid bookfolder", bookfolder))
        pplog.write("%s: %s %s\n" % (time.ctime(), "Invalid bookfolder", bookfolder))
        exit(1)

    if booktype == 'test':
        print("Preprocessor test")
        if not os.path.exists(bookfolder):
            bookfolder = os.path.dirname(os.path.abspath(__file__))

    if booktype == 'ebook' or booktype == 'test':
        sourcefile = None
        basename = None
        source_extn = None
        created = ''
        for fname in os.listdir(makeBytestr(bookfolder)):
            fname = makeUnicode(fname)
            filename, extn = os.path.splitext(fname)
            if extn == '.epub':
                sourcefile = fname
                break
            elif extn == '.mobi':
                sourcefile = fname
                break

        pplog.write("Wanted formats: %s\n" % str(wanted_formats))
        if not sourcefile:
            if booktype == 'test':
                print("No suitable sourcefile found in %s" % bookfolder)
            else:
                sys.stderr.write("%s %s\n" % ("No suitable sourcefile found in", bookfolder))
            pplog.write("%s: %s %s\n" % (time.ctime(), "No suitable sourcefile found in", bookfolder))
        else:
            basename, source_extn = os.path.splitext(sourcefile)
            for ftype in wanted_formats:
                if not os.path.exists(os.path.join(bookfolder, basename + ftype)):
                    pplog.write("No %s\n" % ftype)
                    params = [converter, os.path.join(bookfolder, sourcefile),
                              os.path.join(bookfolder, basename + ftype)]
                    if ftype == '.mobi':
                        params.extend(['--output-profile', 'kindle'])
                    try:
                        res = subprocess.check_output(params, stderr=subprocess.STDOUT)
                        if created:
                            created += ' '
                        created += ftype
                    except Exception as e:
                        sys.stderr.write("%s\n" % e)
                        pplog.write("%s: %s\n" % (time.ctime(), e))
                        exit(1)
                else:
                    pplog.write("Found %s\n" % ftype)

        if delete_others:
            if keep_opf:
                wanted_formats.append('.opf')
            if keep_jpg:
                wanted_formats.append('.jpg')
            for fname in os.listdir(makeBytestr(bookfolder)):
                fname = makeUnicode(fname)
                filename, extn = os.path.splitext(fname)
                if not extn or extn.lower() not in wanted_formats:
                    if booktype == 'test':
                        print("Would delete %s" % fname)
                        pplog.write("Would delete %s\n" % fname)
                    else:
                        print("Deleting %s" % fname)
                        pplog.write("Deleting %s\n" % fname)
                        try:
                            os.remove(os.path.join(bookfolder, fname))
                        except OSError:
                            pass
        if created:
            print("Created %s from %s" % (created, source_extn))
            pplog.write("%s: Created %s from %s\n" % (time.ctime(), created, source_extn))
        else:
            print("No extra ebook formats created")
            pplog.write("%s: No extra ebook formats created\n" % time.ctime())
    elif booktype == 'audio':
        # maybe you want a zip archive of the audiobook, or create a playlist?
        print("This example preprocessor only preprocesses eBooks")
    elif booktype == 'mag':
        # maybe you want to split the pages and turn them into jpeg like a comic?
        print("This example preprocessor only preprocesses eBooks")

exit(0)