utils.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
utils module for Calibre plugin djvumaker - CLI setup, pdf2djvu installation, and utility methods

References:
(#NODOC)
--- CLI ---
create_cli_parser(self_DJVUmaker, PLUGINNAME, PLUGINVER_DOT, REGISTERED_BACKENDS_KEYS)
ask_yesno_input(question, prints=print)
printProgressBar(iteration, total, prefix = '', suffix = '', decimals = 1, length = 100, fill = '█',
                 prints=print)

--- pdf2djvu installation ---
version_str_to_intlist(verstr)
version_intlist_to_str(verintlist)
version_from_output(output)
check_version_executable(executable_path)
create_backend_link(backend_name, version)
install_pdf2djvu(PLUGINNAME, preferences, log=print)
get_url_basename(url)
download_pdf2djvu(web_version, log)
unpack_zip_or_tar(PLUGINNAME, fpath, log)

--- utility functions ---
EmptyClass()
empty_function(*args, **kwargs)
add_method_dec(method, method_name)
discover_backend(backend_name, preferences, folder)
"""
from __future__ import unicode_literals, division, absolute_import, print_function

import argparse
import os
import urllib
import urllib2
import urlparse
import subprocess

from calibre.constants import isosx, iswindows, islinux, isbsd

def create_cli_parser(self_DJVUmaker, PLUGINNAME, PLUGINVER_DOT, REGISTERED_BACKENDS_KEYS):
    """Creates CLI for plugin."""
    # TODO: add message before and after printing help
    # TODO: add information in cli about current installation and setting and overriding by
    #       customization help
    parser = argparse.ArgumentParser(prog="calibre-debug -r {} -- ".format(PLUGINNAME))
    parser.add_argument('-V', '--version', action='version', version='v{}'.format(PLUGINVER_DOT),
                        help="show plugin's version number and exit")
    subparsers = parser.add_subparsers(metavar='command')
    parser_test = subparsers.add_parser('test')
    parser_test.set_defaults(func=self_DJVUmaker.cli_test)

    parser_backend = subparsers.add_parser('backend', help='Backends handling. See '
                                            '`{}backend --help`'.format(parser.prog))
    parser_backend.set_defaults(func=self_DJVUmaker.cli_backend)
    parser_backend.add_argument('command', choices=['install', 'set'],
                                help='installs or sets backend')
    parser_backend.add_argument('backend', choices=REGISTERED_BACKENDS_KEYS,
                                        help='choosed backend', nargs="?")

    parser_convert = subparsers.add_parser('convert', help='Convert file to djvu')
    parser_convert.set_defaults(func=self_DJVUmaker.cli_convert)
    group_convert = parser_convert.add_mutually_exclusive_group(required=True)
    group_convert.add_argument('-p', "--path",
                                help="convert file under PATH to djvu using default settings",
                                action="store", type=str)
    group_convert.add_argument('-i', "--id",
                                help="convert file with ID to djvu using default settings",
                                action="store", type=int)
    group_convert.add_argument("--all", help=("convert all pdf files in calibre's library, you have to"
                                              " turn on postimport conversion first (`calibre-debug -r"
                                              " djvumaker -- postimport -y`)"),
                                action="store_true")

    parser_postimport = subparsers.add_parser('postimport', help='change postimport settings')
    parser_postimport.set_defaults(func=self_DJVUmaker.cli_set_postimport)
    group_postimport = parser_postimport.add_mutually_exclusive_group(required=False)
    group_postimport.add_argument('-y', "--yes",
                                help=("sets plugin to convert PDF files after import"
                                      " (do not work for pdf2djvu)"),
                                action="store_true")
    group_postimport.add_argument('-n', "--no",
                                help="sets plugin to do not convert PDF files after import (default)",
                                action="store_true")

    parser_install_deps = subparsers.add_parser('install_deps',
        help='(depreciated) alias for `{}backend install djvudigital`'.format(parser.prog))
    parser_install_deps.set_defaults(func=self_DJVUmaker.cli_backend, command='install',
                                     backend='djvudigital')
    parser_convert_all  = subparsers.add_parser('convert_all',
        help='(depreciated) alias for `{}convert --all`'.format(parser.prog))
    parser_convert_all.set_defaults(func=self_DJVUmaker.cli_convert, all=True)
    return parser


def version_str_to_intlist(verstr):
    """Conversion from 'x.y.z' to [x, y, z] version format."""
    return [int(x) for x in verstr.split('.')]
def version_intlist_to_str(verintlist):
    """Conversion from [x, y, z] to 'x.y.z' version format."""
    return '.'.join(map(str,verintlist))

def version_from_output(output):
    """Extracts version number from typical pdf2djvu --version output."""
    return output.splitlines()[0].split()[1]
def check_version_executable(executable_path):
    #NODOC
    return version_from_output(subprocess.check_output([executable_path, '--version'],
        stderr= subprocess.STDOUT))

def discover_backend(backend_name, preferences, folder):
    """
    Discovers backend locations and versions. Currently works only for pdf2djvu.
    Assumes folder structure and existence of backend cli flag --version,
    with output in specific format.

    Side effect:
        If value of version under preferences does not reference to existing installed backend
        it's updates preferences to recognize this issue (set's value of version to None).

    Checks:
        1. Under djvumaker/{backend_name}-{saved_installed_version}/{backend_name}
        2. Under djvumaker/{backend_name}-{other_versions}/{backend_name}
        3. Under {backend_name} (it works if backend_name is on PATH ENV)

    Return values:
    (backend_path, saved_version, best_installed_version, version_under_path)

    Return values description:
        1. backend_path            - path to found backend executable
        2. saved_version           - version saved in plugin JSON file
        3. best_installed_version  - best version in coresponding folder
        4. version_under_path      - version of executable under PATH
    backend_path links to first found version during checks. If it's not found it takes None value.
    If there is no valid version under value 2, 3 or 4, this value is None.
    """
    # Check 1:
    backend_path = None
    saved_version = preferences[backend_name]['version']
    if saved_version is not None:
        try:
            saved_version = check_version_executable(create_backend_link(backend_name, saved_version))
            backend_path = create_backend_link(backend_name, saved_version)
        except OSError:
            saved_version = None
            # Side effect:
            preferences[backend_name]['version'] = None
            preferences.commit()

    # Check 2:
    try:
        folders_list = [filename.split('-') for filename in os.listdir(folder) if os.path.isdir(
            os.path.join(folder, filename))]
        installed_versions = [folder_name[1] for folder_name in folders_list if
            folder_name[0] == backend_name]
        best_installed_version = version_intlist_to_str(sorted(
            [version_str_to_intlist(version) for version in installed_versions])[-1])
        if backend_path is None:
            backend_path = create_backend_link(backend_name, best_installed_version)
    except OSError, IndexError:
        best_installed_version = None

    # Check 3:
    try:
        version_under_path = check_version_executable(backend_name)
        if backend_path is None:
            backend_path = backend_name
    except OSError:
        version_under_path = None

    return backend_path, saved_version, best_installed_version, version_under_path

def create_backend_link(backend_name, version):
    #NODOC
    return os.path.join(os.path.join('djvumaker', '{}-{}'.format(backend_name, version), backend_name))

# TODO:
# class Installer_pdf2djvu(Installer):
#     pass

def install_pdf2djvu(PLUGINNAME, preferences, log=print):
    #NODOC
    backend_path, saved_version, installed_version, path_version = discover_backend('pdf2djvu',
        preferences, PLUGINNAME)
    log("DEBUG: ", (backend_path, saved_version, installed_version, path_version))

    local_version = None
    if saved_version is None and installed_version is None:
        log('pdf2djvu was not found in plugin directory.')
        if path_version is not None:
            log('Version {} of pdf2djvu was found on your local path env.'.format(path_version))
            local_version = path_version
        else:
            log('pdf2djvu was not found on your local path env.')
    else:
        if saved_version is None or (installed_version is not None and saved_version is not None
                and version_str_to_intlist(installed_version) > version_str_to_intlist(saved_version)):
            saved_version = installed_version
            preferences['pdf2djvu']['version'] = installed_version
            preferences.commit()
        log('Version {} of pdf2djvu was found in plugin directory.'.format(saved_version))
        local_version = saved_version


    log("Checking pdf2djvu's author page for current relase...")
    github_latest_url = r'https://github.com/jwilk/pdf2djvu/releases/latest'
    # DEBUG UNCOMMENT
    github_page = urllib2.urlopen(github_latest_url)
    web_version = get_url_basename(github_page.geturl())

    # DEBUG COMMENT
    # web_version = '0.9.5'
    # local_version = None

    log('Version {} of pdf2djvu is available on program\'s GitHub page.'.format(web_version))

    def check_extracted_archive_pdf2djvu(exec_path, asked_version):
        dir_path = os.path.dirname(exec_path)
        output_version = check_version_executable(exec_path)
        if output_version != asked_version:
            raise Exception('Extracted file has wrong version.')

    def download_and_unpack():
        try:
            fpath = download_pdf2djvu(web_version, log)
        except:
            msg = ('Error occured during downloading new relase, you can try manually download current'
                   ' relase from {} and extract it inside calibre{sep}plugins{sep}djvumaker'
                  ).format(github_latest_url, os.getcwd(), sep=os.pathsep)
            log(msg)
            raise
        try:
            unpack_zip_or_tar(PLUGINNAME, fpath, log)
            check_extracted_archive_pdf2djvu(create_backend_link('pdf2djvu', web_version), web_version)
            log('Extracting verified.')
        except:
            msg = ('Error occured during unpacking, check {}{sep}djvumaker folder for archive and try'
                   ' extract it manually inside calibre{sep}plugins{sep}djvumaker'
                  ).format(os.getcwd(), sep=os.pathsep)
            log(msg)
            raise

    if local_version is None:
        if not ask_yesno_input('Do you want to download current version of pdf2djvu?', log):
            return False, None
        download_and_unpack()
        return True, web_version

    local_ver_intlist = version_str_to_intlist(local_version)
    new_ver_intlist  = version_str_to_intlist(web_version)
    if new_ver_intlist == local_ver_intlist:
        log('You already have locally current version of pdf2djvu.')
        if saved_version is None and installed_version is None:
            if ask_yesno_input("Do you want to redownload current version of pdf2djvu to plugin\'s"
                               " directory? (it isn't necessary)"):
                download_and_unpack()
                return True, local_version
            else:
                return False, None
        return True, local_version
    elif new_ver_intlist > local_ver_intlist:
        if not ask_yesno_input(
            'Do you want to download newer version of pdf2djvu to plugin\'s directory?', log):
            return False, None
        download_and_unpack()
        return True, web_version
    else: #new_ver_intlist < local_ver_intlist
        raise Exception("Newer local version than current pdf2djvu found.")

def get_url_basename(url):
    #NODOC
    return os.path.basename(urlparse.urlsplit(url).path)

def download_pdf2djvu(web_version, log):
    #NODOC
    def gen_zip_url(code):
        #NODOC
        return r'https://github.com/jwilk/pdf2djvu/releases/download/{}/pdf2djvu-win32-{}.zip'.format(code, code)
    def gen_tar_url(code):
        #NODOC
        return r'https://github.com/jwilk/pdf2djvu/releases/download/{}/pdf2djvu-{}.tar.xz'.format(code, code)

    # TODO: what with fallback!?! new argument
    fallback_version = '0.9.5'
    if iswindows:
        fallback_arch_url = gen_zip_url(fallback_version)
        arch_url = gen_zip_url(web_version)
    else:
        fallback_arch_url = gen_tar_url(fallback_version)
        arch_url = gen_tar_url(web_version)

    def download_progress_bar(i, chunk, full):
        """'args: a count of blocks transferred so far,
        a block size in bytes, and the total size of the file"""
        printProgressBar(i*chunk, full, prefix = '\tProgress:', suffix = 'Complete',
                         length=50, prints=print)

    def check_msg(fpath, msg):
        return (
                'Content-Length' in msg and int(msg['Content-Length']) > 0
            and 'Content-Type' in msg and msg['Content-Type'].split('/')[0] == 'application'
            and 'Content-Disposition' in msg
            and msg['Content-Disposition'].split(';')[0] == 'attachment'
            and msg['Content-Disposition'].split(';')[1].strip() == 'filename={}'.format(
                os.path.basename(fpath))
                )

    log('Downloading current version of pdf2djvu...')
    if not os.path.isdir('djvumaker'):
        os.mkdir('djvumaker')
    fpath, msg = urllib.urlretrieve(arch_url, os.path.join('.', 'djvumaker', get_url_basename(arch_url)),
                                    download_progress_bar)
    # print() # should progess bar function handle this TODO:
    if not check_msg(fpath, msg):
        log('Cannot download current version {} from GitHub.'.format(web_version))
        if web_version != fallback_version:
            log('Trying download version {}...'.format(fallback_version), download_progress_bar)
            fpath, msg_fallback = urllib.urlretrieve(fallback_arch_url, os.path.join('.','djvumaker',
                                                     get_url_basename(fallback_arch_url)),
                                                     download_progress_bar)
            # print() # should progess bar function handle this TODO:
            if not check_msg(fpath, msg_fallback):
                raise Exception('Cannot download pdf2djvu.')
    else:
        log('Dowloaded {} file'.format(os.path.abspath(fpath)))
    return fpath

def unpack_zip_or_tar(PLUGINNAME, fpath, log):
    #NODOC
    # DEBUG COMMENT
    # log(fpath)
    log('Extracting now...')
    if iswindows:
        from zipfile import ZipFile
        with ZipFile(fpath, 'r') as myzip:
            myzip.extractall(os.path.dirname(fpath))
    else:
        # Python 2.7 Standard Library cannot unpack tar.xz archive, do this manually or through shell
        # it can not work on macOS
        subprocess.call(['tar', 'xf', fpath, '-C', os.path.dirname(fpath)])
        # TODO: you have to make it still...
        # doesn't work for linux or mac then
    log('Extracted downloaded archive')
    os.remove(fpath)
    log('Removed downloaded archive')

# Print iterations progress
def printProgressBar(iteration, total, prefix = '', suffix = '', decimals = 1, length = 100, fill = '█',
                     prints=print):
    """
    source: http://stackoverflow.com/a/34325723/2351523
    Call in a loop to create terminal progress bar
    @params:
        iteration   - Required  : current iteration (Int)
        total       - Required  : total iterations (Int)
        prefix      - Optional  : prefix string (Str)
        suffix      - Optional  : suffix string (Str)
        decimals    - Optional  : positive number of decimals in percent complete (Int)
        length      - Optional  : character length of bar (Int)
        fill        - Optional  : bar fill character (Str)
    """
    percent = ("{0:." + str(decimals) + "f}").format(100 * (iteration / float(total)))
    filledLength = int(length * iteration // total)
    bar = fill * filledLength + '-' * (length - filledLength)
    prints('\r%s |%s| %s%% %s' % (prefix, bar, percent, suffix), end = '\r')
    # Print New Line on Complete
    if iteration >= total:
        prints()

def ask_yesno_input(question, prints=print):
    """Ask user for yes/no input. Loops if other answer."""
    while True:
        prints('\n\t'+ question + ' (y/n)\n')
        user_input = raw_input().strip().lower()
        if user_input == 'y':
            return True
        elif user_input == 'n':
            return False
        else:
            prints("Your input is not 'y' or 'n'.")

class EmptyClass():
    pass
def empty_function(*args, **kwargs):
    pass

def add_method_dec(obj, name):
    """Decorate `fun`, add `obj` as attribute with name `name` to `fun`"""
    def inner(fun):
        setattr(fun, name, obj)
        return fun
    return inner