215 lines
7.0 KiB
Python
215 lines
7.0 KiB
Python
from __future__ import unicode_literals
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from io import BytesIO
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import logging
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import os
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import shutil
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from PIL import Image
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import sh
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import yaml
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try:
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from yaml import CSafeLoader as SafeLoader
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except ImportError:
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from yaml import SafeLoader
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from django.utils.translation import ugettext_lazy as _
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from mayan.apps.mimetype.api import get_mimetype
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from mayan.apps.storage.settings import setting_temporary_directory
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from mayan.apps.storage.utils import (
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NamedTemporaryFile, fs_cleanup, mkdtemp
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)
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from .exceptions import InvalidOfficeFormat, OfficeConversionError
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from .literals import (
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CONVERTER_OFFICE_FILE_MIMETYPES, DEFAULT_LIBREOFFICE_PATH,
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DEFAULT_PAGE_NUMBER, DEFAULT_PILLOW_FORMAT
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)
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from .settings import setting_graphics_backend_config
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logger = logging.getLogger(__name__)
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BACKEND_CONFIG = yaml.load(
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stream=setting_graphics_backend_config.value, Loader=SafeLoader
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)
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libreoffice_path = BACKEND_CONFIG.get(
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'libreoffice_path', DEFAULT_LIBREOFFICE_PATH
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)
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class ConverterBase(object):
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def __init__(self, file_object, mime_type=None):
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self.file_object = file_object
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self.image = None
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self.mime_type = mime_type or get_mimetype(
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file_object=file_object, mimetype_only=False
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)[0]
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self.soffice_file = None
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Image.init()
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try:
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self.command_libreoffice = sh.Command(libreoffice_path).bake(
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'--headless', '--convert-to', 'pdf:writer_pdf_Export'
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)
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except sh.CommandNotFound:
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self.command_libreoffice = None
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def convert(self, page_number=DEFAULT_PAGE_NUMBER):
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self.page_number = page_number
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def detect_orientation(self, page_number):
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# Must be overrided by subclass
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pass
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def get_page(self, output_format=None):
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output_format = output_format or yaml.load(
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stream=setting_graphics_backend_config.value, Loader=SafeLoader
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).get(
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'pillow_format', DEFAULT_PILLOW_FORMAT
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)
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if not self.image:
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self.seek_page(page_number=0)
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image_buffer = BytesIO()
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new_mode = self.image.mode
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if output_format.upper() == 'JPEG':
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# JPEG doesn't support transparency channel, convert the image to
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# RGB. Removes modes: P and RGBA
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new_mode = 'RGB'
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self.image.convert(new_mode).save(image_buffer, format=output_format)
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image_buffer.seek(0)
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return image_buffer
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def get_page_count(self):
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try:
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self.soffice_file = self.to_pdf()
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except InvalidOfficeFormat as exception:
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logger.debug('Is not an office format document; %s', exception)
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def seek_page(self, page_number):
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"""
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Seek the specified page number from the source file object.
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If the file is a paged image get the page if not convert it to a
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paged image format and return the specified page as an image.
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"""
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# Starting with #0
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self.file_object.seek(0)
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try:
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self.image = Image.open(self.file_object)
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except IOError:
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# Cannot identify image file
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self.image = self.convert(page_number=page_number)
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else:
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self.image.seek(page_number)
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self.image.load()
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def soffice(self):
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"""
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Executes LibreOffice as a subprocess
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"""
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if not self.command_libreoffice:
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raise OfficeConversionError(
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_('LibreOffice not installed or not found.')
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)
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with NamedTemporaryFile() as temporary_file_object:
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# Copy the source file object of the converter instance to a
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# named temporary file to be able to pass it to the LibreOffice
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# execution.
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self.file_object.seek(0)
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shutil.copyfileobj(
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fsrc=self.file_object, fdst=temporary_file_object
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)
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self.file_object.seek(0)
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temporary_file_object.seek(0)
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libreoffice_home_directory = mkdtemp()
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args = (
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temporary_file_object.name, '--outdir', setting_temporary_directory.value,
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'-env:UserInstallation=file://{}'.format(
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os.path.join(
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libreoffice_home_directory, 'LibreOffice_Conversion'
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)
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),
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)
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kwargs = {'_env': {'HOME': libreoffice_home_directory}}
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if self.mime_type == 'text/plain':
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kwargs.update(
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{'infilter': 'Text (encoded):UTF8,LF,,,'}
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)
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try:
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self.command_libreoffice(*args, **kwargs)
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except sh.ErrorReturnCode as exception:
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temporary_file_object.close()
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raise OfficeConversionError(exception)
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except Exception as exception:
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temporary_file_object.close()
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logger.error('Exception launching Libre Office; %s', exception)
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raise
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finally:
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fs_cleanup(libreoffice_home_directory)
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# LibreOffice return a PDF file with the same name as the input
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# provided but with the .pdf extension.
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# Get the converted output file path out of the temporary file
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# name plus the temporary directory
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filename, extension = os.path.splitext(
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os.path.basename(temporary_file_object.name)
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)
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logger.debug('filename: %s', filename)
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logger.debug('extension: %s', extension)
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converted_file_path = os.path.join(
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setting_temporary_directory.value, os.path.extsep.join(
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(filename, 'pdf')
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)
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)
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logger.debug('converted_file_path: %s', converted_file_path)
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# Don't use context manager with the NamedTemporaryFile on purpose
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# so that it is deleted when the caller closes the file and not
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# before.
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temporary_converted_file_object = NamedTemporaryFile()
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# Copy the LibreOffice output file to a new named temporary file
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# and delete the converted file
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with open(converted_file_path, mode='rb') as converted_file_object:
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shutil.copyfileobj(
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fsrc=converted_file_object, fdst=temporary_converted_file_object
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)
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fs_cleanup(converted_file_path)
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temporary_converted_file_object.seek(0)
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return temporary_converted_file_object
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def to_pdf(self):
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if self.mime_type in CONVERTER_OFFICE_FILE_MIMETYPES:
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return self.soffice()
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else:
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raise InvalidOfficeFormat(_('Not an office file format.'))
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def transform(self, transformation):
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if not self.image:
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self.seek_page(page_number=0)
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self.image = transformation.execute_on(image=self.image)
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def transform_many(self, transformations):
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if not self.image:
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self.seek_page(page_number=0)
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for transformation in transformations:
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self.image = transformation.execute_on(image=self.image)
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