88 lines
3.0 KiB
Python
88 lines
3.0 KiB
Python
from __future__ import unicode_literals
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import logging
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from django.utils.module_loading import import_string
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from converter import converter_class
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from .exceptions import NoMIMETypeMatch, ParserError
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from .models import DocumentPageContent
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from .parsers import Parser
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from .settings import setting_ocr_backend
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logger = logging.getLogger(__name__)
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class TextExtractor(object):
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@classmethod
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def perform_ocr(cls, document_page):
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ocr_backend_class = import_string(setting_ocr_backend.value)
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backend = ocr_backend_class()
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backend.process_document_page(document_page)
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@classmethod
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def process_document_page(cls, document_page):
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"""
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Extract text for a document version's page. Try parsing the page and if
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no there are not parsers for the MIME type or the parser return nothing
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fallback to doing and OCR of the page.
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"""
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try:
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Parser.parse_document_page(document_page=document_page)
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except (NoMIMETypeMatch, ParserError):
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cls.perform_ocr(document_page=document_page)
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else:
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if not document_page.ocr_content.content:
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cls.perform_ocr(document_page=document_page)
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@classmethod
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def process_document_version(cls, document_version):
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for document_page in document_version.pages.all():
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cls.process_document_page(document_page=document_page)
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class OCRBackendBase(object):
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def process_document_version(self, document_version):
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logger.info('Starting OCR for document version: %s', document_version)
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logger.debug('document version: %d', document_version.pk)
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for document_page in document_version.pages.all():
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self.process_document_page(document_page=document_page)
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def process_document_page(self, document_page):
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logger.info(
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'Processing page: %d of document version: %s',
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document_page.page_number, document_page.document_version
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)
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image = document_page.get_image()
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try:
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document_page_content, created = DocumentPageContent.on_organization.get_or_create(
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document_page=document_page
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)
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document_page_content.content = self.execute(
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file_object=image, language=document_page.document.language
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)
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document_page_content.save()
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finally:
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image.close()
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logger.info(
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'Finished processing page: %d of document version: %s',
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document_page.page_number, document_page.document_version
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)
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def execute(self, file_object, language=None, transformations=None):
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self.language = language
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if not transformations:
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transformations = []
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self.converter = converter_class(file_object=file_object)
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for transformation in transformations:
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self.converter.transform(transformation=transformation)
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