Text parsers and OCR backends are now used in tandem for each document.

mayan/apps/ocr/classes.py

@@ -2,13 +2,47 @@ from __future__ import unicode_literals
 
 import logging
 
+from django.utils.module_loading import import_string
+
 from converter import converter_class
 
+from .exceptions import NoMIMETypeMatch, ParserError
 from .models import DocumentPageContent
+from .parsers import Parser
+from .settings import setting_ocr_backend
 
 logger = logging.getLogger(__name__)
 
 
+class TextExtractor(object):
+    @classmethod
+    def perform_ocr(cls, document_page):
+        ocr_backend_class = import_string(setting_ocr_backend.value)
+        backend = ocr_backend_class()
+        backend.process_document_page(document_page)
+
+    @classmethod
+    def process_document_page(cls, document_page):
+        """
+        Extract text for a document version's page. Try parsing the page and if
+        no there are not parsers for the MIME type or the parser return nothing
+        fallback to doing and OCR of the page.
+        """
+
+        try:
+            Parser.parse_document_page(document_page=document_page)
+        except (NoMIMETypeMatch, ParserError):
+            cls.perform_ocr(document_page=document_page)
+        else:
+            if not document_page.ocr_content.content:
+                cls.perform_ocr(document_page=document_page)
+
+    @classmethod
+    def process_document_version(cls, document_version):
+        for document_page in document_version.pages.all():
+            cls.process_document_page(document_page=document_page)
+
+
 class OCRBackendBase(object):
     def process_document_version(self, document_version):
         logger.info('Starting OCR for document version: %s', document_version)
@@ -17,9 +51,9 @@ class OCRBackendBase(object):
         language = document_version.document.language
 
         for document_page in document_version.pages.all():
-            self.process_document_page(document_page=document_page, language=language)
+            self.process_document_page(document_page=document_page)
 
-    def process_document_page(self, document_page, language=None):
+    def process_document_page(self, document_page):
             logger.info(
                 'Processing page: %d of document version: %s',
                 document_page.page_number, document_page.document_version
@@ -32,7 +66,7 @@ class OCRBackendBase(object):
                     document_page=document_page
                 )
                 document_page_content.content = self.execute(
-                    file_object=image, language=language
+                    file_object=image, language=document_page.document.language
                 )
                 document_page_content.save()
             finally: