Initial commit to modernize staging file handling including preview generation

mayan/apps/sources/classes.py

@@ -0,0 +1,60 @@
+from __future__ import absolute_import
+
+import base64
+import errno
+import os
+
+from django.core.exceptions import ObjectDoesNotExist
+from django.core.files import File
+from django.core.files.storage import FileSystemStorage
+from django.utils.encoding import smart_str
+from django.utils.translation import ugettext
+
+from converter.api import convert, cache_cleanup
+from converter.literals import (DEFAULT_ZOOM_LEVEL, DEFAULT_ROTATION,
+    DEFAULT_PAGE_NUMBER, DEFAULT_FILE_FORMAT_MIMETYPE)
+from documents.conf.settings import DISPLAY_SIZE, THUMBNAIL_SIZE
+from mimetype.api import get_mimetype
+
+
+class StagingFile(object):
+    """
+    Simple class to extend the File class to add preview capabilities
+    files in a directory on a storage
+    """
+    def __init__(self, staging_folder, filename):
+        self.staging_folder = staging_folder
+        self.filename = filename
+
+    def __unicode__(self):
+        return unicode(self.filename)
+
+    def open(self):
+        return open(self.get_full_path(), mode='rb')
+        #return File(file=descriptor, name=filename)
+
+    def get_full_path(self):
+        return os.path.join(self.staging_folder.folder_path, self.filename)
+
+    def get_image(self, size, page, zoom, rotation, as_base64=True):
+        #return self.get_valid_image(size=size, transformations=transformations)
+        converted_file_path = convert(self.get_full_path(), size=size)#, cleanup_files=True)#, transformations=transformations)
+
+        if as_base64:
+            mimetype = get_mimetype(open(converted_file_path, 'r'), converted_file_path, mimetype_only=True)[0]
+            image = open(converted_file_path, 'r')
+            base64_data = base64.b64encode(image.read())
+            image.close()
+            return u'data:%s;base64,%s' % (mimetype, base64_data)
+        else:
+            return file_path
+
+    #def delete(self, preview_size, transformations):
+    #    cache_cleanup(self.filepath, size=preview_size, transformations=transformations)
+    #    try:
+    #        os.unlink(self.filepath)
+    #    except OSError, exc:
+    #        if exc.errno == errno.ENOENT:
+    #            pass
+    #        else:
+    #            raise Exception(ugettext(u'Unable to delete staging file: %s') % exc)