fff-backup.patch

Index: calibre-plugin/jobs.py
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- calibre-plugin/jobs.py	(revision e2f2b5ed8c29347e36daa1d5f416568ced55daeb)
+++ calibre-plugin/jobs.py	(revision )
@@ -3,6 +3,13 @@
 from __future__ import (unicode_literals, division, absolute_import,
                         print_function)
 
+import os
+import tempfile
+
+import shutil
+
+import uuid
+
 __license__   = 'GPL v3'
 __copyright__ = '2017, Jim Miller, 2011, Grant Drake <grant.drake@gmail.com>'
 __docformat__ = 'restructuredtext en'
@@ -11,7 +18,7 @@
 logger = logging.getLogger(__name__)
 
 import traceback
-from datetime import time
+from datetime import time, datetime
 from StringIO import StringIO
 
 from calibre.utils.ipc.server import Server
@@ -221,7 +228,32 @@
 
                 logger.info("write to %s"%outfile)
                 inject_cal_cols(book,story,configuration)
-                writer.writeStory(outfilename=outfile, forceOverwrite=True)
+
+                # Copy original story to a temporary directory before attempting to write an updated version, since the
+                # story is fetched in writer.writeStory() and might raise an error; In that case we don't have to create
+                # the backup since the original file remains unchanged. The outfile path is guaranteed to exist since we
+                # are updating the story
+                temp_path = tempfile.mkdtemp()
+                original_path = os.path.join(temp_path, os.path.basename(outfile))
+                shutil.copy(outfile, original_path)
+
+                try:
+                    writer.writeStory(outfilename=outfile, forceOverwrite=True)
+                except Exception:
+                    # Make sure to remove the temporary directory and let the exception bubble up
+                    shutil.rmtree(temp_path, ignore_errors=True)
+                    raise
+
+                # Use date for easy visual differentiation and a random UUID to make sure (however unlikely) that we
+                # don't overwrite a previous backup of the story if it was updated within the same minute according
+                # to the running system
+                backup_destination = os.path.join('/', 'home', 'user', 'Documents')
+                backup_filename = '%s.%s_%s' % (
+                    writer.getOutputFileName(), datetime.now().strftime('%d_%m_%Y_%H_%M'), uuid.uuid4().hex
+                )
+                backup_path = os.path.join(backup_destination, backup_filename)
+                shutil.move(original_path, backup_path)
+                shutil.rmtree(temp_path, ignore_errors=True)
 
                 book['comment'] = _('Download %s completed, %s chapters.')%(options['fileform'],story.getMetadata("numChapters"))
                 book['all_metadata'] = story.getAllMetadata(removeallentities=True)
@@ -269,7 +301,32 @@
                 logger.info("write to %s"%outfile)
 
                 inject_cal_cols(book,story,configuration)
-                writer.writeStory(outfilename=outfile, forceOverwrite=True)
+
+                # Copy original story to a temporary directory before attempting to write an updated version, since the
+                # story is fetched in writer.writeStory() and might raise an error; In that case we don't have to create
+                # the backup since the original file remains unchanged. The outfile path is guaranteed to exist since we
+                # are updating the story
+                temp_path = tempfile.mkdtemp()
+                original_path = os.path.join(temp_path, os.path.basename(outfile))
+                shutil.copy(outfile, original_path)
+
+                try:
+                    writer.writeStory(outfilename=outfile, forceOverwrite=True)
+                except Exception:
+                    # Make sure to remove the temporary directory and let the exception bubble up
+                    shutil.rmtree(temp_path, ignore_errors=True)
+                    raise
+
+                # Use date for easy visual differentiation and a random UUID to make sure (however unlikely) that we
+                # don't overwrite a previous backup of the story if it was updated within the same minute according
+                # to the running system
+                backup_destination = os.path.join('/', 'home', 'user', 'Documents')
+                backup_filename = '%s.%s_%s' % (
+                    writer.getOutputFileName(), datetime.now().strftime('%d_%m_%Y_%H_%M'), uuid.uuid4().hex
+                )
+                backup_path = os.path.join(backup_destination, backup_filename)
+                shutil.move(original_path, backup_path)
+                shutil.rmtree(temp_path, ignore_errors=True)
 
                 book['comment'] = _('Update %s completed, added %s chapters for %s total.')%\
                     (options['fileform'],(urlchaptercount-chaptercount),urlchaptercount)