zip package for epub/pdf/audiobooks

[wolnelektury.git] / apps / catalogue / utils.py

diff --git a/apps/catalogue/utils.py b/apps/catalogue/utils.py
index 566eaf4..d5ef2b7 100644 (file)
--- a/apps/catalogue/utils.py
+++ b/apps/catalogue/utils.py
@@ -2,6 +2,8 @@
 # This file is part of Wolnelektury, licensed under GNU Affero GPLv3 or later.
 # Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information.
 #
+from __future__ import with_statement
+
 import random
 import time
 from base64 import urlsafe_b64encode
@@ -9,6 +11,13 @@ from base64 import urlsafe_b64encode
 from django.core.files.uploadedfile import UploadedFile
 from django.utils.hashcompat import sha_constructor
 from django.conf import settings
+from celery.task import task
+from os import mkdir, path, unlink
+from errno import EEXIST
+from fcntl import flock, LOCK_EX
+from zipfile import ZipFile
+
+from librarian import DocProvider
 
 
 # Use the system (hardware-based) random number generator if it exists.
@@ -44,3 +53,63 @@ class ExistingFile(UploadedFile):
 
     def close(self):
         pass
+
+
+class BookImportDocProvider(DocProvider):
+    """Used for joined EPUB and PDF files."""
+
+    def __init__(self, book):
+        self.book = book
+
+    def by_slug(self, slug):
+        if slug == self.book.slug:
+            return self.book.xml_file
+        else:
+            return type(self.book).objects.get(slug=slug).xml_file
+
+
+class LockFile(object):
+    def __init__(self, dir, objname):
+        self.lockname = path.join(dir, objname + ".lock")
+
+    def __entry__(self):
+        self.lock = open(self.lockname, 'w')
+        flock(self.lock, LOCK_EX)
+
+    def __exit__(self, *err):
+        self.lock.close()
+        unlink(self.lockname)
+
+
+def create_zip(paths, zip_slug):
+    # directory to store zip files
+    zip_path = path.join(settings.MEDIA_ROOT, 'zip')
+
+    try:
+        mkdir(zip_path)
+    except OSError as oe:
+        if oe.errno != EEXIST:
+            raise oe
+    zip_filename = zip_slug + ".zip"
+
+    with LockFile(zip_path, zip_slug):
+        if not path.exists(path.join(zip_path, zip_filename)):
+            with ZipFile(path.join(zip_path, zip_filename), 'w') as zipf:
+                for p in paths:
+                    zipf.write(p, path.basename(p))
+
+        return 'zip/' + zip_filename
+
+
+def remove_zip(zip_slug):
+    zip_file = path.join(settings.MEDIA_ROOT, 'zip', zip_slug + '.zip')
+    try:
+        unlink(zip_file)
+    except OSError as oe:
+        if oe.errno != EEXIST:
+            raise oe
+
+
+@task
+def create_zip_task(*args):
+    return create_zip(*args)