+ return type(self.book).objects.get(
+ slug=slug, language=language).xml_file
+
+
+class LockFile(object):
+ """
+ A file lock monitor class; createas an ${objname}.lock
+ file in directory dir, and locks it exclusively.
+ To be used in 'with' construct.
+ """
+ def __init__(self, dir, objname):
+ self.lockname = path.join(dir, objname + ".lock")
+
+ def __enter__(self):
+ self.lock = open(self.lockname, 'w')
+ flock(self.lock, LOCK_EX)
+
+ def __exit__(self, *err):
+ try:
+ unlink(self.lockname)
+ except OSError as oe:
+ if oe.errno != oe.EEXIST:
+ raise oe
+ self.lock.close()
+
+
+@task
+def create_zip(paths, zip_slug):
+ """
+ Creates a zip in MEDIA_ROOT/zip directory containing files from path.
+ Resulting archive filename is ${zip_slug}.zip
+ Returns it's path relative to MEDIA_ROOT (no initial slash)
+ """
+ # 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)):
+ zipf = ZipFile(path.join(zip_path, zip_filename), 'w')
+ try:
+ for arcname, p in paths:
+ if arcname is None:
+ arcname = path.basename(p)
+ zipf.write(p, arcname)
+ finally:
+ zipf.close()
+
+ return 'zip/' + zip_filename
+
+
+def remove_zip(zip_slug):
+ """
+ removes the ${zip_slug}.zip file from zip store.
+ """
+ zip_file = path.join(settings.MEDIA_ROOT, 'zip', zip_slug + '.zip')
+ try:
+ unlink(zip_file)
+ except OSError as oe:
+ if oe.errno != ENOENT:
+ raise oe
+
+
+class AttachmentHttpResponse(HttpResponse):
+ """Response serving a file to be downloaded.
+ """
+ def __init__ (self, file_path, file_name, mimetype):
+ super(AttachmentHttpResponse, self).__init__(mimetype=mimetype)
+ self['Content-Disposition'] = 'attachment; filename=%s' % file_name
+ self.file_path = file_path
+ self.file_name = file_name
+
+ with open(DefaultStorage().path(self.file_path)) as f:
+ for chunk in read_chunks(f):
+ self.write(chunk)
+
+@task
+def async_build_pdf(book_id, customizations, file_name):
+ """
+ A celery task to generate pdf files.
+ Accepts the same args as Book.build_pdf, but with book id as first parameter
+ instead of Book instance
+ """
+ book = catalogue.models.Book.objects.get(id=book_id)
+ print "will gen %s" % DefaultStorage().path(file_name)
+ if not DefaultStorage().exists(file_name):
+ book.build_pdf(customizations=customizations, file_name=file_name)
+ print "done."