minor style fix

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

diff --git a/apps/catalogue/utils.py b/apps/catalogue/utils.py
index 368f96d..0fdeaf8 100644 (file)
--- a/apps/catalogue/utils.py
+++ b/apps/catalogue/utils.py
@@ -2,16 +2,28 @@
 # This file is part of Wolnelektury, licensed under GNU Affero GPLv3 or later.
 # Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information.
 #
 # 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
 
 import random
 import time
 from base64 import urlsafe_b64encode
 

+from django.http import HttpResponse, HttpResponseRedirect, Http404, HttpResponsePermanentRedirect

 from django.core.files.uploadedfile import UploadedFile
 from django.core.files.uploadedfile import UploadedFile

+from django.core.files.base import File
+from django.core.files.storage import DefaultStorage

 from django.utils.hashcompat import sha_constructor
 from django.conf import settings
 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, ENOENT
+from fcntl import flock, LOCK_EX
+from zipfile import ZipFile
+from traceback import print_exc

 
 

-from librarian import DocProvider
-
+from reporting.utils import read_chunks
+from celery.task import task
+import catalogue.models

 
 # Use the system (hardware-based) random number generator if it exists.
 if hasattr(random, 'SystemRandom'):
 
 # Use the system (hardware-based) random number generator if it exists.
 if hasattr(random, 'SystemRandom'):


@@ -48,14 +60,132 @@ class ExistingFile(UploadedFile):
         pass
 
 
         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):
+    """
+    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
+    """
+    try:
+        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."
+    except Exception, e:
+        print "Error during pdf creation: %s" % e
+        print_exc
+        raise e
+
+
+class MultiQuerySet(object):
+    def __init__(self, *args, **kwargs):
+        self.querysets = args
+        self._count = None
+    
+    def count(self):
+        if not self._count:
+            self._count = sum(len(qs) for qs in self.querysets)
+        return self._count
+    
+    def __len__(self):
+        return self.count()
+        
+    def __getitem__(self, item):
+        try:
+            indices = (offset, stop, step) = item.indices(self.count())
+        except AttributeError:
+            # it's not a slice - make it one
+            return self[item : item + 1][0]
+        items = []
+        total_len = stop - offset
+        for qs in self.querysets:
+            if len(qs) < offset:
+                offset -= len(qs)
+            else:
+                items += list(qs[offset:stop])
+                if len(items) >= total_len:
+                    return items
+                else:
+                    offset = 0
+                    stop = total_len - len(items)
+                    continue