Add proof of concept compressed document storage backend

mayan/apps/storage/backends/compressedstorage.py

@@ -0,0 +1,51 @@
+from __future__ import absolute_import
+
+import os
+import zipfile
+
+try:
+    import zlib
+    COMPRESSION = zipfile.ZIP_DEFLATED
+except:
+    COMPRESSION = zipfile.ZIP_STORED
+
+try:
+    from cStringIO import StringIO
+except ImportError:
+    from StringIO import StringIO
+
+from django.core.files import File
+from django.core.files.storage import FileSystemStorage
+
+from ..conf.settings import FILESTORAGE_LOCATION
+
+
+class CompressedStorage(FileSystemStorage):
+    """Simple wrapper for the stock Django FileSystemStorage class"""
+
+    separator = os.path.sep
+
+    def __init__(self, *args, **kwargs):
+        super(CompressedStorage, self).__init__(*args, **kwargs)
+        self.location = FILESTORAGE_LOCATION
+
+    def save(self, name, content):
+        descriptor = StringIO()
+        zf = zipfile.ZipFile(descriptor, mode='w', compression=COMPRESSION)
+
+        zf.writestr('document', content.read())
+
+        for file in zf.filelist:
+            file.create_system = 0
+
+        zf.close()
+        descriptor.seek(0)
+        return super(CompressedStorage, self).save(name, File(descriptor))
+
+    def open(self, name, mode='rb'):
+        storage_file = super(CompressedStorage, self).open(name, mode)
+        zf = zipfile.ZipFile(storage_file)
+        descriptor = StringIO()
+        descriptor.write(zf.read('document'))
+        descriptor.seek(0)
+        return File(descriptor)