added pdfcredential native support

modoboa/pdfcredentials/lib.py

@@ -0,0 +1,101 @@
+"""Internal library."""
+
+from io import BytesIO
+import os
+import struct
+
+from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
+from cryptography.hazmat.backends import default_backend
+
+from django.conf import settings
+from django.utils.encoding import force_bytes, smart_bytes
+from django.utils.translation import ugettext as _
+
+from modoboa.lib.exceptions import InternalError
+from modoboa.parameters import tools as param_tools
+
+
+def init_storage_dir():
+    """Create the directory whare documents will be stored."""
+    storage_dir = param_tools.get_global_parameter("storage_dir")
+    if os.path.exists(storage_dir):
+        return
+    try:
+        os.mkdir(storage_dir)
+    except (OSError, IOError) as inst:
+        raise InternalError(
+            _("Failed to create the directory that will contain "
+              "PDF documents (%s)") % inst
+        )
+
+
+def get_creds_filename(account):
+    """Return the full path of a document."""
+    storage_dir = param_tools.get_global_parameter("storage_dir")
+    return os.path.join(storage_dir, account.username + ".pdf")
+
+
+def delete_credentials(account):
+    """Try to delete a local file."""
+    fname = get_creds_filename(account)
+    if not os.path.exists(fname):
+        return
+    os.remove(fname)
+
+
+def _get_cipher(iv):
+    """Return ready-to-user Cipher."""
+    key = smart_bytes(settings.SECRET_KEY[:32])
+    backend = default_backend()
+    return Cipher(
+        algorithms.AES(force_bytes(key)),
+        modes.CBC(iv),
+        backend=backend
+    )
+
+
+def crypt_and_save_to_file(content, filename, length, chunksize=64*512):
+    """Crypt content and save it to a file."""
+    iv = os.urandom(16)
+    cipher = _get_cipher(iv)
+    encryptor = cipher.encryptor()
+    with open(filename, "wb") as fp:
+        fp.write(struct.pack(b"<Q", length))
+        fp.write(iv)
+        while True:
+            chunk = content.read(chunksize)
+            if not len(chunk):
+                break
+            elif len(chunk) % 16:
+                chunk += b" " * (16 - len(chunk) % 16)
+            fp.write(encryptor.update(force_bytes(chunk)))
+        fp.write(encryptor.finalize())
+
+
+def decrypt_file(filename, chunksize=24*1024):
+    """Decrypt the content of a file and return it."""
+    buff = BytesIO()
+    with open(filename, "rb") as fp:
+        origsize = struct.unpack(b"<Q", fp.read(struct.calcsize(b"Q")))[0]
+        iv = fp.read(16)
+        cipher = _get_cipher(iv)
+        decryptor = cipher.decryptor()
+        while True:
+            chunk = fp.read(chunksize)
+            if not len(chunk):
+                break
+            buff.write(decryptor.update(chunk))
+        buff.write(decryptor.finalize())
+        buff.truncate(origsize)
+    return buff.getvalue()
+
+
+def get_document_logo():
+    """Retrieve path to logo."""
+    try:
+        logo = settings.MODOBOA_CUSTOM_LOGO
+        logo = os.path.join(settings.MEDIA_ROOT, os.path.basename(logo))
+    except AttributeError:
+        logo = os.path.join(settings.STATIC_ROOT, "css/modoboa.png")
+    finally:
+        return logo