examples: python howto

* Uses the groups module to prepare a list of recipients and encrypt
  to those.
* The main version (encrypt-to-group.py) tries to check for invalid
  recipients, but still falls back to always trust for the second
  encryption attempt.
* The gullible version doesn't try pruning the recipient list at all,
  it just tries to encrypt and if it fails, switches straight to
  always trust.
* The trustno1 version doesn't use the always trust model at all and
  only attempts pruning the list of invalid recipients.

1 files changed, 91 insertions, 0 deletions

diff --git a/lang/python/examples/howto/encrypt-to-group.py b/lang/python/examples/howto/encrypt-to-group.py
new file mode 100755
index 00000000..84f8d103
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+++ b/lang/python/examples/howto/encrypt-to-group.py
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+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+from __future__ import absolute_import, division, unicode_literals
+
+# Copyright (C) 2018 Ben McGinnes <[email protected]>
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free Software
+# Foundation; either version 2 of the License, or (at your option) any later
+# version.
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU Lesser General Public License as published by the Free
+# Software Foundation; either version 2.1 of the License, or (at your option)
+# any later version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU General Public License and the GNU
+# Lesser General Public Licensefor more details.
+#
+# You should have received a copy of the GNU General Public License and the GNU
+# Lesser General Public along with this program; if not, see
+# <http://www.gnu.org/licenses/>.
+
+import gpg
+import sys
+from groups import group_lists
+
+"""
+Uses the groups module to encrypt to multiple recipients.
+
+"""
+
+c = gpg.Context(armor=True)
+
+if len(sys.argv) > 3:
+    group_id = sys.argv[1]
+    filepath = sys.argv[2:]
+elif len(sys.argv) == 3:
+    group_id = sys.argv[1]
+    filepath = sys.argv[2]
+elif len(sys.argv) == 2:
+    group_id = sys.argv[1]
+    filepath = input("Enter the filename to encrypt: ")
+else:
+    group_id = input("Enter the group name to encrypt to: ")
+    filepath = input("Enter the filename to encrypt: ")
+
+with open(filepath, "rb") as f:
+    text = f.read()
+
+for i in range(len(group_lists)):
+    if group_lists[i][0] == group_id:
+        klist = group_lists[i][1]
+    else:
+        klist = None
+
+logrus = []
+
+if klist is not None:
+    for i in range(len(klist)):
+        apattern = list(c.keylist(pattern=klist[i], secret=False))
+        if apattern[0].can_encrypt == 1:
+            logrus.append(apattern[0])
+        else:
+            pass
+    try:
+        ciphertext, result, sign_result = c.encrypt(text, recipients=logrus,
+                                                    add_encrypt_to=True)
+    except gpg.errors.InvalidRecipients as e:
+        for i in range(len(e.recipients)):
+            for n in range(len(logrus)):
+                if logrus[n].fpr == e.recipients[i].fpr:
+                    logrus.remove(logrus[n])
+                else:
+                    pass
+        try:
+            ciphertext, result, sign_result = c.encrypt(text,
+                                                        recipients=logrus,
+                                                        add_encrypt_to=True,
+                                                        always_trust=True)
+        except:
+            pass
+    with open("{0}.asc".format(filepath), "wb") as f:
+              f.write(ciphertext)
+else:
+    pass
+
+# EOF