python bindings: import example

* Added an example script for importing a key from a file (either
  ASCII armoured or not).

lang/python/examples/howto/import-key.py

@@ -0,0 +1,91 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+from __future__ import absolute_import, division, unicode_literals
+
+# Copyright (C) 2018 Ben McGinnes <ben@gnupg.org>
+#
+# 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 os.path
+import sys
+
+print("""
+This script exports one or more public keys.
+""")
+
+c = gpg.Context(armor=True)
+
+if len(sys.argv) >= 3:
+    keyfile = sys.argv[1]
+    homedir = sys.argv[2]
+elif len(sys.argv) == 2:
+    keyfile = sys.argv[1]
+    homedir = input("Enter the GPG configuration directory path (optional): ")
+else:
+    keyfile = input("Enter the path and filename to import the key(s) from: ")
+    homedir = input("Enter the GPG configuration directory path (optional): ")
+
+if homedir.startswith("~"):
+    if os.path.exists(os.path.expanduser(homedir)) is True:
+        c.home_dir = os.path.expanduser(homedir)
+    else:
+        pass
+elif os.path.exists(homedir) is True:
+    c.home_dir = homedir
+else:
+    pass
+
+if os.path.isfile(keyfile) is True:
+    with open(keyfile, "rb") as f:
+        incoming = f.read()
+    result = c.key_import(incoming)
+else:
+    result = None
+
+if result is not None and hasattr(result, "considered") is False:
+    print(result)
+elif result is not None and hasattr(result, "considered") is True:
+    num_keys = len(result.imports)
+    new_revs = result.new_revocations
+    new_sigs = result.new_signatures
+    new_subs = result.new_sub_keys
+    new_uids = result.new_user_ids
+    new_scrt = result.secret_imported
+    nochange = result.unchanged
+    print("""
+The total number of keys considered for import was:  {0}
+
+   Number of keys revoked:  {1}
+ Number of new signatures:  {2}
+    Number of new subkeys:  {3}
+   Number of new user IDs:  {4}
+Number of new secret keys:  {5}
+ Number of unchanged keys:  {6}
+
+The key IDs for all considered keys were:
+""".format(num_keys, new_revs, new_sigs, new_subs, new_uids, new_scrt,
+           nochange))
+    for i in range(num_keys):
+        print(result.imports[i].fpr)
+    print("")
+elif result is None:
+    print("You must specify a key file to import.")