better S/MIME detection, HELO FQDN

.github/workflows/run-unittest.yml

@@ -5,7 +5,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.7, 3.8, 3.9, "3.10", 3.11]
+        python-version: ["3.10", 3.11, 3.12]
     steps:
       - uses: actions/checkout@v2
       - name: Set up Python ${{ matrix.python-version }}
@@ -17,7 +17,7 @@ jobs:
           python -m pip install --upgrade pip
           pip install M2Crypto
           pip install -e .
-      - name: Run tests      
+      - name: Run tests
         run: python3 tests.py
       # As we support both python-magic and file-magic, try them one by one.
       - name: Test python-magic
@@ -26,7 +26,7 @@ jobs:
         run: pip uninstall python-magic -y
       - name: Test libmagic missing
         id: should_fail
-        run: python3 tests.py TestMime.test_libmagic        
+        run: python3 tests.py TestMime.test_libmagic
         continue-on-error: true
       - name: Check on failures
         if: steps.should_fail.outcome != 'failure'

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## 2.0.3
 - fix: loading headers not encoded with utf-8
+- fix: better S/MIME detection #29
+- drop Python 3.9 support
+- SMTP HELO FQDN
 
 ## 2.0.2 (2022-11-25)
 - experimental [XARF](http://xarf.org/) reports reading

README.md

@@ -307,18 +307,19 @@ Envelope().attach(path="file.jpg")
     * **.date(date)** `str|False` Specify Date header (otherwise Date is added automatically). If False, the Date header will not be added automatically.
   * **smtp**: SMTP server
     * **--smtp**
-    * **.smtp(host="localhost", port=25, user=, password=, security=, timeout=3, attempts=3, delay=3)**
+    * **.smtp(host="localhost", port=25, user=, password=, security=, timeout=3, attempts=3, delay=3, local_hostname=None)**
     * **Envelope(smtp=)**
     * Parameters:
         * `host` May include hostname or any of the following input formats (ex: path to an INI file or a `dict`)
         * `security` If not set, automatically set to `starttls` for port *587* and to `tls` for port *465*
         * `timeout` How many seconds should SMTP wait before timing out.
         * `attempts` How many times we try to send the message to an SMTP server.
         * `delay` How many seconds to sleep before re-trying a timed out connection.
+        * `local_hostname` FQDN of the local host in the HELO/EHLO command.
     * Input format may be in the following form:
         * `None` default localhost server used
-        * `smtplib.SMTP` object
-        * `list` or `tuple` having `host, [port, [username, password, [security, [timeout, [attempts, [delay]]]]]]` parameters
+        * standard [`smtplib.SMTP`](https://docs.python.org/3/library/smtplib.html) object
+        * `list` or `tuple` having `host, [port, [username, password, [security, [timeout, [attempts, [delay, [local_hostname]]]]]]]` parameters
             * ex: `envelope --smtp localhost 125 [email protected]` will set up host, port and username parameters
         * `dict` specifying {"host": ..., "port": ...}
             * ex: `envelope --smtp '{"host": "localhost"}'` will set up host parameter
@@ -330,7 +331,7 @@ Envelope().attach(path="file.jpg")
             ```
     * Do not fear to pass the `smtp` in a loop, we make just a single connection to the server. If timed out, we attempt to reconnect once.
     ```python3
-    smtp = localhost, 25
+    smtp = "localhost", 25
     for mail in mails:
         Envelope(...).smtp(smtp).send()
     ```

envelope/__main__.py

@@ -136,7 +136,7 @@ def main():
                             metavar="SUBTYPE")
     group_send.add_argument('--smtp',
                             help="SMTP server. List `host, [port, [username, password,"
-                                 " [security, [timeout, [attempts, [delay]]]]]]` or dict.\n"
+                                 " [security, [timeout, [attempts, [delay, [local_hostname]]]]]]]` or dict.\n"
                                  "Ex: '--smtp {\"host\": \"localhost\", \"port\": 25}'."
                                  " Security may be explicitly set to 'starttls', 'tls'"
                                  " or automatically determined by port.",

envelope/envelope.py

@@ -32,7 +32,7 @@
 from .message import _Message
 from .parser import Parser
 from .smtp_handler import SMTPHandler
-from .utils import AutoSubmittedHeader, is_gpg_importable_key, assure_list, assure_fetched, get_mimetype
+from .utils import AutoSubmittedHeader, Fetched, is_gpg_importable_key, assure_list, assure_fetched, get_mimetype
 
 __doc__ = """Quick layer over python-gnupg, M2Crypto, smtplib, magic and email handling packages.
 Their common use cases merged into a single function. Want to sign a text and tired of forgetting how to do it right?
@@ -705,7 +705,7 @@ def header(self, key, val=None, replace=False) -> Union["Envelope", list, str, N
         return self
 
     def smtp(self, host: Any = "localhost", port=25, user=None, password=None, security=None, timeout=3, attempts=3,
-             delay=3):
+             delay=3, local_hostname=None):
         """
         Obtain SMTP server connection.
         Note that you may safely call this in a loop,
@@ -718,6 +718,7 @@ def smtp(self, host: Any = "localhost", port=25, user=None, password=None, secur
         :param timeout: How many seconds should SMTP wait before timing out.
         :param attempts: How many times we try to send the message to an SMTP server.
         :param delay: How many seconds to sleep before re-trying a timed out connection.
+        :param local_hostname: FQDN of the local host in the HELO/EHLO command.
         :return:
         """
         # CLI interface returns always a list or dict, ex: host=["localhost"] or host=["ini file"] or host={}
@@ -753,7 +754,7 @@ def smtp(self, host: Any = "localhost", port=25, user=None, password=None, secur
             self._smtp = SMTPHandler(host)
         else:
             self._smtp = SMTPHandler(host, port, user, password, security, timeout=timeout, attempts=attempts,
-                                     delay=delay)
+                                     delay=delay, local_hostname=local_hostname)
         return self
 
     def attach(self, attachment=None, mimetype=None, name=None, inline=None, *, path=None):
@@ -1001,7 +1002,7 @@ def _start(self, sign=None, encrypt=None, send=None):
 
         return email
 
-    def _determine_gpg(self, encrypt, sign):
+    def _determine_gpg(self, encrypt: Fetched | list[Fetched], sign: Fetched):
         """ determine if we are using gpg or smime"""
         gpg_on = None
         if encrypt or sign:
@@ -1047,8 +1048,7 @@ def _determine_gpg(self, encrypt, sign):
                                 raise RuntimeError("No GPG sign key found")
                     elif is_gpg_importable_key(sign):
                         # sign is Path or key contents, import it and get its fingerprint
-                        result = self._gnupg.import_keys(assure_fetched(sign, bytes))
-                        sign = result.fingerprints[0]
+                        sign = self._gpg_import_or_fail(sign)[0]
 
                 if encrypt:
                     if encrypt == AUTO:
@@ -1064,13 +1064,25 @@ def _determine_gpg(self, encrypt, sign):
                         decipherers = []
                         for item in assure_list(encrypt):
                             if is_gpg_importable_key(item):
-                                decipherers.extend(self._gnupg.import_keys(assure_fetched(item, bytes)).fingerprints)
+                                decipherers.extend(self._gpg_import_or_fail(item))
                             else:
                                 decipherers.append(item)
                         encrypt = decipherers
 
         return encrypt, sign, gpg_on
 
+    def _gpg_import_or_fail(self, key):
+        """
+        :param key: Any attainable contents
+        :raises ValueError: If import failed
+        :return: Fingerprints
+        """
+        if imported := self._gnupg.import_keys(assure_fetched(key, bytes)):
+            return imported.fingerprints
+        else:
+            raise ValueError(f"Could not import key starting: {key[:80]}...")
+
+
     def _get_gnupg_home(self, for_help=False):
         s = self._gpg if type(self._gpg) is str else None
         if for_help:

envelope/smtp_handler.py

@@ -14,7 +14,7 @@ class SMTPHandler:
     _instances: Dict[str, SMTP] = {}
 
     def __init__(self, host="localhost", port=25, user=None, password=None, security=None, timeout=3, attempts=3,
-                 delay=3):
+                 delay=3, local_hostname=None):
         self.attempts = attempts
         # If sending timeouts, delay N seconds before another attempt.
         self.delay = delay
@@ -29,6 +29,7 @@ def __init__(self, host="localhost", port=25, user=None, password=None, security
             self.password = password
             self.security = security
             self.timeout = timeout
+            self.local_hostname = local_hostname
         d = locals()
         del d["self"]
         self.key = repr(d)
@@ -43,10 +44,10 @@ def connect(self):
 
             context = ssl.create_default_context()
             if self.security == "tls":
-                smtp = SMTP_SSL(self.host, self.port,
+                smtp = SMTP_SSL(self.host, self.port, self.local_hostname,
                                 timeout=self.timeout, context=context)
             else:
-                smtp = SMTP(self.host, self.port, timeout=self.timeout)
+                smtp = SMTP(self.host, self.port, self.local_hostname, timeout=self.timeout)
                 if self.security == "starttls":
                     smtp.starttls(context=context)
             if self.user:

envelope/utils.py

@@ -9,6 +9,7 @@
     from .envelope import Envelope
 
 logger = logging.getLogger(__name__)
+Fetched = str | bytes | None
 
 
 class AutoSubmittedHeader:
@@ -76,7 +77,7 @@ def assure_list(v):
     return [v]
 
 
-def assure_fetched(message, retyped=None):
+def assure_fetched(message, retyped=None) -> Fetched:
     """ Accepts object, returns its string or bytes.
     If object is
         * str or bytes, we consider this is the file contents

setup.py

@@ -42,5 +42,5 @@
     classifiers=[
         'Programming Language :: Python :: 3'
     ],
-    python_requires='>=3.7',
+    python_requires='>=3.10',
 )

tests.py

@@ -1522,7 +1522,7 @@ def quit(self):
 
         def key(name):
             return "{'host': '" + name + "', 'port': 25, 'user': None, 'password': None," \
-                                         " 'security': None, 'timeout': 3, 'attempts': 3, 'delay': 3}"
+                                         " 'security': None, 'timeout': 3, 'attempts': 3, 'delay': 3, 'local_hostname': None}"
 
         SMTPHandler._instances={key(name): DummySMTPConnection(name) for name in (f"dummy{i}" for i in range(4))}