new option: --output-filename

Author: srittau

README.md

@@ -16,5 +16,6 @@ Usage
 
 Supported options:
 
-  * `-b, --bind [ADDRESS]` IP addresses to listen on, defaults to 127.0.0.1
-  * `-p, --port [PORT]` SMTP port to listen on
+  * `-o`, `--output-filename [FILENAME]` mbox file for output, default: stdout
+  * `-b`, `--bind [ADDRESS]` IP addresses to listen on, default: 127.0.0.1
+  * `-p`, `--port [PORT]` SMTP port to listen on

fakesmtpd/args.py

@@ -1,11 +1,14 @@
 import argparse
 from smtplib import SMTP_PORT
-from typing import List, Any
+from typing import Any
 
 
-def parse_args(argv: List[str]) -> Any:
+def parse_args() -> Any:
     parser = argparse.ArgumentParser(
         description="SMTP server for testing mail functionality")
+    parser.add_argument(
+        "--output-filename", "-o", nargs="?", default="-",
+        help="output mbox file, default stdout")
     parser.add_argument(
         "--bind", "-b", nargs="?", default="127.0.0.1",
         help="IP address range to listen to")

fakesmtpd/mbox.py

@@ -1,8 +1,18 @@
+import sys
+
 from fakesmtpd.state import State
 
 
-def print_mbox_mail(stream, state: State) -> None:
+def print_mbox_mail(filename: str, state: State) -> None:
     """Print a mail in RFC 4155 default mbox format."""
+    if filename == "-":
+        write_mbox_mail(sys.stdout, state)
+    else:
+        with open(filename, "a") as f:
+            write_mbox_mail(f, state)
+
+
+def write_mbox_mail(stream, state) -> None:
     stream.write(f"From {state.reverse_path} {state.date.ctime()}\n")
     for receiver in state.forward_path:
         stream.write(f"X-FakeSMTPd-Receiver: {receiver}\n")

fakesmtpd/server.py

@@ -14,24 +14,24 @@
 
 def main() -> None:
     logging.basicConfig(level=logging.INFO)
-    args = parse_args(sys.argv)
+    args = parse_args()
+    printer = partial(print_mbox_mail, args.output_filename)
     try:
-        run_server(args.bind, args.port)
+        run_server(args.bind, args.port, partial(handle_connection, printer))
     except PermissionError as exc:
         print(str(exc), file=sys.stderr)
         sys.exit(1)
 
 
-def run_server(host: Optional[str], port: int) -> None:
+def run_server(host: Optional[str], port: int, handler) -> None:
     loop = asyncio.get_event_loop()
     loop.add_signal_handler(signal.SIGINT, loop.stop)
     loop.add_signal_handler(signal.SIGTERM, loop.stop)
-    s = asyncio.start_server(handle_connection, host=host, port=port)
+    s = asyncio.start_server(handler, host=host, port=port)
     loop.run_until_complete(s)
     loop.run_forever()
 
 
-async def handle_connection(reader: StreamReader, writer: StreamWriter) \
-        -> None:
-    print_it = partial(print_mbox_mail, sys.stdout)
-    await ConnectionHandler(reader, writer, print_it).handle()
+async def handle_connection(
+        printer, reader: StreamReader, writer: StreamWriter) -> None:
+    await ConnectionHandler(reader, writer, printer).handle()

fakesmtpd_test/mbox.py

@@ -4,11 +4,11 @@
 from io import StringIO
 from unittest import TestCase
 
-from fakesmtpd.mbox import print_mbox_mail
+from fakesmtpd.mbox import write_mbox_mail
 from fakesmtpd.state import State
 
 
-class PrintMboxMailTest(TestCase):
+class WriteMboxMailTest(TestCase):
 
     def test_print(self):
         out = StringIO()
@@ -17,7 +17,7 @@ def test_print(self):
         state.reverse_path = "sender@example.com"
         state.forward_path = ["receiver1@example.com", "receiver2@example.com"]
         state.mail_data = "Subject: Foo\r\n\r\nText\r\n"
-        print_mbox_mail(out, state)
+        write_mbox_mail(out, state)
         assert_equal("From sender@example.com Sun Jun  4 14:34:15 2017\n"
                      "X-FakeSMTPd-Receiver: receiver1@example.com\n"
                      "X-FakeSMTPd-Receiver: receiver2@example.com\n"