prototype for an interface to sendmail

sendmail.py

@@ -0,0 +1,66 @@
+import getpass
+import subprocess
+from email.mime.text import MIMEText
+
+
+OUTPUT_DIVIDER = "The message was:"
+OUTPUT_DIVIDER_BAR = "=" * len(OUTPUT_DIVIDER)
+
+
+class SendMailMessage:
+
+    def __init__(self, to_addr, from_addr=None, subject=None, body=None):
+        self.to_addr = to_addr
+        self.from_addr = from_addr
+        self.subject = subject
+        self.body = body
+
+    def send(self):
+        msg = self.encode()
+        sendmail(msg)
+
+
+    def encode(self, *args, **kwargs):
+        from_addr = self.from_addr
+        if from_addr is None:
+            from_addr = getpass.getuser()
+
+        body = self.body
+        if body is None: # here, None does not work!
+            body = ""
+
+        msg = MIMEText(body)
+        msg["To"] = self.to_addr
+        msg["From"] = from_addr
+        msg["Subject"] = self.subject
+        return msg.as_bytes(*args, **kwargs)
+
+
+
+def sendmail(msg):
+    cmd = ("sendmail", "-t", "-oi")
+    res = subprocess.run(cmd, input=msg, stderr=subprocess.PIPE)
+    try:
+        res.check_returncode()
+    except subprocess.CalledProcessError as e:
+        raise SendMailError(res.returncode, res.stderr, msg) from e
+
+
+
+class SendMailError(Exception):
+
+    def __init__(self, err_code, err_msg, email):
+        self.err_code = err_code
+        self.err_msg = err_msg = err_msg.decode().strip()
+        self.email = email = email.decode()
+        err = [
+            f"error code {err_code}: {err_msg}\n",
+            OUTPUT_DIVIDER,
+            OUTPUT_DIVIDER_BAR,
+            email
+        ]
+        err = "\n".join(err)
+        super().__init__(err)
+
+
+