1 files changed, 56 insertions, 0 deletions
diff --git a/gn_auth/smtp.py b/gn_auth/smtp.py
new file mode 100644
index 0000000..42d8eae
--- /dev/null
+++ b/gn_auth/smtp.py
@@ -0,0 +1,56 @@
+"""Handle sending emails. Uses Python3's `smtplib`."""
+import smtplib
+import mimetypes
+from typing import Optional
+from email.message import EmailMessage
+from email.headerregistry import Address
+
+
+def __read_mime__(filepath) -> dict:
+    """Read mimetype for attachments"""
+    _mime,_extras = mimetypes.guess_type(filepath)
+    if bool(_mime):
+        return dict(zip(("maintype", "subtype"),
+                        _mime.split("/")))# type: ignore[union-attr]
+    return {}
+
+
+def build_email_message(# pylint: disable=[too-many-arguments]
+        to_addresses: tuple[Address, ...],
+        subject: str,
+        txtmessage: str,
+        htmlmessage: str = "",
+        attachments: tuple[str, ...] = tuple(),
+        from_address: Address = Address(
+            "GeneNetwork Automated Emails", "no-reply", "genenetwork.org")
+) -> EmailMessage:
+    """Build an email message."""
+    msg = EmailMessage()
+    msg["From"] = from_address
+    msg["To"] = to_addresses
+    msg["Subject"] = subject
+    msg.set_content(txtmessage)
+    if bool(htmlmessage):
+        msg.add_alternative(htmlmessage, subtype="html")
+    for _path in attachments:
+        with open(_path, "rb") as _file:
+            msg.add_attachment(_file.read(), **__read_mime__(_path))
+
+    return msg
+
+
+def send_message(# pylint: disable=[too-many-arguments]
+        smtp_user: str,
+        smtp_passwd: str,
+        message: EmailMessage,
+        host: str = "",
+        port: int = 587,
+        local_hostname: Optional[str]=None,
+        timeout: int = 200,
+        source_address: Optional[tuple[tuple[str, int], ...]] = None
+):
+    """Set up a connection to a SMTP server and send a message."""
+    with smtplib.SMTP(host, port, local_hostname, timeout, source_address) as conn:
+        conn.starttls()
+        conn.login(smtp_user, smtp_passwd)
+        conn.send_message(message)