add email

layercake/layercake/email_.py

@@ -0,0 +1,64 @@
+from email.mime.application import MIMEApplication
+from email.mime.multipart import MIMEMultipart
+from email.mime.text import MIMEText
+from email.utils import formataddr
+from pathlib import Path
+
+
+class Message:
+    def __init__(
+        self,
+        from_: tuple[str | None, str],
+        to: tuple[str | None, str],
+        subject: str,
+        reply_to: tuple[str | None, str] | None = None,
+        content: str | None = None,
+    ) -> None:
+        self._references = set()
+        self._body = MIMEMultipart('alternative')
+        self._message = MIMEMultipart('mixed')
+        self._message['From'] = formataddr(from_)
+        self._message['To'] = formataddr(to)
+        self._message['Subject'] = subject
+        self._message.attach(self._body)
+
+        if reply_to:
+            self._message['Reply-To'] = formataddr(reply_to)
+
+        if content:
+            self.add_alternative(content, subtype='plain')
+
+    def add_header(self, name: str, value: str) -> None:
+        self._message.add_header(name, value)
+
+    def add_in_reply_to(self, message_id: str) -> None:
+        self._message['In-Reply-To'] = message_id
+        self._references.add(message_id)  # Add to set avoids duplicates
+
+    def add_alternative(
+        self,
+        text: str,
+        /,
+        subtype: str = 'html',
+        charset: str = 'utf-8',
+    ) -> None:
+        self._body.attach(MIMEText(text, subtype, charset))
+
+    def attach(self, path: Path, filename: str | None = None) -> None:
+        if not path.is_file():
+            return None
+
+        with path.open('rb') as fp:
+            part = MIMEApplication(fp.read())
+            part.add_header(
+                'Content-Disposition',
+                'attachment',
+                filename=filename or path.name,
+            )
+            self._message.attach(part)
+
+    def as_bytes(self) -> bytes:
+        if self._references:
+            self._message['References'] = ' '.join(self._references)
+
+        return self._message.as_bytes()