SMTP error refactoring

src/smtp/send.rs

@@ -0,0 +1,64 @@
+//! # SMTP message sending
+
+use super::Smtp;
+use lettre::*;
+
+use crate::context::Context;
+use crate::events::Event;
+
+pub type Result<T> = std::result::Result<T, Error>;
+
+#[derive(Debug, Fail)]
+pub enum Error {
+    #[fail(display = "Envelope error: {}", _0)]
+    EnvelopeError(#[cause] lettre::error::Error),
+    #[fail(display = "Send error: {}", _0)]
+    SendError(#[cause] lettre::smtp::error::Error),
+    #[fail(display = "SMTP has no transport")]
+    NoTransport,
+}
+
+impl Smtp {
+    /// Send a prepared mail to recipients.
+    /// On successful send out Ok() is returned.
+    pub fn send(
+        &mut self,
+        context: &Context,
+        recipients: Vec<EmailAddress>,
+        message: Vec<u8>,
+        job_id: u32,
+    ) -> Result<()> {
+        let message_len = message.len();
+
+        let recipients_display = recipients
+            .iter()
+            .map(|x| format!("{}", x))
+            .collect::<Vec<String>>()
+            .join(",");
+
+        if let Some(ref mut transport) = self.transport {
+            let envelope =
+                Envelope::new(self.from.clone(), recipients).map_err(Error::EnvelopeError)?;
+            let mail = SendableEmail::new(
+                envelope,
+                format!("{}", job_id), // only used for internal logging
+                message,
+            );
+
+            transport.send(mail).map_err(Error::SendError)?;
+
+            context.call_cb(Event::SmtpMessageSent(format!(
+                "Message len={} was smtp-sent to {}",
+                message_len, recipients_display
+            )));
+            self.transport_connected = true;
+            Ok(())
+        } else {
+            warn!(
+                context,
+                "uh? SMTP has no transport, failed to send to {}", recipients_display
+            );
+            return Err(Error::NoTransport);
+        }
+    }
+}