cleanup email a bit

src/email.rs

@@ -3,11 +3,38 @@ use crate::server_config::EmailConfig;
 use crate::template;
 use crate::util::SerializableUrl;
 use handlebars::Handlebars;
-use lettre::message::header::{Header, HeaderName, HeaderValue};
+use lettre::message::header::{Header, HeaderName, HeaderValue, UserAgent};
 use lettre::message::{Mailbox, SinglePart};
 use lettre::{Address, AsyncTransport};
 use log::warn;
 
+#[derive(Clone, Debug)]
+struct AutoGeneratedHeader(String);
+
+impl Default for AutoGeneratedHeader {
+    fn default() -> Self {
+        Self("auto-generated".into())
+    }
+}
+
+impl Header for AutoGeneratedHeader {
+    fn name() -> HeaderName {
+        HeaderName::new_from_ascii_str("Auto-Submitted")
+    }
+
+    fn parse(s: &str) -> Result<Self, Box<dyn std::error::Error + Send + Sync>> {
+        Ok(Self(s.into()))
+    }
+
+    fn display(&self) -> HeaderValue {
+        HeaderValue::new(Self::name(), self.0.clone())
+    }
+}
+
+fn user_agent() -> UserAgent {
+    String::from("fs-infmath-jobboerse via sendmail").into()
+}
+
 #[derive(serde::Serialize)]
 pub(crate) struct EmailData {
     pub(crate) confirmation_link: SerializableUrl,
@@ -19,50 +46,28 @@ pub(crate) async fn send_confirmation_email(
     email_config: &EmailConfig,
     email_data: &EmailData,
 ) -> actix_web::Result<(), EmailError> {
+    // receiver of the confirmation e-mail
     let to_mailbox = Mailbox::new(None, contact_address);
 
     let email_body = hb.render(template::EMAIL_PLAIN, &email_data)?;
 
-    #[derive(Clone, Debug)]
-    struct AutoGeneratedHeader(String);
-
-    impl Default for AutoGeneratedHeader {
-        fn default() -> Self {
-            Self("auto-generated".into())
-        }
-    }
-
-    impl Header for AutoGeneratedHeader {
-        fn name() -> HeaderName {
-            HeaderName::new_from_ascii_str("Auto-Submitted")
-        }
-
-        fn parse(s: &str) -> Result<Self, Box<dyn std::error::Error + Send + Sync>> {
-            Ok(Self(s.into()))
-        }
-
-        fn display(&self) -> HeaderValue {
-            HeaderValue::new(Self::name(), self.0.clone())
-        }
-    }
-
-    let ua_header =
-        lettre::message::header::UserAgent::from(String::from("fs-infmath-jobboerse via sendmail"));
-
     let message = lettre::Message::builder()
         .from(email_config.from.to_owned())
         .to(to_mailbox)
         .subject(&email_config.subject)
-        .header(ua_header.clone())
+        .header(user_agent())
         .header(AutoGeneratedHeader::default())
         .singlepart(SinglePart::plain(email_body))?;
+
     lettre::AsyncSendmailTransport::new().send(message).await?;
 
+    // successfully send a confirmation e-mail now send a notice to our-self
+
     let message = lettre::Message::builder()
         .from(email_config.from.to_owned())
         .to(email_config.from.to_owned())
         .subject(&email_config.subject)
-        .header(ua_header)
+        .header(user_agent())
         .header(AutoGeneratedHeader::default())
         .singlepart(SinglePart::plain(
             "Automatischer Hinweis: Eine neue Stellenausschreibung wurde zur Jobbörse eingereicht!"