first commit

src/mailer.rs

@@ -0,0 +1,86 @@
+use lettre::{
+    AsyncSmtpTransport, AsyncTransport, Message, Tokio1Executor,
+    message::Mailbox,
+    transport::smtp::{authentication::Credentials, extension::ClientId},
+};
+
+use crate::{
+    config::AppConfig,
+    error::{AppError, AppResult},
+};
+
+fn transport(config: &AppConfig) -> AppResult<AsyncSmtpTransport<Tokio1Executor>> {
+    let smtp = &config.smtp;
+    let mut builder = match smtp.kind.as_str() {
+        "starttls" => AsyncSmtpTransport::<Tokio1Executor>::starttls_relay(&smtp.host)
+            .map_err(|e| AppError::Mail(e.to_string()))?,
+        "tls" => AsyncSmtpTransport::<Tokio1Executor>::relay(&smtp.host)
+            .map_err(|e| AppError::Mail(e.to_string()))?,
+        _ => AsyncSmtpTransport::<Tokio1Executor>::builder_dangerous(&smtp.host),
+    }
+    .port(smtp.port);
+
+    if !smtp.client_name.trim().is_empty() {
+        builder = builder.hello_name(ClientId::Domain(smtp.client_name.trim().to_string()));
+    }
+    if !smtp.username.is_empty() {
+        builder = builder.credentials(Credentials::new(
+            smtp.username.clone(),
+            smtp.password.clone(),
+        ));
+    }
+    Ok(builder.build())
+}
+
+pub fn sender_named(
+    config: &AppConfig,
+    fallback: &str,
+    display_name: Option<&str>,
+) -> AppResult<Mailbox> {
+    let address = if config.smtp.admin_email.is_empty() {
+        fallback
+    } else {
+        &config.smtp.admin_email
+    };
+    let parsed = address
+        .parse()
+        .map_err(|e| AppError::bad_request(format!("invalid sender address: {e}")))?;
+    let name = display_name
+        .filter(|value| !value.trim().is_empty())
+        .unwrap_or(&config.smtp.admin_name);
+    Ok(Mailbox::new(Some(name.to_string()), parsed))
+}
+
+pub async fn send_text(
+    config: &AppConfig,
+    from_fallback: &str,
+    to: &str,
+    subject: &str,
+    body: &str,
+) -> AppResult<()> {
+    send_text_named(config, from_fallback, None, to, subject, body).await
+}
+
+pub async fn send_text_named(
+    config: &AppConfig,
+    from_fallback: &str,
+    from_name: Option<&str>,
+    to: &str,
+    subject: &str,
+    body: &str,
+) -> AppResult<()> {
+    let to: Mailbox = to
+        .parse()
+        .map_err(|e| AppError::bad_request(format!("invalid recipient: {e}")))?;
+    let message = Message::builder()
+        .from(sender_named(config, from_fallback, from_name)?)
+        .to(to)
+        .subject(subject)
+        .body(body.to_owned())
+        .map_err(|e| AppError::Mail(e.to_string()))?;
+    transport(config)?
+        .send(message)
+        .await
+        .map_err(|e| AppError::Mail(e.to_string()))?;
+    Ok(())
+}