End of chapter.

src/domain/subscriber_email.rs

@@ -19,6 +19,12 @@ impl AsRef<str> for SubscriberEmail {
     }
 }
 
+impl std::fmt::Display for SubscriberEmail {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::SubscriberEmail;

src/email_client.rs

@@ -24,7 +24,7 @@ impl EmailClient {
 
     pub async fn send_email(
         &self,
-        recipient: SubscriberEmail,
+        recipient: &SubscriberEmail,
         subject: &str,
         html_content: &str,
         text_content: &str,
@@ -124,7 +124,7 @@ mod tests {
 
         // Act
         let _ = email_client
-            .send_email(email(), &subject(), &content(), &content())
+            .send_email(&email(), &subject(), &content(), &content())
             .await;
 
         // Assert
@@ -144,7 +144,7 @@ mod tests {
 
         // Act
         let outcome = email_client
-            .send_email(email(), &subject(), &content(), &content())
+            .send_email(&email(), &subject(), &content(), &content())
             .await;
 
         // Assert
@@ -166,7 +166,7 @@ mod tests {
 
         // Act
         let outcome = email_client
-            .send_email(email(), &subject(), &content(), &content())
+            .send_email(&email(), &subject(), &content(), &content())
             .await;
 
         // Assert
@@ -188,7 +188,7 @@ mod tests {
 
         // Act
         let outcome = email_client
-            .send_email(email(), &subject(), &content(), &content())
+            .send_email(&email(), &subject(), &content(), &content())
             .await;
 
         // Assert

src/routes/newsletters.rs

@@ -45,15 +45,28 @@ pub async fn publish_newsletter(
 ) -> Result<HttpResponse, PublishError> {
     let subscribers = get_confirmed_subscribers(&pool).await?;
     for subscriber in subscribers {
+        match subscriber {
+            Ok(subscriber) => {
                 email_client
                     .send_email(
-                subscriber.email,
+                        &subscriber.email,
                         &body.title,
                         &body.content.html,
                         &body.content.text,
                     )
                     .await
-            .with_context(|| format!("Failed to send newsletter issue to {}", subscriber.email))?;
+                    .with_context(|| {
+                        format!("Failed to send newsletter issue to {}", subscriber.email)
+                    })?;
+            }
+            Err(error) => {
+                tracing::warn!(
+                    error.cause_chain = ?error,
+                    "Skipping a confirmed subscriber. \
+                    Their stored contact details are invalid",
+                );
+            }
+        }
     }
     Ok(HttpResponse::Ok().finish())
 }
@@ -65,7 +78,7 @@ struct ConfirmedSubscriber {
 #[tracing::instrument(name = "Adding a new subscriber", skip(pool))]
 async fn get_confirmed_subscribers(
     pool: &PgPool,
-) -> Result<Vec<ConfirmedSubscriber>, anyhow::Error> {
+) -> Result<Vec<Result<ConfirmedSubscriber, anyhow::Error>>, anyhow::Error> {
     struct Row {
         email: String,
     }
@@ -82,8 +95,9 @@ async fn get_confirmed_subscribers(
     .await?;
     let confirmed_subscribers = rows
         .into_iter()
-        .map(|r| ConfirmedSubscriber {
-            email: SubscriberEmail::parse(r.email).unwrap(),
+        .map(|r| match SubscriberEmail::parse(r.email) {
+            Ok(email) => Ok(ConfirmedSubscriber { email }),
+            Err(error) => Err(anyhow::anyhow!(error)),
         })
         .collect();
     Ok(confirmed_subscribers)

src/routes/subscriptions.rs

@@ -122,7 +122,7 @@ pub async fn send_confirmation_email(
         confirmation_link
     );
     email_client
-        .send_email(new_subscriber.email, "Welcome!", &html_body, &plain_body)
+        .send_email(&new_subscriber.email, "Welcome!", &html_body, &plain_body)
         .await
 }