chore: build out the nsend newsletter endpoint

Author: Utilitycoder

src/domain/subscriber_email.rs

@@ -18,6 +18,14 @@ impl AsRef<str> for SubscriberEmail {
     }
 }
 
+impl std::fmt::Display for SubscriberEmail {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        // We just forward to the Display implementation of
+        // the wrapped String.
+        self.0.fmt(f)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

src/email_client.rs

@@ -30,7 +30,7 @@ impl EmailClient {
 impl EmailClient {
     pub async fn send_email(
         &self,
-        recipient: SubscriberEmail,
+        recipient: &SubscriberEmail,
         subject: &str,
         html_content: &str,
         text_content: &str,
@@ -141,7 +141,7 @@ mod tests {
 
         let _ = email_client
             .send_email(
-                recipient,
+                &recipient,
                 &generate_subject(),
                 &generate_content(),
                 &generate_content(),
@@ -164,7 +164,7 @@ mod tests {
 
         let outcome = email_client
             .send_email(
-                subscriber_email,
+                &subscriber_email,
                 &generate_subject(),
                 &generate_content(),
                 &generate_content(),
@@ -189,7 +189,7 @@ mod tests {
 
         let outcome = email_client
             .send_email(
-                subscriber_email,
+                &subscriber_email,
                 &generate_subject(),
                 &generate_content(),
                 &generate_content(),
@@ -216,7 +216,7 @@ mod tests {
 
         let outcome = email_client
             .send_email(
-                subscriber_email,
+                &subscriber_email,
                 &generate_subject(),
                 &generate_content(),
                 &generate_content(),

src/routes/newsletters.rs

@@ -1,17 +1,88 @@
-use actix_web::{web, HttpResponse};
+use crate::{domain::SubscriberEmail, email_client::EmailClient, routes::error_chain_fmt};
+use actix_web::http::StatusCode;
+use actix_web::{web, HttpResponse, ResponseError};
+use anyhow::Context;
+use sqlx::PgPool;
 
 #[derive(serde::Deserialize)]
 pub struct BodyData {
     title: String,
     content: Content,
 }
 
+struct ConfirmedSubscriber {
+    email: SubscriberEmail,
+}
+
+#[tracing::instrument(name = "Get confirmed subscribers", skip(pool))]
+async fn get_confirmed_subscribers(
+    pool: &PgPool,
+) -> Result<Vec<Result<ConfirmedSubscriber, anyhow::Error>>, anyhow::Error> {
+    let confirmed_subscriber =
+        sqlx::query!(r#"SELECT email FROM subscriptions WHERE status = 'confirmed'"#,)
+            .fetch_all(pool)
+            .await?
+            .into_iter()
+            .map(|r| match SubscriberEmail::parse(r.email) {
+                Ok(email) => Ok(ConfirmedSubscriber { email }),
+                Err(error) => Err(anyhow::anyhow!(error)),
+            })
+            .collect();
+    Ok(confirmed_subscriber)
+}
+
 #[derive(serde::Deserialize)]
 pub struct Content {
     text: String,
     html: String,
 }
 
-pub async fn publish_newsletter(_body: web::Json<BodyData>) -> HttpResponse {
-    HttpResponse::Ok().finish()
+#[derive(thiserror::Error)]
+pub enum PublishError {
+    #[error(transparent)]
+    UnexpectedError(#[from] anyhow::Error),
+}
+
+impl ResponseError for PublishError {
+    fn status_code(&self) -> StatusCode {
+        match self {
+            PublishError::UnexpectedError(_) => StatusCode::INTERNAL_SERVER_ERROR,
+        }
+    }
+}
+
+impl std::fmt::Debug for PublishError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        error_chain_fmt(self, f)
+    }
+}
+
+pub async fn publish_newsletter(
+    body: web::Json<BodyData>,
+    pool: web::Data<PgPool>,
+    email_client: web::Data<EmailClient>,
+) -> Result<HttpResponse, PublishError> {
+    let subscribers = get_confirmed_subscribers(&pool).await?;
+    for subscriber in subscribers {
+        match subscriber {
+            Ok(subscriber) => {
+                email_client
+                    .send_email(
+                        &subscriber.email,
+                        &body.title,
+                        &body.content.text,
+                        &body.content.html,
+                    )
+                    .await
+                    .with_context(|| {
+                        format!("Failed to send newsletter issue to {}", subscriber.email)
+                    })?;
+            }
+
+            Err(error) => {
+                tracing::warn!("Skipping invalid subscriber: {}", error);
+            }
+        }
+    }
+    Ok(HttpResponse::Ok().finish())
 }

src/routes/subscriptions.rs

@@ -136,7 +136,7 @@ pub async fn send_confirmation_email(
 
     email_client
         .send_email(
-            new_subscriber.email,
+            &new_subscriber.email,
             "Welcome!",
             &html_body_text,
             &plain_body_text,