feat: direct email notification endpoint

apps/labrinth/src/database/models/notification_item.rs

@@ -129,12 +129,11 @@ impl NotificationBuilder {
         Ok(())
     }
 
-    pub async fn insert_many(
+    async fn insert_many_records(
         &self,
-        users: Vec<DBUserId>,
+        users: &[DBUserId],
         transaction: &mut PgTransaction<'_>,
-        redis: &RedisPool,
-    ) -> Result<(), DatabaseError> {
+    ) -> Result<Vec<i64>, DatabaseError> {
         let notification_ids =
             generate_many_notification_ids(users.len(), &mut *transaction)
                 .await?;
@@ -163,6 +162,20 @@ impl NotificationBuilder {
         .execute(&mut *transaction)
         .await?;
 
+        Ok(notification_ids)
+    }
+
+    pub async fn insert_many(
+        &self,
+        users: Vec<DBUserId>,
+        transaction: &mut PgTransaction<'_>,
+        redis: &RedisPool,
+    ) -> Result<(), DatabaseError> {
+        let notification_ids =
+            self.insert_many_records(&users, transaction).await?;
+
+        let users_raw_ids = users.iter().map(|x| x.0).collect::<Vec<_>>();
+
         let notification_types = notification_ids
             .iter()
             .map(|_| self.body.notification_type().as_str())
@@ -181,6 +194,19 @@ impl NotificationBuilder {
         Ok(())
     }
 
+    /// Like [`insert_many`], but skips queuing deliveries so the caller can
+    /// manually send the notifications.
+    pub async fn insert_many_without_delivery(
+        &self,
+        users: Vec<DBUserId>,
+        transaction: &mut PgTransaction<'_>,
+        redis: &RedisPool,
+    ) -> Result<(), DatabaseError> {
+        self.insert_many_records(&users, transaction).await?;
+        DBNotification::clear_user_notifications_cache(&users, redis).await?;
+        Ok(())
+    }
+
     pub async fn insert_many_deliveries(
         transaction: &mut PgTransaction<'_>,
         redis: &RedisPool,

apps/labrinth/src/routes/internal/external_notifications.rs

@@ -5,19 +5,28 @@ use crate::database::models::notification_item::NotificationBuilder;
 use crate::database::models::user_item::DBUser;
 use crate::database::redis::RedisPool;
 use crate::models::users::Role;
-use crate::models::v3::notifications::NotificationBody;
+use crate::models::v3::notifications::{
+    NotificationBody, NotificationDeliveryStatus,
+};
 use crate::models::v3::pats::Scopes;
+use crate::queue::email::EmailQueue;
 use crate::queue::session::AuthQueue;
 use crate::routes::ApiError;
 use crate::util::guards::external_notification_key_guard;
-use actix_web::HttpRequest;
+use actix_web::http::StatusCode;
 use actix_web::web;
-use actix_web::{HttpResponse, post};
+use actix_web::{
+    CustomizeResponder, HttpRequest, HttpResponse, Responder, post,
+};
 use ariadne::ids::UserId;
+use eyre::eyre;
+use lettre::message::Mailbox;
 use serde::Deserialize;
 
 pub fn config(cfg: &mut web::ServiceConfig) {
-    cfg.service(create).service(send_custom_email);
+    cfg.service(create)
+        .service(create_direct_email)
+        .service(send_custom_email);
 }
 
 #[derive(Deserialize)]
@@ -56,6 +65,99 @@ pub async fn create(
     Ok(HttpResponse::Accepted().finish())
 }
 
+/// Directly sends emails to users and inserts notifications when emails are
+/// delivered successfully.
+///
+/// Responds with the user IDs that could not be emailed:
+/// - `200` if every recipient was delivered (empty list)
+/// - `207` if some recipients failed (list of failed IDs)
+/// - `500` if no recipient was delivered
+#[post(
+    "external_notifications/direct-email",
+    guard = "external_notification_key_guard"
+)]
+pub async fn create_direct_email(
+    pool: web::Data<PgPool>,
+    redis: web::Data<RedisPool>,
+    email_queue: web::Data<EmailQueue>,
+    create_notification: web::Json<CreateNotification>,
+) -> Result<CustomizeResponder<web::Json<Vec<UserId>>>, ApiError> {
+    let CreateNotification { body, user_ids } =
+        create_notification.into_inner();
+    let user_ids = user_ids
+        .into_iter()
+        .map(|x| DBUserId(x.0 as i64))
+        .collect::<Vec<_>>();
+
+    let mut txn = pool.begin().await?;
+
+    if !DBUser::exists_many(&user_ids, &mut txn).await? {
+        return Err(ApiError::InvalidInput(
+            "One of the specified users do not exist.".to_owned(),
+        ));
+    }
+
+    let mut results: Vec<Result<DBUserId, DBUserId>> =
+        Vec::with_capacity(user_ids.len());
+
+    for user_id in &user_ids {
+        let user = DBUser::get_id(*user_id, &mut txn, &redis).await?.ok_or(
+            ApiError::Internal(eyre!(
+                "user `{}` disappeared while sending notification email",
+                user_id.0
+            )),
+        )?;
+
+        let delivered =
+            match user.email.and_then(|email| email.parse::<Mailbox>().ok()) {
+                Some(mailbox) => {
+                    email_queue
+                        .send_one(&mut txn, body.clone(), *user_id, mailbox)
+                        .await?
+                        == NotificationDeliveryStatus::Delivered
+                }
+                None => false,
+            };
+
+        results.push(if delivered {
+            Ok(*user_id)
+        } else {
+            Err(*user_id)
+        });
+    }
+
+    let delivered = results
+        .iter()
+        .filter_map(|result| result.as_ref().ok().copied())
+        .collect::<Vec<_>>();
+
+    if delivered.is_empty() {
+        return Err(ApiError::Internal(eyre!(
+            "failed to deliver notification email to any of {} recipients",
+            user_ids.len(),
+        )));
+    }
+
+    NotificationBuilder { body }
+        .insert_many_without_delivery(delivered, &mut txn, &redis)
+        .await?;
+
+    txn.commit().await?;
+
+    let failed = results
+        .into_iter()
+        .filter_map(|result| result.err().map(|id| UserId(id.0 as u64)))
+        .collect::<Vec<_>>();
+
+    let status = if failed.is_empty() {
+        StatusCode::OK
+    } else {
+        StatusCode::MULTI_STATUS
+    };
+
+    Ok(web::Json(failed).customize().with_status(status))
+}
+
 #[derive(Deserialize)]
 struct SendEmail {
     pub users: Vec<UserId>,