models/email: Extract NewEmail::insert_if_missing() fn

Author: Turbo87

src/models/email.rs

@@ -1,4 +1,6 @@
 use chrono::NaiveDateTime;
+use diesel::{OptionalExtension, QueryResult};
+use diesel_async::{AsyncPgConnection, RunQueryDsl};
 use secrecy::SecretString;
 
 use crate::models::User;
@@ -23,3 +25,21 @@ pub struct NewEmail<'a> {
     pub email: &'a str,
     pub verified: bool,
 }
+
+impl NewEmail<'_> {
+    /// Inserts the email into the database and returns the confirmation token,
+    /// or does nothing if it already exists and returns `None`.
+    pub async fn insert_if_missing(
+        &self,
+        conn: &mut AsyncPgConnection,
+    ) -> QueryResult<Option<SecretString>> {
+        diesel::insert_into(emails::table)
+            .values(self)
+            .on_conflict_do_nothing()
+            .returning(emails::token)
+            .get_result::<String>(conn)
+            .await
+            .map(Into::into)
+            .optional()
+    }
+}

src/models/user.rs

@@ -2,7 +2,6 @@ use chrono::NaiveDateTime;
 use diesel::prelude::*;
 use diesel_async::scoped_futures::ScopedFutureExt;
 use diesel_async::{AsyncConnection, AsyncPgConnection, RunQueryDsl};
-use secrecy::SecretString;
 
 use crate::app::App;
 use crate::controllers::user::update::UserConfirmEmail;
@@ -177,16 +176,7 @@ impl<'a> NewUser<'a> {
                         verified: false,
                     };
 
-                    let token = insert_into(emails::table)
-                        .values(&new_email)
-                        .on_conflict_do_nothing()
-                        .returning(emails::token)
-                        .get_result::<String>(conn)
-                        .await
-                        .optional()?
-                        .map(SecretString::from);
-
-                    if let Some(token) = token {
+                    if let Some(token) = new_email.insert_if_missing(conn).await? {
                         // Swallows any error. Some users might insert an invalid email address here.
                         let email = UserConfirmEmail {
                             user_name: &user.gh_login,