From fdfb0e65d3de718beddcf3c882d716b7aff6a051 Mon Sep 17 00:00:00 2001
From: Martin Ashby <martin@ashbysoft.com>
Date: Sat, 31 Dec 2022 16:30:52 +0000
Subject: Add email notifications to comments

---
 comments/src/main.rs | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 59 insertions(+), 1 deletion(-)

(limited to 'comments/src')

diff --git a/comments/src/main.rs b/comments/src/main.rs
index 2bc11fa..7064bca 100644
--- a/comments/src/main.rs
+++ b/comments/src/main.rs
@@ -15,6 +15,10 @@ use axum::{
     routing::get,
     Router,
 };
+use lettre::{
+    AsyncSmtpTransport, AsyncTransport, Message, Tokio1Executor,
+    transport::smtp::authentication::Credentials
+};
 use serde::Deserialize;
 use sqlx::{
     postgres::{PgPool, PgPoolOptions},
@@ -25,11 +29,20 @@ use sqlx::{
 };
 use std::{net::SocketAddr, time::Duration};
 
+
 // Useful global thingies
 #[derive(Clone)]
 struct Ctx {
     pool: PgPool,
     base_path: String,
+    mail_opts: Option<MailCtx>,
+}
+
+#[derive(Clone)]
+struct MailCtx {
+    notification_address: String,
+    smtp_server: String,
+    smtp_credentials: Credentials,
 }
 
 #[tokio::main]
@@ -40,6 +53,18 @@ async fn main() {
     let db_connection_str = std::env::var("DATABASE_URL")
         .unwrap_or_else(|_| "postgres://postgres:password@localhost".to_string());
 
+    let notification_address = std::env::var("NOTIFICATION_ADDRESS").ok();
+    let mail_opts = notification_address.map(|na| {
+        let smtp_server = std::env::var("SMTP_SERVER").expect("SMTP_SERVER  not supplied!");
+        let smtp_username = std::env::var("SMTP_USERNAME").expect("SMTP_USERNAME not supplied!");
+        let smtp_password = std::env::var("SMTP_PASSWORD").expect("SMTP_PASSWORD not supplied!");
+        MailCtx{
+            smtp_server: smtp_server,
+            smtp_credentials: Credentials::new(smtp_username, smtp_password),
+            notification_address: na,
+        }
+    });
+
     let pool = PgPoolOptions::new()
         .max_connections(5)
         .connect_timeout(Duration::from_secs(3))
@@ -51,7 +76,7 @@ async fn main() {
         .await
         .expect("failed to run migrations");
     
-    let ctx = Ctx {pool, base_path: base_path.clone()};
+    let ctx = Ctx {pool, base_path: base_path.clone(), mail_opts};
 
     let app = Router::new()
         .nest(&base_path, Router::new()
@@ -142,6 +167,14 @@ struct CapchaAnswer {
     answer:String
 }
 
+#[derive(Template)]
+#[template(path = "notification.txt")]
+struct Notification<'a> {
+    url: &'a str,
+    comment: &'a str,
+    author: &'a str,
+}
+
 async fn post_comments(
     State(ctx): State<Ctx>,
     Form(post_comment): Form<PostComment>) -> Result<Redirect,(StatusCode,String)> {
@@ -158,6 +191,31 @@ async fn post_comments(
         .execute(&ctx.pool)
         .await
         .map_err(internal_error)?;
+
+    if let Some(mail_opts) = ctx.mail_opts {
+        let mail_body = Notification{
+            url: &post_comment.url,
+            author: &post_comment.author,
+            comment: &post_comment.comment
+        }.render().unwrap();
+        let email = Message::builder()
+            // TODO should be a config value
+            .from("Comments Service <comments@mfashby.net>".parse().unwrap())
+            .to(mail_opts.notification_address.parse().unwrap())
+            .subject(format!("New comment on {}", post_comment.url))
+            .body(mail_body)
+            .unwrap();
+        let mailer: AsyncSmtpTransport<Tokio1Executor> =
+            AsyncSmtpTransport::<Tokio1Executor>::relay(&mail_opts.smtp_server)
+                .unwrap()
+                .credentials(mail_opts.smtp_credentials)
+                .build();
+        match mailer.send(email).await {
+            Ok(_) => (),
+            Err(e) => eprintln!("Could not send email: {:?}", e),
+        }
+    };
+    
     Ok(Redirect::temporary(&post_comment.url))
 }
 
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