WIP: email sending crate

crates/email/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "mas-email"
+version = "0.1.0"
+authors = ["Quentin Gliech <quenting@element.io>"]
+edition = "2021"
+license = "Apache-2.0"
+
+[dependencies]
+tokio = { version = "1.15.0", features = ["macros"] }
+
+mas-templates = { path = "../templates" }
+anyhow = "1.0.52"
+async-trait = "0.1.52"
+
+[dependencies.lettre]
+version = "0.10.0-rc.4"
+default-features = false
+features = ["tokio1-rustls-tls", "hostname", "builder", "tracing", "pool"]

crates/email/src/lib.rs

@@ -0,0 +1,78 @@
+// Copyright 2022 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use lettre::{
+    message::{Mailbox, MessageBuilder, MultiPart},
+    AsyncTransport, Message,
+};
+use mas_templates::{EmailVerificationContext, Templates};
+
+pub struct Mailer {
+    templates: Templates,
+    from: Mailbox,
+    reply_to: Mailbox,
+}
+
+impl Mailer {
+    pub fn new<T>(templates: &Templates, from: Mailbox, reply_to: Mailbox) -> Self {
+        Self {
+            templates: templates.clone(),
+            from,
+            reply_to,
+        }
+    }
+
+    fn base_message(&self) -> MessageBuilder {
+        Message::builder()
+            .from(self.from.clone())
+            .reply_to(self.reply_to.clone())
+    }
+
+    async fn prepare_verification_email(
+        &self,
+        to: Mailbox,
+        context: &EmailVerificationContext,
+    ) -> anyhow::Result<Message> {
+        let plain = self
+            .templates
+            .render_email_verification_txt(context)
+            .await?;
+
+        let html = self
+            .templates
+            .render_email_verification_html(context)
+            .await?;
+
+        let multipart = MultiPart::alternative_plain_html(plain, html);
+
+        let message = self.base_message().to(to).multipart(multipart)?;
+
+        Ok(message)
+    }
+
+    pub async fn send_verification_email<T>(
+        &self,
+        transport: &T,
+        to: Mailbox,
+        context: &EmailVerificationContext,
+    ) -> anyhow::Result<()>
+    where
+        T: AsyncTransport + Send + Sync,
+        T::Error: std::error::Error + Send + Sync + 'static,
+    {
+        let message = self.prepare_verification_email(to, context).await?;
+        transport.send(message).await?;
+        Ok(())
+    }
+}