Unsubscribe link in emails sent

src/templates.rs

@@ -63,8 +63,25 @@ pub struct NewPostEmailTemplate<'a> {
     pub post_excerpt: &'a str,
 }
 
-impl<'a> NewPostEmailTemplate<'a> {
-    pub fn text_version(&self) -> String {
+#[derive(Template)]
+#[template(path = "../templates/email/standalone.html")]
+pub struct StandaloneEmailTemplate<'a> {
+    pub base_url: &'a str,
+    pub html_content: &'a str,
+    pub text_content: &'a str,
+}
+
+pub trait EmailTemplate: Sync {
+    fn html(&self) -> String;
+    fn text(&self) -> String;
+}
+
+impl<'a> EmailTemplate for NewPostEmailTemplate<'a> {
+    fn html(&self) -> String {
+        self.render().unwrap()
+    }
+
+    fn text(&self) -> String {
         format!(
             r#"New post available!
 
@@ -86,10 +103,31 @@ Alphonse
 
 zero2prod - Building better backends with Rust
 Visit the blog: {}
-Unsubscribe: {}/unsubscribe
+Unsubscribe: {}/unsubscribe?token=UNSUBSCRIBE_TOKEN
 
 You're receiving this because you subscribed to the zero2prod newsletter."#,
             self.post_title, self.base_url, self.post_id, self.base_url, self.base_url,
         )
     }
 }
+
+impl<'a> EmailTemplate for StandaloneEmailTemplate<'a> {
+    fn html(&self) -> String {
+        self.render().unwrap()
+    }
+
+    fn text(&self) -> String {
+        format!(
+            r#"{}
+
+---
+
+zero2prod - Building better backends with Rust
+Visit the blog: {}
+Unsubscribe: {}/unsubscribe?token=UNSUBSCRIBE_TOKEN
+
+You're receiving this because you subscribed to the zero2prod newsletter."#,
+            self.text_content, self.base_url, self.base_url
+        )
+    }
+}