Basic unsubscribe endpoint

src/routes.rs

@@ -5,6 +5,7 @@ mod login;
 mod posts;
 mod subscriptions;
 mod subscriptions_confirm;
+mod unsubscribe;
 
 pub use admin::*;
 use askama::Template;
@@ -16,15 +17,38 @@ pub use health_check::*;
 pub use home::*;
 pub use login::*;
 pub use posts::*;
+use rand::{Rng, distr::Alphanumeric};
 use reqwest::StatusCode;
 pub use subscriptions::*;
 pub use subscriptions_confirm::*;
+pub use unsubscribe::*;
 
 use crate::{
     authentication::AuthError,
     templates::{InternalErrorTemplate, MessageTemplate, NotFoundTemplate},
 };
 
+pub fn generate_token() -> String {
+    let mut rng = rand::rng();
+    std::iter::repeat_with(|| rng.sample(Alphanumeric))
+        .map(char::from)
+        .take(25)
+        .collect()
+}
+
+fn error_chain_fmt(e: &impl std::error::Error, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+    writeln!(f, "{}", e)?;
+    let mut current = e.source();
+    while let Some(cause) = current {
+        write!(f, "Caused by:\n\t{}", cause)?;
+        current = cause.source();
+        if current.is_some() {
+            writeln!(f)?;
+        }
+    }
+    Ok(())
+}
+
 #[derive(thiserror::Error)]
 pub enum AppError {
     #[error("An unexpected error was encountered.")]

src/routes/subscriptions.rs

@@ -1,7 +1,7 @@
 use crate::{
     domain::{NewSubscriber, SubscriberEmail},
     email_client::EmailClient,
-    routes::AppError,
+    routes::{AppError, generate_token},
     startup::AppState,
     templates::MessageTemplate,
 };
@@ -13,35 +13,10 @@ use axum::{
     response::{Html, IntoResponse, Response},
 };
 use chrono::Utc;
-use rand::{Rng, distr::Alphanumeric};
 use serde::Deserialize;
 use sqlx::{Executor, Postgres, Transaction};
 use uuid::Uuid;
 
-fn generate_subscription_token() -> String {
-    let mut rng = rand::rng();
-    std::iter::repeat_with(|| rng.sample(Alphanumeric))
-        .map(char::from)
-        .take(25)
-        .collect()
-}
-
-pub fn error_chain_fmt(
-    e: &impl std::error::Error,
-    f: &mut std::fmt::Formatter,
-) -> std::fmt::Result {
-    writeln!(f, "{}", e)?;
-    let mut current = e.source();
-    while let Some(cause) = current {
-        write!(f, "Caused by:\n\t{}", cause)?;
-        current = cause.source();
-        if current.is_some() {
-            writeln!(f)?;
-        }
-    }
-    Ok(())
-}
-
 #[tracing::instrument(
     name = "Adding a new subscriber",
     skip(connection_pool, email_client, base_url, form),
@@ -69,7 +44,7 @@ pub async fn subscribe(
     let subscriber_id = insert_subscriber(&mut transaction, &new_subscriber)
         .await
         .context("Failed to insert new subscriber in the database.")?;
-    let subscription_token = generate_subscription_token();
+    let subscription_token = generate_token();
     store_token(&mut transaction, &subscription_token, &subscriber_id)
         .await
         .context("Failed to store the confirmation token for a new subscriber.")?;

src/routes/subscriptions_confirm.rs

@@ -1,4 +1,4 @@
-use crate::{startup::AppState, templates::ConfirmTemplate};
+use crate::{routes::generate_token, startup::AppState, templates::ConfirmTemplate};
 use askama::Template;
 use axum::{
     extract::{Query, State},
@@ -44,7 +44,8 @@ async fn confirm_subscriber(
     subscriber_id: &Uuid,
 ) -> Result<(), sqlx::Error> {
     sqlx::query!(
-        "UPDATE subscriptions SET status = 'confirmed' WHERE id = $1",
+        "UPDATE subscriptions SET status = 'confirmed', unsubscribe_token = $1 WHERE id = $2",
+        generate_token(),
         subscriber_id
     )
     .execute(connection_pool)

src/routes/unsubscribe.rs

@@ -0,0 +1,36 @@
+use crate::{routes::AppError, startup::AppState, templates::UnsubscribeTemplate};
+use anyhow::Context;
+use askama::Template;
+use axum::{
+    extract::{Query, State},
+    response::{Html, IntoResponse, Response},
+};
+use reqwest::StatusCode;
+use sqlx::Executor;
+
+#[derive(serde::Deserialize)]
+pub struct UnsubQueryParams {
+    token: String,
+}
+
+pub async fn unsubscribe(
+    Query(UnsubQueryParams { token }): Query<UnsubQueryParams>,
+    State(AppState {
+        connection_pool, ..
+    }): State<AppState>,
+) -> Result<Response, AppError> {
+    let query = sqlx::query!(
+        "DELETE FROM subscriptions WHERE unsubscribe_token = $1",
+        token
+    );
+    let result = connection_pool
+        .execute(query)
+        .await
+        .context("Could not update subscriptions table.")?;
+
+    if result.rows_affected() == 0 {
+        Ok(StatusCode::NOT_FOUND.into_response())
+    } else {
+        Ok(Html(UnsubscribeTemplate.render().unwrap()).into_response())
+    }
+}

src/startup.rs

@@ -127,6 +127,7 @@ pub fn app(
         .route("/health_check", get(health_check))
         .route("/subscriptions", post(subscribe))
         .route("/subscriptions/confirm", get(confirm))
+        .route("/unsubscribe", get(unsubscribe))
         .route("/posts", get(list_posts))
         .route("/posts/{post_id}", get(see_post))
         .nest("/admin", admin_routes)

src/templates.rs

@@ -50,6 +50,10 @@ pub struct ConfirmTemplate;
 #[template(path = "../templates/404.html")]
 pub struct NotFoundTemplate;
 
+#[derive(Template)]
+#[template(path = "../templates/unsubscribe.html")]
+pub struct UnsubscribeTemplate;
+
 #[derive(Template)]
 #[template(path = "../templates/email/new_post.html")]
 pub struct NewPostEmailTemplate<'a> {