Unsubscribe option available on website

src/routes/unsubscribe.rs

@@ -1,23 +1,109 @@
 use crate::{
+    domain::SubscriberEmail,
+    email_client::EmailClient,
     routes::AppError,
     startup::AppState,
-    templates::{NotFoundTemplate, UnsubscribeTemplate},
+    templates::{
+        MessageTemplate, NotFoundTemplate, UnsubscribeConfirmTemplate, UnsubscribeTemplate,
+    },
 };
 use anyhow::Context;
 use askama::Template;
 use axum::{
+    Form,
     extract::{Query, State},
     response::{Html, IntoResponse, Response},
 };
 use reqwest::StatusCode;
-use sqlx::Executor;
+use sqlx::{Executor, PgPool};
 
 #[derive(serde::Deserialize)]
 pub struct UnsubQueryParams {
     token: String,
 }
 
-pub async fn unsubscribe(
+pub async fn get_unsubscribe() -> Response {
+    Html(UnsubscribeTemplate.render().unwrap()).into_response()
+}
+
+#[derive(serde::Deserialize)]
+pub struct UnsubFormData {
+    email: String,
+}
+
+pub async fn post_unsubscribe(
+    State(AppState {
+        connection_pool,
+        email_client,
+        base_url,
+    }): State<AppState>,
+    Form(UnsubFormData { email }): Form<UnsubFormData>,
+) -> Result<Response, AppError> {
+    let subscriber_email = SubscriberEmail::parse(email)?;
+    if let Some(token) = fetch_unsubscribe_token(&connection_pool, &subscriber_email)
+        .await
+        .context("Could not fetch unsubscribe token.")?
+    {
+        send_unsubscribe_email(&email_client, &subscriber_email, &base_url, &token)
+            .await
+            .context("Failed to send a confirmation email.")?;
+    }
+    let template = MessageTemplate::Success {
+        message: "If you are a subscriber, you'll receive a confirmation link shortly.".into(),
+    };
+    Ok(Html(template.render().unwrap()).into_response())
+}
+
+#[tracing::instrument(name = "Fetching unsubscribe token from the database", skip_all)]
+async fn fetch_unsubscribe_token(
+    connection_pool: &PgPool,
+    subscriber_email: &SubscriberEmail,
+) -> Result<Option<String>, sqlx::Error> {
+    let r = sqlx::query!(
+        "SELECT unsubscribe_token FROM subscriptions WHERE email = $1",
+        subscriber_email.as_ref()
+    )
+    .fetch_optional(connection_pool)
+    .await?;
+
+    Ok(r.and_then(|r| r.unsubscribe_token))
+}
+
+#[tracing::instrument(name = "Send an unsubscribe confirmation email", skip_all)]
+pub async fn send_unsubscribe_email(
+    email_client: &EmailClient,
+    subscriber_email: &SubscriberEmail,
+    base_url: &str,
+    unsubscribe_token: &str,
+) -> Result<(), reqwest::Error> {
+    let confirmation_link = format!(
+        "{}/unsubscribe/confirm?token={}",
+        base_url, unsubscribe_token
+    );
+    let html_content = format!(
+        "You've requested to unsubscribe from my emails. To confirm, please click the link below:<br />\
+<a href=\"{}\">Confirm unsubscribe</a><br />\
+If you did not request this, you can safely ignore this email.",
+        confirmation_link
+    );
+    let text_content = format!(
+        "You've requested to unsubscribe from my emails. To confirm, please follow the link below:\
+{}\
+If you did not request this, you can safely ignore this email.",
+        confirmation_link
+    );
+    email_client
+        .send_email(
+            subscriber_email,
+            "I will miss you",
+            &html_content,
+            &text_content,
+        )
+        .await
+}
+
+#[tracing::instrument(name = "Removing user from database if he exists", skip_all)]
+pub async fn unsubscribe_confirm(
     Query(UnsubQueryParams { token }): Query<UnsubQueryParams>,
     State(AppState {
         connection_pool, ..
@@ -33,12 +119,14 @@ pub async fn unsubscribe(
         .context("Could not update subscriptions table.")?;
 
     if result.rows_affected() == 0 {
+        tracing::info!("Unsubscribe token is not tied to any confirmed user");
         Ok((
             StatusCode::NOT_FOUND,
             Html(NotFoundTemplate.render().unwrap()),
         )
             .into_response())
     } else {
-        Ok(Html(UnsubscribeTemplate.render().unwrap()).into_response())
+        tracing::info!("User successfully removed");
+        Ok(Html(UnsubscribeConfirmTemplate.render().unwrap()).into_response())
     }
 }