Error handling refactor and 500 page/message templates

src/routes/subscriptions.rs

@@ -1,15 +1,15 @@
 use crate::{
     domain::{NewSubscriber, SubscriberEmail},
     email_client::EmailClient,
+    routes::AppError,
     startup::AppState,
     templates::MessageTemplate,
 };
 use anyhow::Context;
 use askama::Template;
 use axum::{
-    Form, Json,
+    Form,
     extract::State,
-    http::StatusCode,
     response::{Html, IntoResponse, Response},
 };
 use chrono::Utc;
@@ -42,45 +42,6 @@ pub fn error_chain_fmt(
     Ok(())
 }
 
-#[derive(thiserror::Error)]
-pub enum SubscribeError {
-    #[error(transparent)]
-    UnexpectedError(#[from] anyhow::Error),
-    #[error("{0}")]
-    ValidationError(String),
-}
-
-impl std::fmt::Debug for SubscribeError {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        error_chain_fmt(self, f)
-    }
-}
-
-impl IntoResponse for SubscribeError {
-    fn into_response(self) -> Response {
-        #[derive(serde::Serialize)]
-        struct ErrorResponse<'a> {
-            message: &'a str,
-        }
-
-        tracing::error!("{:?}", self);
-
-        match self {
-            SubscribeError::UnexpectedError(_) => (
-                StatusCode::INTERNAL_SERVER_ERROR,
-                Json(ErrorResponse {
-                    message: "An internal server error occured.",
-                }),
-            )
-                .into_response(),
-            SubscribeError::ValidationError(e) => {
-                let template = MessageTemplate::Error { message: e };
-                Html(template.render().unwrap()).into_response()
-            }
-        }
-    }
-}
-
 #[tracing::instrument(
     name = "Adding a new subscriber",
     skip(connection_pool, email_client, base_url, form),
@@ -96,13 +57,11 @@ pub async fn subscribe(
         ..
     }): State<AppState>,
     Form(form): Form<SubscriptionFormData>,
-) -> Result<Response, SubscribeError> {
-    let new_subscriber = match form.try_into() {
-        Ok(new_sub) => new_sub,
-        Err(e) => {
-            return Err(SubscribeError::ValidationError(e));
-        }
-    };
+) -> Result<Response, AppError> {
+    let new_subscriber = form
+        .try_into()
+        .context("Failed to parse subscription form data.")
+        .map_err(AppError::FormError)?;
     let mut transaction = connection_pool
         .begin()
         .await
@@ -122,6 +81,7 @@ pub async fn subscribe(
     )
     .await
     .context("Failed to send a confirmation email.")?;
+
     transaction
         .commit()
         .await
@@ -214,7 +174,7 @@ pub struct SubscriptionFormData {
 }
 
 impl TryFrom<SubscriptionFormData> for NewSubscriber {
-    type Error = String;
+    type Error = anyhow::Error;
 
     fn try_from(value: SubscriptionFormData) -> Result<Self, Self::Error> {
         let email = SubscriberEmail::parse(value.email)?;