From f43e143bf6002b97ab75301b70201008f40774de Mon Sep 17 00:00:00 2001
From: Alphonse Paix <alphonse.paix@outlook.com>
Date: Sat, 27 Sep 2025 02:28:04 +0200
Subject: [PATCH] custom extractors rejection

---
 src/routes.rs                       | 55 +++++++++++++++++++++++++++--
 src/routes/admin/posts.rs           |  6 ++--
 src/routes/admin/subscribers.rs     |  4 +--
 src/routes/posts.rs                 |  6 ++--
 src/routes/subscriptions_confirm.rs |  8 +++--
 templates/unsubscribe.html          |  2 +-
 6 files changed, 68 insertions(+), 13 deletions(-)

diff --git a/src/routes.rs b/src/routes.rs
index b269bd3..474c00f 100644
--- a/src/routes.rs
+++ b/src/routes.rs
@@ -10,7 +10,8 @@ mod unsubscribe;
 pub use admin::*;
 use askama::Template;
 use axum::{
-    http::HeaderMap,
+    extract::FromRequestParts,
+    http::{HeaderMap, request::Parts},
     response::{Html, IntoResponse, Response},
 };
 pub use health_check::*;
@@ -19,6 +20,7 @@ pub use login::*;
 pub use posts::*;
 use rand::{Rng, distr::Alphanumeric};
 use reqwest::StatusCode;
+use serde::de::DeserializeOwned;
 pub use subscriptions::*;
 pub use subscriptions_confirm::*;
 pub use unsubscribe::*;
@@ -61,6 +63,8 @@ pub enum AppError {
     FormError(#[source] anyhow::Error),
     #[error("Authentication is required.")]
     NotAuthenticated,
+    #[error("Handler extractor failed.")]
+    Extractor(#[source] anyhow::Error),
 }
 
 impl From<anyhow::Error> for AppError {
@@ -124,6 +128,7 @@ impl IntoResponse for AppError {
                 headers.insert("HX-Redirect", "/login".parse().unwrap());
                 (StatusCode::OK, headers).into_response()
             }
+            AppError::Extractor(_) => not_found_html(),
         }
     }
 }
@@ -155,6 +160,50 @@ impl From<AuthError> for AppError {
 }
 
 pub async fn not_found() -> Response {
-    let template = HtmlTemplate(NotFoundTemplate);
-    (StatusCode::NOT_FOUND, template).into_response()
+    (StatusCode::NOT_FOUND, not_found_html()).into_response()
+}
+
+pub fn not_found_html() -> Response {
+    let template = HtmlTemplate(NotFoundTemplate);
+    template.into_response()
+}
+
+pub struct Path<T>(T);
+
+impl<T, S> FromRequestParts<S> for Path<T>
+where
+    T: DeserializeOwned + Send,
+    S: Send + Sync,
+{
+    type Rejection = AppError;
+
+    async fn from_request_parts(parts: &mut Parts, state: &S) -> Result<Self, Self::Rejection> {
+        match axum::extract::Path::<T>::from_request_parts(parts, state).await {
+            Ok(value) => Ok(Self(value.0)),
+            Err(rejection) => Err(AppError::Extractor(anyhow::anyhow!(
+                "Path rejection: {:?}",
+                rejection
+            ))),
+        }
+    }
+}
+
+pub struct Query<T>(pub T);
+
+impl<T, S> FromRequestParts<S> for Query<T>
+where
+    T: DeserializeOwned,
+    S: Send + Sync,
+{
+    type Rejection = AppError;
+
+    async fn from_request_parts(parts: &mut Parts, state: &S) -> Result<Self, Self::Rejection> {
+        match axum::extract::Query::<T>::from_request_parts(parts, state).await {
+            Ok(value) => Ok(Self(value.0)),
+            Err(rejection) => Err(AppError::Extractor(anyhow::anyhow!(
+                "Query rejection: {:?}",
+                rejection
+            ))),
+        }
+    }
 }
diff --git a/src/routes/admin/posts.rs b/src/routes/admin/posts.rs
index a7f676d..b18aca5 100644
--- a/src/routes/admin/posts.rs
+++ b/src/routes/admin/posts.rs
@@ -1,7 +1,9 @@
 use crate::{
     authentication::AuthenticatedUser,
     idempotency::{IdempotencyKey, save_response, try_processing},
-    routes::{AdminError, AppError, EmailType, enqueue_delivery_tasks, insert_newsletter_issue},
+    routes::{
+        AdminError, AppError, EmailType, Path, enqueue_delivery_tasks, insert_newsletter_issue,
+    },
     startup::AppState,
     templates::{MessageTemplate, NewPostEmailTemplate},
 };
@@ -9,7 +11,7 @@ use anyhow::Context;
 use askama::Template;
 use axum::{
     Extension, Form,
-    extract::{Path, State},
+    extract::State,
     response::{Html, IntoResponse, Response},
 };
 use chrono::Utc;
diff --git a/src/routes/admin/subscribers.rs b/src/routes/admin/subscribers.rs
index 663ddf8..9c26d1f 100644
--- a/src/routes/admin/subscribers.rs
+++ b/src/routes/admin/subscribers.rs
@@ -1,13 +1,13 @@
 use crate::{
     domain::SubscriberEntry,
-    routes::AppError,
+    routes::{AppError, Path, Query},
     startup::AppState,
     templates::{MessageTemplate, SubListTemplate},
 };
 use anyhow::Context;
 use askama::Template;
 use axum::{
-    extract::{Path, Query, State},
+    extract::State,
     response::{Html, IntoResponse, Response},
 };
 use sqlx::PgPool;
diff --git a/src/routes/posts.rs b/src/routes/posts.rs
index 422fc92..f001ec8 100644
--- a/src/routes/posts.rs
+++ b/src/routes/posts.rs
@@ -1,13 +1,13 @@
 use crate::{
     domain::PostEntry,
-    routes::{AppError, not_found},
+    routes::{AppError, Path, Query, not_found_html},
     startup::AppState,
     templates::{HtmlTemplate, PostListTemplate, PostTemplate, PostsTemplate},
 };
 use anyhow::Context;
 use askama::Template;
 use axum::{
-    extract::{Path, Query, State},
+    extract::State,
     response::{Html, IntoResponse, Redirect, Response},
 };
 use sqlx::PgPool;
@@ -90,7 +90,7 @@ pub async fn see_post(
         let template = HtmlTemplate(PostTemplate { post });
         Ok(template.into_response())
     } else {
-        Ok(not_found().await)
+        Ok(not_found_html())
     }
 }
 
diff --git a/src/routes/subscriptions_confirm.rs b/src/routes/subscriptions_confirm.rs
index ec6942b..c45a208 100644
--- a/src/routes/subscriptions_confirm.rs
+++ b/src/routes/subscriptions_confirm.rs
@@ -1,7 +1,11 @@
-use crate::{routes::generate_token, startup::AppState, templates::ConfirmTemplate};
+use crate::{
+    routes::{Query, generate_token},
+    startup::AppState,
+    templates::ConfirmTemplate,
+};
 use askama::Template;
 use axum::{
-    extract::{Query, State},
+    extract::State,
     http::StatusCode,
     response::{Html, IntoResponse, Response},
 };
diff --git a/templates/unsubscribe.html b/templates/unsubscribe.html
index 4bdcf21..0c6f3a6 100644
--- a/templates/unsubscribe.html
+++ b/templates/unsubscribe.html
@@ -39,7 +39,7 @@
                                 <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M13 16h-1v-4h-1m1-4h.01M21 12a9 9 0 11-18 0 9 9 0 0118 0z" />
                             </svg>
                             <div class="text-sm text-amber-800">
-                                <p>You will receive an email with an confirmation link.</p>
+                                <p>You will receive an email with a confirmation link.</p>
                             </div>
                         </div>
                     </div>