refactor(http): extract Axum extractor for the URL path param key

src/http/axum_implementation/extractors/key.rs

@@ -0,0 +1,55 @@
+use std::panic::Location;
+
+use axum::async_trait;
+use axum::extract::{FromRequestParts, Path};
+use axum::http::request::Parts;
+use axum::response::{IntoResponse, Response};
+
+use crate::http::axum_implementation::handlers::auth::{self, KeyIdParam};
+use crate::http::axum_implementation::responses;
+use crate::tracker::auth::KeyId;
+
+pub struct ExtractKeyId(pub KeyId);
+
+#[async_trait]
+impl<S> FromRequestParts<S> for ExtractKeyId
+where
+    S: Send + Sync,
+{
+    type Rejection = Response;
+
+    async fn from_request_parts(parts: &mut Parts, state: &S) -> Result<Self, Self::Rejection> {
+        match Path::<KeyIdParam>::from_request_parts(parts, state).await {
+            Ok(key_id_param) => {
+                let Ok(key_id) = key_id_param.0.value().parse::<KeyId>() else {
+                    return Err(responses::error::Error::from(
+                        auth::Error::InvalidKeyFormat {
+                            location: Location::caller()
+                        })
+                    .into_response())
+                };
+                Ok(ExtractKeyId(key_id))
+            }
+            Err(rejection) => match rejection {
+                axum::extract::rejection::PathRejection::FailedToDeserializePathParams(_) => {
+                    return Err(responses::error::Error::from(auth::Error::InvalidKeyFormat {
+                        location: Location::caller(),
+                    })
+                    .into_response())
+                }
+                axum::extract::rejection::PathRejection::MissingPathParams(_) => {
+                    return Err(responses::error::Error::from(auth::Error::MissingAuthKey {
+                        location: Location::caller(),
+                    })
+                    .into_response())
+                }
+                _ => {
+                    return Err(responses::error::Error::from(auth::Error::CannotExtractKeyParam {
+                        location: Location::caller(),
+                    })
+                    .into_response())
+                }
+            },
+        }
+    }
+}

src/http/axum_implementation/extractors/mod.rs

@@ -1,4 +1,5 @@
 pub mod announce_request;
+pub mod key;
 pub mod peer_ip;
 pub mod remote_client_ip;
 pub mod scrape_request;

src/http/axum_implementation/handlers/announce.rs

@@ -3,20 +3,19 @@ use std::panic::Location;
 use std::sync::Arc;
 
 use aquatic_udp_protocol::{AnnounceEvent, NumberOfBytes};
-use axum::extract::{Path, State};
+use axum::extract::State;
 use axum::response::{IntoResponse, Response};
 use log::debug;
 
-use super::auth::KeyIdParam;
 use crate::http::axum_implementation::extractors::announce_request::ExtractRequest;
+use crate::http::axum_implementation::extractors::key::ExtractKeyId;
 use crate::http::axum_implementation::extractors::peer_ip;
 use crate::http::axum_implementation::extractors::remote_client_ip::RemoteClientIp;
 use crate::http::axum_implementation::handlers::auth;
 use crate::http::axum_implementation::requests::announce::{Announce, Compact, Event};
 use crate::http::axum_implementation::responses::{self, announce};
 use crate::http::axum_implementation::services;
 use crate::protocol::clock::{Current, Time};
-use crate::tracker::auth::KeyId;
 use crate::tracker::peer::Peer;
 use crate::tracker::Tracker;
 
@@ -42,20 +41,11 @@ pub async fn handle_without_key(
 pub async fn handle_with_key(
     State(tracker): State<Arc<Tracker>>,
     ExtractRequest(announce_request): ExtractRequest,
-    Path(key_id_param): Path<KeyIdParam>,
+    ExtractKeyId(key_id): ExtractKeyId,
     remote_client_ip: RemoteClientIp,
 ) -> Response {
     debug!("http announce request: {:#?}", announce_request);
 
-    // todo: extract to Axum extractor. Duplicate code in `scrape` handler.
-    let Ok(key_id) = key_id_param.value().parse::<KeyId>() else {
-        return responses::error::Error::from(
-            auth::Error::InvalidKeyFormat {
-                location: Location::caller()
-            })
-        .into_response()
-    };
-
     match tracker.authenticate(&key_id).await {
         Ok(_) => (),
         Err(error) => return responses::error::Error::from(error).into_response(),

src/http/axum_implementation/handlers/auth.rs

@@ -18,10 +18,12 @@ impl KeyIdParam {
 
 #[derive(Debug, Error)]
 pub enum Error {
-    #[error("Missing authentication key for private tracker. Error in {location}")]
+    #[error("Missing authentication key param for private tracker. Error in {location}")]
     MissingAuthKey { location: &'static Location<'static> },
-    #[error("Invalid format authentication key. Error in {location}")]
+    #[error("Invalid format for authentication key param. Error in {location}")]
     InvalidKeyFormat { location: &'static Location<'static> },
+    #[error("Cannot extract authentication key param from URL path. Error in {location}")]
+    CannotExtractKeyParam { location: &'static Location<'static> },
 }
 
 impl From<Error> for responses::error::Error {

src/http/axum_implementation/handlers/scrape.rs

@@ -1,18 +1,15 @@
-use std::panic::Location;
 use std::sync::Arc;
 
-use axum::extract::{Path, State};
+use axum::extract::State;
 use axum::response::{IntoResponse, Response};
 use log::debug;
 
-use super::auth::KeyIdParam;
+use crate::http::axum_implementation::extractors::key::ExtractKeyId;
 use crate::http::axum_implementation::extractors::peer_ip;
 use crate::http::axum_implementation::extractors::remote_client_ip::RemoteClientIp;
 use crate::http::axum_implementation::extractors::scrape_request::ExtractRequest;
-use crate::http::axum_implementation::handlers::auth;
 use crate::http::axum_implementation::requests::scrape::Scrape;
 use crate::http::axum_implementation::{responses, services};
-use crate::tracker::auth::KeyId;
 use crate::tracker::Tracker;
 
 #[allow(clippy::unused_async)]
@@ -34,20 +31,11 @@ pub async fn handle_without_key(
 pub async fn handle_with_key(
     State(tracker): State<Arc<Tracker>>,
     ExtractRequest(scrape_request): ExtractRequest,
-    Path(key_id_param): Path<KeyIdParam>,
+    ExtractKeyId(key_id): ExtractKeyId,
     remote_client_ip: RemoteClientIp,
 ) -> Response {
     debug!("http scrape request: {:#?}", &scrape_request);
 
-    // todo: extract to Axum extractor. Duplicate code in `announce` handler.
-    let Ok(key_id) = key_id_param.value().parse::<KeyId>() else {
-        return responses::error::Error::from(
-            auth::Error::InvalidKeyFormat {
-                location: Location::caller()
-            })
-        .into_response()
-    };
-
     match tracker.authenticate(&key_id).await {
         Ok(_) => (),
         Err(_) => return handle_fake_scrape(&tracker, &scrape_request, &remote_client_ip).await,