Return the username in a separate service

This allows us to use a service implementation which
returns a dummy user during development and the actual authenticated
user during production.  It also simplifies tests.

app/src/main.rs

@@ -12,7 +12,15 @@ async fn main() {
     let hello_dao = dao_impl::HelloDaoImpl::new(pool.clone());
     let permission_dao = dao_impl::PermissionDaoImpl::new(pool);
 
-    let permission_service = service_impl::PermissionServiceImpl::new(permission_dao.into());
+    // Always authenticate with DEVUSER during development.
+    // This is used to test the permission service locally without a login service.
+    //
+    // TODO: Implement a proper authentication service when used in produciton. Maybe
+    // use differnet implementations on debug then on release.  Or control it via a
+    // feature.
+    let user_service = service_impl::UserServiceDev;
+    let permission_service =
+        service_impl::PermissionServiceImpl::new(permission_dao.into(), user_service.into());
     let hello_service =
         service_impl::HelloServiceImpl::new(hello_dao.into(), permission_service.into());
     rest::start_server(hello_service).await

service/src/lib.rs

@@ -19,6 +19,8 @@ pub trait PermissionService {
         &self,
         privilege: &str,
     ) -> impl Future<Output = Result<(), ServiceError>> + Send;
+}
 
+pub trait UserService {
     fn current_user(&self) -> impl Future<Output = Result<Arc<str>, ServiceError>> + Send;
 }

service_impl/src/lib.rs

@@ -33,27 +33,35 @@ where
     }
 }
 
-pub struct PermissionServiceImpl<PermissionDao>
+pub struct PermissionServiceImpl<PermissionDao, UserService>
 where
     PermissionDao: dao::PermissionDao + Send + Sync,
+    UserService: service::UserService + Send + Sync,
 {
     permission_dao: Arc<PermissionDao>,
+    user_service: Arc<UserService>,
 }
-impl<PermissionDao> PermissionServiceImpl<PermissionDao>
+impl<PermissionDao, UserService> PermissionServiceImpl<PermissionDao, UserService>
 where
     PermissionDao: dao::PermissionDao + Send + Sync,
+    UserService: service::UserService + Send + Sync,
 {
-    pub fn new(permission_dao: Arc<PermissionDao>) -> Self {
-        Self { permission_dao }
+    pub fn new(permission_dao: Arc<PermissionDao>, user_service: Arc<UserService>) -> Self {
+        Self {
+            permission_dao,
+            user_service,
+        }
     }
 }
 
-impl<PermissionDao> service::PermissionService for PermissionServiceImpl<PermissionDao>
+impl<PermissionDao, UserService> service::PermissionService
+    for PermissionServiceImpl<PermissionDao, UserService>
 where
     PermissionDao: dao::PermissionDao + Send + Sync,
+    UserService: service::UserService + Send + Sync,
 {
     async fn check_permission(&self, privilege: &str) -> Result<(), service::ServiceError> {
-        let current_user = self.current_user().await?;
+        let current_user = self.user_service.current_user().await?;
         if self
             .permission_dao
             .has_privilege(current_user.as_ref(), privilege)
@@ -64,7 +72,11 @@ where
             Err(service::ServiceError::Forbidden)
         }
     }
+}
 
+pub struct UserServiceDev;
+
+impl service::UserService for UserServiceDev {
     async fn current_user(&self) -> Result<Arc<str>, service::ServiceError> {
         Ok("DEVUSER".into())
     }