scaffolded auth backend type

engine/Cargo.toml

@@ -7,6 +7,7 @@ members = ["crates/*"]
 tokio = { version = "1.35.1", features = ["full"] }
 color-eyre = "0.6.2"
 axum = "0.7.4"
+thiserror = "1.0.56"
 tracing = "0.1.40"
 tracing-subscriber = "0.3.18"
 serde = { version = "1.0.196", features = ["derive"] }

engine/crates/auth/Cargo.toml

@@ -8,4 +8,9 @@ edition = "2021"
 [dependencies]
 axum-login = "0.13.1"
 serde.workspace = true
+color-eyre.workspace = true
+thiserror.workspace = true
 surrealdb.workspace = true
+
+clients = { path = "../clients" }
+async-trait = "0.1.77"

engine/crates/auth/src/lib.rs

@@ -1,4 +1,4 @@
-use axum_login::AuthUser;
+use axum_login::{AuthUser, AuthnBackend, UserId};
 use serde::{Deserialize, Serialize};
 use surrealdb::sql::Thing;
 
@@ -25,3 +25,46 @@ impl AuthUser for AuthenticatedUser {
   fn id(&self) -> Self::Id { self.id.clone() }
   fn session_auth_hash(&self) -> &[u8] { self.password.as_bytes() }
 }
+
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub struct Credentials {
+  pub username: String,
+  pub password: String,
+  pub next:     Option<String>,
+}
+
+#[derive(Clone)]
+pub struct Backend {
+  surreal_client: clients::surreal::SurrealRootClient,
+}
+
+impl Backend {
+  pub async fn new() -> color_eyre::Result<Self> {
+    Ok(Self {
+      surreal_client: clients::surreal::SurrealRootClient::new().await?,
+    })
+  }
+}
+
+#[async_trait::async_trait]
+impl AuthnBackend for Backend {
+  type User = AuthenticatedUser;
+  type Credentials = Credentials;
+  type Error = std::convert::Infallible;
+
+  async fn authenticate(
+    &self,
+    credentials: Self::Credentials,
+  ) -> Result<Option<Self::User>, Self::Error> {
+    let surreal_client = &self.surreal_client;
+
+    Ok(None)
+  }
+
+  async fn get_user(
+    &self,
+    user_id: &UserId<Self>,
+  ) -> Result<Option<Self::User>, Self::Error> {
+    Ok(None)
+  }
+}

engine/crates/clients/src/surreal.rs

@@ -10,6 +10,7 @@ use surrealdb::{
 };
 
 /// A root-level client for the SurrealDB database.
+#[derive(Clone, Debug)]
 pub struct SurrealRootClient {
   client: surrealdb::Surreal<Client>,
 }