chore: Started authentication process with axum-login

src/models/auth.rs

@@ -0,0 +1,67 @@
+use std::collections::HashMap;
+
+use axum_login::{AuthUser, AuthnBackend, UserId};
+
+// User model - whatever type for `id` is used here needs to be reflected
+// in `AuthUser::Id` type value as well
+#[derive(Debug, Clone)]
+pub struct User {
+    id: i32,
+    pw_hash: Vec<u8>,
+}
+
+impl AuthUser for User {
+    type Id = i32;
+
+    fn id(&self) -> Self::Id {
+        self.id
+    }
+
+    // TODO: In the future, this would also be based off any other security
+    // factors, like email, phone number, 2FA/MFA, etc., so changing any of
+    // those factors would invalidate the session
+    fn session_auth_hash(&self) -> &[u8] {
+        &self.pw_hash
+    }
+}
+
+#[derive(Clone)]
+struct Backend {
+    // Placeholder for a list of sessions that could/would come from database
+    users: HashMap<i32, User>,
+}
+
+// This is what is used to attempt to login. In this case, if someone attempts
+// to login with just a user_id, they will succeed if it is a valid ID. To make
+// this a user/password login, the properties could be `username: String` and
+// `password: String`, then update the authentication function to get a user_id
+// from that to return from the `users.get(&User::Id)`
+#[derive(Clone)]
+struct Credentials {
+    user_id: i32,
+}
+
+impl AuthnBackend for Backend {
+    type User = User;
+    type Credentials = Credentials;
+    type Error = std::convert::Infallible;
+
+    async fn authenticate(
+        &self,
+        Credentials { user_id }: Self::Credentials,
+    ) -> Result<Option<Self::User>, Self::Error> {
+        // ex:
+        // if let Some(user) = self.find_user_by_username(&creds.username) {
+        //     if verify_password(&creds.password, &user.password_hash) {
+        //         return Ok(Some(user));
+        //     }
+        // }
+        // Ok(None)
+
+        Ok(self.users.get(&user_id).cloned())
+    }
+
+    async fn get_user(&self, user_id: &UserId<Self>) -> Result<Option<Self::User>, Self::Error> {
+        Ok(self.users.get(user_id).cloned())
+    }
+}

src/models/mod.rs

@@ -1,2 +1,3 @@
+pub mod auth;
 pub mod config;
 pub mod state;