use std::collections::{BTreeMap, HashMap}; use std::sync::{Arc, Mutex}; use axum::{ Json, Router, extract::{FromRequestParts, Path, State}, http::{StatusCode, header, request::Parts}, response::{IntoResponse, Response}, routing::{delete, get}, }; use serde_json::json; // A TOY for learning: fixed tokens, no expiry, no HTTPS. Not for real use. #[derive(Clone, Copy, PartialEq, Debug)] enum Role { Member, Librarian, } #[derive(Clone)] struct Caller { name: String, role: Role, } struct AppState { tokens: HashMap, tools: Mutex>, } fn json_error(status: StatusCode, message: &str) -> Response { (status, Json(json!({ "error": message }))).into_response() } impl FromRequestParts> for Caller { type Rejection = Response; async fn from_request_parts(parts: &mut Parts, state: &Arc) -> Result { let token = parts .headers .get(header::AUTHORIZATION) .and_then(|value| value.to_str().ok()) .and_then(|value| value.strip_prefix("Bearer ")); let caller = token.and_then(|t| state.tokens.get(t)); match caller { Some(caller) => Ok(caller.clone()), None => { let mut res = json_error(StatusCode::UNAUTHORIZED, "sign in first"); res.headers_mut().insert(header::WWW_AUTHENTICATE, "Bearer".parse().unwrap()); Err(res) } } } } async fn me(caller: Caller) -> String { format!("signed in as {} ({:?})", caller.name, caller.role) } async fn remove_tool(caller: Caller, State(state): State>, Path(id): Path) -> Response { if caller.role != Role::Librarian { return json_error(StatusCode::FORBIDDEN, "only librarians can remove tools"); } match state.tools.lock().unwrap().remove(&id) { Some(_) => StatusCode::NO_CONTENT.into_response(), None => json_error(StatusCode::NOT_FOUND, "no such tool"), } } fn app() -> Router { let tokens = HashMap::from([ ("tok-ana-7Qx2".to_string(), Caller { name: "ana".to_string(), role: Role::Member }), ("tok-lee-9Fp4".to_string(), Caller { name: "lee".to_string(), role: Role::Librarian }), ]); let tools = BTreeMap::from([(1, "cordless drill".to_string()), (2, "step ladder".to_string())]); let state = Arc::new(AppState { tokens, tools: Mutex::new(tools) }); Router::new() .route("/me", get(me)) .route("/tools/{id}", delete(remove_tool)) .with_state(state) }

authentication