rust_web_server/async_state/
mod.rs

1//! Async-capable state-aware application — requires the `http2` feature (tokio).
2//!
3//! [`AsyncAppWithState<S>`] is the async counterpart to [`AppWithState<S>`]:
4//! handlers are `async fn` closures that can `await` database queries, HTTP
5//! clients, or any other async I/O without blocking the OS thread.
6//!
7//! The sync [`Application`] bridge works in any calling context: when inside
8//! an existing tokio runtime (HTTP/2 / HTTP/3), it spawns a scoped OS thread
9//! with its own single-threaded runtime; when called from the HTTP/1.1
10//! thread-pool (no runtime), it creates a temporary single-threaded runtime.
11//!
12//! Unmatched routes fall through to the built-in [`App`] controller chain.
13//!
14//! # Example
15//!
16//! ```rust,no_run
17//! use std::sync::Arc;
18//! use rust_web_server::async_state::AsyncAppWithState;
19//! use rust_web_server::core::New;
20//! use rust_web_server::response::{Response, STATUS_CODE_REASON_PHRASE};
21//! use rust_web_server::range::Range;
22//! use rust_web_server::mime_type::MimeType;
23//! use rust_web_server::router::PathParams;
24//! use rust_web_server::request::Request;
25//! use rust_web_server::server::ConnectionInfo;
26//!
27//! struct AppState {
28//!     greeting: String,
29//! }
30//!
31//! let app = AsyncAppWithState::new(AppState { greeting: "Hello".to_string() })
32//!     .get("/greet/:name", |_req, params, _conn, state| async move {
33//!         let name = params.get("name").unwrap_or("world");
34//!         let body = format!("{}, {}!", state.greeting, name);
35//!         let mut r = Response::new();
36//!         r.status_code = *STATUS_CODE_REASON_PHRASE.n200_ok.status_code;
37//!         r.reason_phrase = STATUS_CODE_REASON_PHRASE.n200_ok.reason_phrase.to_string();
38//!         r.content_range_list = vec![
39//!             Range::get_content_range(body.into_bytes(), MimeType::TEXT_PLAIN.to_string())
40//!         ];
41//!         r
42//!     });
43//! ```
44//!
45//! [`AppWithState<S>`]: crate::state::AppWithState
46
47#[cfg(test)]
48mod tests;
49
50use std::collections::HashMap;
51use std::future::Future;
52use std::pin::Pin;
53use std::sync::Arc;
54
55use crate::app::App;
56use crate::application::Application;
57use crate::core::New;
58use crate::request::Request;
59use crate::response::Response;
60use crate::router::PathParams;
61use crate::server::ConnectionInfo;
62
63type BoxFuture<T> = Pin<Box<dyn Future<Output = T> + Send + 'static>>;
64
65type AsyncHandlerFn<S> = Box<
66    dyn Fn(Request, PathParams, ConnectionInfo, Arc<S>) -> BoxFuture<Response> + Send + Sync,
67>;
68
69// ── Internal pattern matching (mirrors Router) ────────────────────────────────
70
71enum Segment {
72    Literal(String),
73    Param(String),
74    Wildcard(String),
75}
76
77fn parse_pattern(pattern: &str) -> Vec<Segment> {
78    if pattern == "/" {
79        return vec![];
80    }
81    pattern
82        .split('/')
83        .filter(|s| !s.is_empty())
84        .map(|seg| {
85            if let Some(name) = seg.strip_prefix(':') {
86                Segment::Param(name.to_string())
87            } else if let Some(name) = seg.strip_prefix('*') {
88                Segment::Wildcard(name.to_string())
89            } else {
90                Segment::Literal(seg.to_string())
91            }
92        })
93        .collect()
94}
95
96fn try_match(pattern: &[Segment], path: &[&str]) -> Option<HashMap<String, String>> {
97    let mut params = HashMap::new();
98    let mut pi = 0;
99
100    for (si, seg) in pattern.iter().enumerate() {
101        match seg {
102            Segment::Literal(lit) => {
103                if pi >= path.len() || path[pi] != lit.as_str() {
104                    return None;
105                }
106                pi += 1;
107            }
108            Segment::Param(name) => {
109                if pi >= path.len() {
110                    return None;
111                }
112                params.insert(name.clone(), path[pi].to_string());
113                pi += 1;
114            }
115            Segment::Wildcard(name) => {
116                if si != pattern.len() - 1 {
117                    return None;
118                }
119                params.insert(name.clone(), path[pi..].join("/"));
120                pi = path.len();
121            }
122        }
123    }
124
125    if pi == path.len() { Some(params) } else { None }
126}
127
128// ── AsyncRoute ────────────────────────────────────────────────────────────────
129
130struct AsyncRoute<S> {
131    method: String,
132    segments: Vec<Segment>,
133    handler: AsyncHandlerFn<S>,
134}
135
136// ── AsyncAppWithState ─────────────────────────────────────────────────────────
137
138/// An [`Application`] whose route handlers are `async` functions.
139///
140/// State is stored as `Arc<S>` and passed by value (cheap clone) to each
141/// handler invocation. Handlers receive owned `Request`, `PathParams`, and
142/// `ConnectionInfo` values so the returned future is `'static`.
143pub struct AsyncAppWithState<S> {
144    state: Arc<S>,
145    routes: Vec<AsyncRoute<S>>,
146}
147
148impl<S: Send + Sync + 'static> AsyncAppWithState<S> {
149    /// Create a new `AsyncAppWithState` wrapping `state`.
150    pub fn new(state: S) -> Self {
151        AsyncAppWithState { state: Arc::new(state), routes: Vec::new() }
152    }
153
154    /// Return a reference to the shared state.
155    pub fn state(&self) -> &S {
156        &self.state
157    }
158
159    fn add<F, Fut>(mut self, method: &str, pattern: &str, handler: F) -> Self
160    where
161        F: Fn(Request, PathParams, ConnectionInfo, Arc<S>) -> Fut + Send + Sync + 'static,
162        Fut: Future<Output = Response> + Send + 'static,
163    {
164        self.routes.push(AsyncRoute {
165            method: method.to_string(),
166            segments: parse_pattern(pattern),
167            handler: Box::new(move |req, params, conn, state| Box::pin(handler(req, params, conn, state))),
168        });
169        self
170    }
171
172    /// Register an async `GET` handler for `pattern`.
173    pub fn get<F, Fut>(self, pattern: &str, handler: F) -> Self
174    where
175        F: Fn(Request, PathParams, ConnectionInfo, Arc<S>) -> Fut + Send + Sync + 'static,
176        Fut: Future<Output = Response> + Send + 'static,
177    {
178        self.add("GET", pattern, handler)
179    }
180
181    /// Register an async `POST` handler for `pattern`.
182    pub fn post<F, Fut>(self, pattern: &str, handler: F) -> Self
183    where
184        F: Fn(Request, PathParams, ConnectionInfo, Arc<S>) -> Fut + Send + Sync + 'static,
185        Fut: Future<Output = Response> + Send + 'static,
186    {
187        self.add("POST", pattern, handler)
188    }
189
190    /// Register an async `PUT` handler for `pattern`.
191    pub fn put<F, Fut>(self, pattern: &str, handler: F) -> Self
192    where
193        F: Fn(Request, PathParams, ConnectionInfo, Arc<S>) -> Fut + Send + Sync + 'static,
194        Fut: Future<Output = Response> + Send + 'static,
195    {
196        self.add("PUT", pattern, handler)
197    }
198
199    /// Register an async `PATCH` handler for `pattern`.
200    pub fn patch<F, Fut>(self, pattern: &str, handler: F) -> Self
201    where
202        F: Fn(Request, PathParams, ConnectionInfo, Arc<S>) -> Fut + Send + Sync + 'static,
203        Fut: Future<Output = Response> + Send + 'static,
204    {
205        self.add("PATCH", pattern, handler)
206    }
207
208    /// Register an async `DELETE` handler for `pattern`.
209    pub fn delete<F, Fut>(self, pattern: &str, handler: F) -> Self
210    where
211        F: Fn(Request, PathParams, ConnectionInfo, Arc<S>) -> Fut + Send + Sync + 'static,
212        Fut: Future<Output = Response> + Send + 'static,
213    {
214        self.add("DELETE", pattern, handler)
215    }
216
217    async fn execute_async(
218        &self,
219        request: &Request,
220        connection: &ConnectionInfo,
221    ) -> Result<Response, String> {
222        let path = request.request_uri.split('?').next().unwrap_or(&request.request_uri);
223        let path_segs: Vec<&str> = path.split('/').filter(|s| !s.is_empty()).collect();
224
225        for route in &self.routes {
226            if route.method != request.method {
227                continue;
228            }
229            if let Some(params_map) = try_match(&route.segments, &path_segs) {
230                let params = PathParams::from_map(params_map);
231                let fut = (route.handler)(
232                    request.clone(),
233                    params,
234                    connection.clone(),
235                    Arc::clone(&self.state),
236                );
237                return Ok(fut.await);
238            }
239        }
240
241        App::new().execute(request, connection)
242    }
243}
244
245impl<S: Send + Sync + 'static> Application for AsyncAppWithState<S> {
246    fn execute(&self, request: &Request, connection: &ConnectionInfo) -> Result<Response, String> {
247        let request = request.clone();
248        let connection = connection.clone();
249        match tokio::runtime::Handle::try_current() {
250            Ok(_) => {
251                // Inside an existing runtime: run the future on a scoped OS thread
252                // with its own single-threaded runtime to avoid blocking the event loop.
253                std::thread::scope(|s| {
254                    s.spawn(|| {
255                        tokio::runtime::Builder::new_current_thread()
256                            .enable_all()
257                            .build()
258                            .unwrap()
259                            .block_on(self.execute_async(&request, &connection))
260                    })
261                    .join()
262                    .unwrap()
263                })
264            }
265            Err(_) => {
266                // Not inside any runtime (HTTP/1.1 thread pool): create a temporary one.
267                tokio::runtime::Builder::new_current_thread()
268                    .enable_all()
269                    .build()
270                    .unwrap()
271                    .block_on(self.execute_async(&request, &connection))
272            }
273        }
274    }
275}
rust_web_server/async_state/mod.rs

rust_web_server/async_state/
mod.rs
