Responses & errors

Building responses

Handlers return types that implement IntoResponse:

#![allow(unused)]
fn main() {
// 200 text/plain-ish defaults for strings
r.get("/ping", |_c: Call| async { "pong" });

// Explicit status + body
r.post("/items", |_c: Call| async {
    (StatusCode::CREATED, "created")
});

// JSON (feature `json`)
r.get("/note", |_c: Call| async {
    Json(serde_json::json!({ "ok": true }))
});
}

Streaming

Body is always available (no feature flag). Stream large or dynamic payloads without buffering everything in memory:

#![allow(unused)]
fn main() {
use churust::Body;

r.get("/numbers", |_c: Call| async {
    let chunks = futures_util::stream::iter(
        (1..=5).map(|i| Ok::<_, std::io::Error>(bytes::Bytes::from(format!("{i}\n")))),
    );
    Response::stream("text/plain", Body::from_stream(chunks))
});
}

Custom error pages

Use on_error on the app builder to render any 4xx / 5xx, including routing failures, with your own HTML or JSON.

With ContentNegotiation installed (feature json), errors can be rendered as JSON for API clients.

Implement IntoError on your domain error type so handlers can use ?. Churust maps the error to an HTTP status and a safe client-facing body without exposing internal details from Display by default.

Transport-level errors

Security headers and limits apply even when a handler never runs — for example 413 (body too large), 400, and 408 produced by the transport. See Security defaults.

Correct HTTP semantics

Conditional GET for static files (ETag / Last-Modified / 304)
Byte ranges (206 / 416) for static files
Ambiguous framing (both Transfer-Encoding and Content-Length) is refused so leftover bytes cannot become the next request behind a proxy
Repeated query keys on a scalar field are an error, not silent first/last wins

→ Pipeline & plugins

Churust Documentation