wasmtime_wasi_http/p3/
response.rs

1use crate::p3::bindings::http::types::ErrorCode;
2use crate::p3::body::{Body, GuestBody};
3use crate::p3::{WasiHttpCtxView, WasiHttpView};
4use crate::{FieldMap, get_content_length};
5use bytes::Bytes;
6use http::StatusCode;
7use http_body_util::BodyExt as _;
8use http_body_util::combinators::UnsyncBoxBody;
9use wasmtime::AsContextMut;
10use wasmtime::error::Context as _;
11
12/// The concrete type behind a `wasi:http/types.response` resource.
13pub struct Response {
14    /// The status of the response.
15    pub status: StatusCode,
16    /// The headers of the response.
17    pub headers: FieldMap,
18    /// Response body.
19    pub(crate) body: Body,
20}
21
22impl TryFrom<Response> for http::Response<Body> {
23    type Error = http::Error;
24
25    fn try_from(
26        Response {
27            status,
28            headers,
29            body,
30        }: Response,
31    ) -> Result<Self, Self::Error> {
32        let mut res = http::Response::builder().status(status);
33        *res.headers_mut().unwrap() = headers.into();
34        res.body(body)
35    }
36}
37
38impl Response {
39    /// Convert [Response] into [http::Response].
40    ///
41    /// The specified [Future] `fut` can be used to communicate
42    /// a response processing error, if any, to the constructor of the response.
43    /// For example, if the response was constructed via `wasi:http/types.response#new`,
44    /// a result sent on `fut` will be forwarded to the guest on the future handle returned.
45    pub fn into_http<T: WasiHttpView + 'static>(
46        self,
47        store: impl AsContextMut<Data = T>,
48        fut: impl Future<Output = Result<(), ErrorCode>> + Send + 'static,
49    ) -> wasmtime::Result<http::Response<UnsyncBoxBody<Bytes, ErrorCode>>> {
50        self.into_http_with_getter(store, fut, T::http)
51    }
52
53    /// Like [`Self::into_http`], but with a custom function for converting `T`
54    /// to a [`WasiHttpCtxView`].
55    pub fn into_http_with_getter<T: 'static>(
56        self,
57        store: impl AsContextMut<Data = T>,
58        fut: impl Future<Output = Result<(), ErrorCode>> + Send + 'static,
59        getter: fn(&mut T) -> WasiHttpCtxView<'_>,
60    ) -> wasmtime::Result<http::Response<UnsyncBoxBody<Bytes, ErrorCode>>> {
61        let res = http::Response::try_from(self)?;
62        let (res, body) = res.into_parts();
63        let body = match body {
64            Body::Guest {
65                contents_rx,
66                trailers_rx,
67                result_tx,
68            } => {
69                // `Content-Length` header value is validated in `fields` implementation
70                let content_length =
71                    get_content_length(&res.headers).context("failed to parse `content-length`")?;
72                GuestBody::new(
73                    store,
74                    contents_rx,
75                    trailers_rx,
76                    result_tx,
77                    fut,
78                    content_length,
79                    ErrorCode::HttpResponseBodySize,
80                    getter,
81                )?
82                .boxed_unsync()
83            }
84            Body::Host { body, result_tx } => {
85                _ = result_tx.send(Box::new(fut));
86                body
87            }
88        };
89        Ok(http::Response::from_parts(res, body))
90    }
91
92    /// Convert [http::Response] into [Response].
93    pub fn from_http<T>(
94        res: http::Response<T>,
95    ) -> (
96        Self,
97        impl Future<Output = Result<(), ErrorCode>> + Send + 'static,
98    )
99    where
100        T: http_body::Body<Data = Bytes> + Send + 'static,
101        T::Error: Into<ErrorCode>,
102    {
103        let (parts, body) = res.into_parts();
104        let (result_tx, result_rx) = tokio::sync::oneshot::channel();
105
106        let wasi_response = Response {
107            status: parts.status,
108            headers: FieldMap::new_immutable(parts.headers),
109            body: Body::Host {
110                body: body.map_err(Into::into).boxed_unsync(),
111                result_tx,
112            },
113        };
114
115        let io_future = async {
116            let Ok(fut) = result_rx.await else {
117                return Ok(());
118            };
119            Box::into_pin(fut).await
120        };
121
122        (wasi_response, io_future)
123    }
124}
125
126#[cfg(test)]
127mod tests {
128    use super::*;
129    use core::future::Future;
130    use core::pin::pin;
131    use core::task::{Context, Poll, Waker};
132    use http_body_util::Full;
133
134    #[tokio::test]
135    async fn test_response_from_http() {
136        let http_response = http::Response::builder()
137            .status(StatusCode::OK)
138            .header("x-custom-header", "value123")
139            .body(Full::new(Bytes::from_static(b"hello wasm")))
140            .unwrap();
141
142        let (wasi_resp, io_future) = Response::from_http(http_response);
143        assert_eq!(wasi_resp.status, StatusCode::OK);
144        assert_eq!(
145            wasi_resp.headers.get("x-custom-header").unwrap(),
146            "value123"
147        );
148        match wasi_resp.body {
149            Body::Host { body, result_tx } => {
150                let collected = body.collect().await;
151                assert!(collected.is_ok(), "Body stream failed unexpectedly");
152                let chunks = collected.unwrap().to_bytes();
153                assert_eq!(chunks, &b"hello wasm"[..]);
154                _ = result_tx.send(Box::new(async { Ok(()) }));
155            }
156            _ => panic!("Response body should be of type Host"),
157        }
158
159        let mut cx = Context::from_waker(Waker::noop());
160        let result = pin!(io_future).poll(&mut cx);
161        assert!(matches!(result, Poll::Ready(Ok(_))));
162    }
163}
wasmtime_wasi_http/p3/response.rs

wasmtime_wasi_http/p3/
response.rs
