tower_http/services/
redirect.rs

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
//! Service that redirects all requests.
//!
//! # Example
//!
//! Imagine that we run `example.com` and want to redirect all requests using `HTTP` to `HTTPS`.
//! That can be done like so:
//!
//! ```rust
//! use http::{Request, Uri, StatusCode};
//! use http_body_util::Full;
//! use bytes::Bytes;
//! use tower::{Service, ServiceExt};
//! use tower_http::services::Redirect;
//!
//! # #[tokio::main]
//! # async fn main() -> Result<(), Box<dyn std::error::Error>> {
//! let uri: Uri = "https://example.com/".parse().unwrap();
//! let mut service: Redirect<Full<Bytes>> = Redirect::permanent(uri);
//!
//! let request = Request::builder()
//!     .uri("http://example.com")
//!     .body(Full::<Bytes>::default())
//!     .unwrap();
//!
//! let response = service.oneshot(request).await?;
//!
//! assert_eq!(response.status(), StatusCode::PERMANENT_REDIRECT);
//! assert_eq!(response.headers()["location"], "https://example.com/");
//! #
//! # Ok(())
//! # }
//! ```

use http::{header, HeaderValue, Response, StatusCode, Uri};
use std::{
    convert::{Infallible, TryFrom},
    fmt,
    future::Future,
    marker::PhantomData,
    pin::Pin,
    task::{Context, Poll},
};
use tower_service::Service;

/// Service that redirects all requests.
///
/// See the [module docs](crate::services::redirect) for more details.
pub struct Redirect<ResBody> {
    status_code: StatusCode,
    location: HeaderValue,
    // Covariant over ResBody, no dropping of ResBody
    _marker: PhantomData<fn() -> ResBody>,
}

impl<ResBody> Redirect<ResBody> {
    /// Create a new [`Redirect`] that uses a [`307 Temporary Redirect`][mdn] status code.
    ///
    /// [mdn]: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/307
    pub fn temporary(uri: Uri) -> Self {
        Self::with_status_code(StatusCode::TEMPORARY_REDIRECT, uri)
    }

    /// Create a new [`Redirect`] that uses a [`308 Permanent Redirect`][mdn] status code.
    ///
    /// [mdn]: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/308
    pub fn permanent(uri: Uri) -> Self {
        Self::with_status_code(StatusCode::PERMANENT_REDIRECT, uri)
    }

    /// Create a new [`Redirect`] that uses the given status code.
    ///
    /// # Panics
    ///
    /// - If `status_code` isn't a [redirection status code][mdn] (3xx).
    /// - If `uri` isn't a valid [`HeaderValue`].
    ///
    /// [mdn]: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status#redirection_messages
    pub fn with_status_code(status_code: StatusCode, uri: Uri) -> Self {
        assert!(
            status_code.is_redirection(),
            "not a redirection status code"
        );

        Self {
            status_code,
            location: HeaderValue::try_from(uri.to_string())
                .expect("URI isn't a valid header value"),
            _marker: PhantomData,
        }
    }
}

impl<R, ResBody> Service<R> for Redirect<ResBody>
where
    ResBody: Default,
{
    type Response = Response<ResBody>;
    type Error = Infallible;
    type Future = ResponseFuture<ResBody>;

    #[inline]
    fn poll_ready(&mut self, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
        Poll::Ready(Ok(()))
    }

    fn call(&mut self, _req: R) -> Self::Future {
        ResponseFuture {
            status_code: self.status_code,
            location: Some(self.location.clone()),
            _marker: PhantomData,
        }
    }
}

impl<ResBody> fmt::Debug for Redirect<ResBody> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("Redirect")
            .field("status_code", &self.status_code)
            .field("location", &self.location)
            .finish()
    }
}

impl<ResBody> Clone for Redirect<ResBody> {
    fn clone(&self) -> Self {
        Self {
            status_code: self.status_code,
            location: self.location.clone(),
            _marker: PhantomData,
        }
    }
}

/// Response future of [`Redirect`].
#[derive(Debug)]
pub struct ResponseFuture<ResBody> {
    location: Option<HeaderValue>,
    status_code: StatusCode,
    // Covariant over ResBody, no dropping of ResBody
    _marker: PhantomData<fn() -> ResBody>,
}

impl<ResBody> Future for ResponseFuture<ResBody>
where
    ResBody: Default,
{
    type Output = Result<Response<ResBody>, Infallible>;

    fn poll(mut self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Self::Output> {
        let mut res = Response::default();

        *res.status_mut() = self.status_code;

        res.headers_mut()
            .insert(header::LOCATION, self.location.take().unwrap());

        Poll::Ready(Ok(res))
    }
}